✅ Joint Pain

Question 1

Differential Diagnosis of Joint Pain

_{<strong>Antinuclear antibodies (ANA):</strong> nonspecific finding in SLE, Sjogren and scleroderma (95% sensitivity). Antinuclear antibodies characteristically occur in IgM form in patients with RA, but they are found less frequently than rheumatoid factors.}

_{Drug-induced lupus: <strong>Antihistone </strong>(95% specificity)}

_{SLE: Anti <strong>dsDNA</strong>/<strong>sm </strong>(96% specificity)}

_{Systemic sclerosis: <strong>Anti-Scl-70 </strong>(99% specificity)}

_{Limited systemic sclerosis: <strong>Anticentromere</strong> (97% specificity)}

_{Polymyositis/Dermatomyositis: <strong>Anti-Jo-1 </strong>(99% specificity)}

^{Rheumatoid Factor (70%Sensitivity); <strong>Anti CCP</strong> (95% specificity) in RA}

_{<strong>Anti-U1-ribonucleoprotein (RNP) antibodies </strong>are found in patients with mixed connective tissue disease, which is characterized by features of systemic sclerosis, polymyositis, and SLE.}

_{<strong>Anti-Ro/SSA and anti-La/SSB antibodies </strong>are present in 10% to 60% of patients with SLE; however, these antibodies are less specific than anti-dsDNA antibodies because they can also be present in patients with rheumatoid arthritis, systemic sclerosis, and Sjögren syndrome.}

Answer 1

Rheumatoid Arthritis

Ankylosing spondylitis

CPPD deposition disease

Gout

Infective endocarditis

Lyme disease

Osteoarthritis

Psoriatic arthritis

Peripheral arthritis associated with IBD

Reactive arthritis

Infectious arthritis

Systemic lupus erythematosus

Viral arthritis

Trochanteric bursitis

Anserine bursitis

Patellofemoral pain syndrome

Enteropathic Arthritis

Question 2

Ankylosing spondylitis

Answer 2

Inflammatory back pain

• Insidious onset at age <40
• Symptoms >3 months
• Relieved with exercise🏃🏼‍♂️ but not rest
• Nocturnal pain

Examination findings

• Arthritis (sacroiliitis)
• Reduced chest expansion & spinal mobility
• Enthesitis (tenderness at tendon insertion sites)
• Dactylitis (swelling of fingers & toes)
• Uveitis

Anterior uveitis (iritis) is the most common extraarticular manifestation of AS and occurs in 25%-40% of patients. It is characterized by inflammation of the uveal tract (iris, ciliary body, and choroid). Anterior uveitis typically presents with intense pain and photophobia in one eye.

Complications

• Osteoporosis/vertebral fractures
• Aortic regurgitation
• Cauda equina

Laboratory

• Elevated ESR & CRP
• HLA-B27 association

Imaging

• X-ray of sacroiliac joints
• MRI of sacroiliac joints

Inflammatory disorder of the axial skeleton; may have peripheral involvement; apical pulmonary fibrosis; back pain.

Hx: Onset of ankylosing spondylitis usually occurs in the teenage years or 20s and manifests as persistent pain and morning stiffness involving the low back that is alleviated with activity. This condition also may be associated with tenderness of the pelvis.

Differs from rheumatoid arthritis because ankylosing spondylitis uncommonly has peripheral involvement and usually involves the lumbar spine.

Dx:

MRI of the sacroiliac joints is most likely to establish the diagnosis.

CRX: Sacroiliitis; squaring of the vertebral bodies; bridging vertical enthesophytes

Cx: Patients with longstanding AS can develop osteopenia/osteoporosis due to increased osteoclast activity in the setting of chronic inflammation (mediated by TNF-α and interleukin-6). In addition, spinal rigidity in these patients can increase the risk of vertebral fracture, which often results from minimal trauma. Associated findings may include thoracic wedging and hyperkyphosis.

Question 3

Ganglion cysts

Answer 3

Swellings that overlie either joints or tendons most typically on the dorsal surface, develop as a result of chronic irritation of the wrist. If the cyst is not painful, no intervention is required.

Question 4

Gout (Crystal-induced synovitis)

Answer 4

Inflammatory response to monosodium urate crystals deposited into synovial tissue, bursae, and tendon sheaths due to chronic uric acid supersaturation of serum; urate deposits cause joint and tissue destruction over time.

Risk factors for gout

Increased risk

• Medications (eg, diuretics, low-dose aspirin)
• Surgery, trauma, recent hospitalization
• Volume depletion
• Diet: High-protein foods (meat, seafood), high-fat foods, fructose or sweetened beverages
• Heavy alcohol consumption
• Underlying medical conditions (eg, hypertension, obesity, chronic kidney disease, organ transplant)

Decreased risk

• Dairy product intake
• Vitamin C (≥1,500 mg/day)
• Coffee intake (≥6 cups/day)

Gout includes a group of clinical disorders ranging from acute, exquisitely painful, monoarticular arthritis to chronic, crippling, destructive polyarthritis. Progresses through three distinct stages: asymptomatic hyperuricemia, which may last several decades; acute intermittent gout; and chronic tophaceous gout, which usually develops only after years of acute intermittent gout.

A gout attack can be precipitated by conditions that cause increased production or decreased elimination of uric acid, or an acute change in uric acid levels. Common triggers include heavy alcohol consumption, intake of urate-rich foods, trauma/surgery, dehydration, and medications that raise (eg, thiazide diuretics, cyclosporine) or lower (eg, allopurinol) uric acid levels.

Hx: In the case of gout, frequently (75%) the first episode occurs in the great toe metatarsophalangeal joint (commonly referred to as podagra). Although it is most common in the first metatarsophalangeal joint, gout can also involve the knee and ankle. Gout is characterized by recurrent attacks that typically develop overnight or early in the morning, reaching maximum intensity within 12-24 hours. An active gouty joint is notable for warmth, swelling, and significant pain.

Estrogen promotes uric acid excretion, so 🚺 women typically DO NOT develop gout until the postmenopausal period.

Cx:

Tophi: Painless, persistent, generally noninflammatory nodules, which develop in tissues and tendons and are palpable on physical examination but also may occur as nodular lesions within joints or tissues

Tophi develop concomitantly with progressive gouty arthritis; although typically noninflammatory, an acute inflammatory response and local damage can occur at these sites

Dx: Arthrocentesis is performed in patients presenting with acute monoarticular arthritis to diagnose infection or crystal-induced arthritis. A definitive diagnosis of gout is made by demonstrating negatively birefringent monosodium urate crystals within synovial fluid leukocytes.

Tx: Advise patients with gout to avoid alcohol, because alcohol increases uric acid production and may impair uric acid excretion. Foods high in purines (eg, organ meats, red meat, seafood) also should be avoided.

Acute attacks:

Therapy with 🧯nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, or 🌿colchicine (if initiated within 36 hours of an attack). [🌑Corticosteroids can provide quick relief, but should be reserved if initial therapy fails.]

❗ NSAIDs should be avoided in patients who are older, who have chronic kidney disease, heart failure, peptic ulcer disease, or are on anticoagulation therapy.

Uric acid-lowering therapy:

Patients with recurrent episodes of gout who are at risk for joint damage are candidates for uric acid-lowering therapy. Management or prevention of recurrent gout and chronic tophaceous gout requires drug therapy to achieve and maintain serum uric acid levels below 6 mg/dL

🎲 Xanthine oxidase inhibitors (allopurinol or febuxostat). Allopurinol is typically safe and effective and is considered first-line therapy for most patients with an indication for uric acid lowering treatment. As uric acid-lowering therapy can precipitate an attack, it is recommended that prophylactic therapy with 🌿colchicine or low-dose 🧯NSAIDs be used in the first 3 to 6 months of uric acid-lowering therapy. Uricosuric agents (eg, probenecid, sulfinpyrazone) are occasionally effective in patients with low uric acid excretion (<600 mg daily) but are not effective in patients with a glomerular filtration rate <40 mL/min/1.73 m2.

Question 5

[Pseudogout] Calcium pyrophosphate dihydrate (CPPD) deposition disease

Answer 5

Deposition of CPPD crystals in and around joints, most commonly the wrist, MCP joints, shoulder, and knee.

May be asymptomatic or have a varied presentation resembling rheumatoid arthritis, osteoarthritis, or gout-like inflammation. Cartilage 🥛calcification termed chondrocalcinosis, especially in the knee, symphysis pubis, shoulder, hip, and triangular cartilage of wrist are pathognomonic.

Hx: No history of trauma; May be monoarticular or acute oligoarticular, with hot and red joints; may be chronic polyarticular in 5% of cases.

Osteoarthritis in unusual places (wrist, elbow, metacarpophalangeal joints, shoulder) without a history of trauma suggests CPPD deposition.

Px: Osteoarthritis in unusual places (wrist, elbow, metacarpophalangeal joints, shoulder)

Dx: The finding of chondrocalcinosis🥛 in a joint with a typical acute inflammatory arthritis establishes a diagnosis of probable CPPD crystal arthritis. Synovial fluid analysis will show an inflammatory effusion (15,000-30,000 cells/mm³) along with rhomboid-shaped, weakly positively birefringent CPPD crystals.

Cartilage calcification termed chondrocalcinosis, especially in the knee, symphysis pubis, shoulder, hip, and triangular cartilage of wrist, are pathognomonic.

2^O: Patients with pseudogout should be evaluated for secondary causes such as hyperparathyroidism, hypothyroidism, and hemochromatosis.

Question 6

Enteropathic Arthritis 💩

Answer 6

Arthritic conditions associated with gastrointestinal disease.

Up to 20% of patients with Crohn disease or ulcerative colitis develop inflammatory joint disease. Polyarthritis that resembles seronegative rheumatoid arthritis develops in 20% of these patients, whereas 10% to 15% of these patients develop spondylitis and sacroiliitis. The risk for inflammatory joint disease associated with Crohn disease or ulcerative colitis increases in patients with more advanced colonic conditions and additional concomitant extraintestinal manifestations, including abscesses, erythema nodosum, uveitis, and pyoderma gangrenosum. Peripheral arthritis associated with inflammatory bowel disease (IBD) is often classified as one of two types. In type I arthropathy, the peripheral arthritis tends to be acute, affects only a few joints, tends to occur early in the course of IBD, may worsen with flares of IBD, and is often self-limited. In type II arthropathy, more joints tend to be involved and symptoms may be migratory. Joint pain is usually not related to IBD activity, and symptoms may wax and wane over years. In patients with arthritis sensitive to flares of IBD, treating the underlying gastrointestinal disease is indicated. Additional treatment for sacroiliitis and peripheral joint disease is otherwise symptomatic.

Question 7

Osteonecrosis

Answer 7

Osteonecrosis (also known as aseptic, avascular, atraumatic or ischemic necrosis) occurs in disorders that disrupt the circulation of bone through micro-occlusion, abnormal endothelial function, or increased intraosseous pressure. It is a common complication of long-term glucocorticoid use, possibly due to effects on osteocytes or abnormal plasma lipid levels causing microemboli. Osteonecrosis causes bone and bone marrow infarction. Abnormal bone remodeling subsequently results in trabecular thinning and collapse over months to years. Osteonecrosis of the femoral head is characterized by pain in the groin, thigh, or buttock that is worsened by activity and relieved by rest. Progression of the disease can lead to reduced range of motion (usually abduction and internal rotation), rest pain, and joint instability. In the first few months, x-rays are often normal, and MRI is a more sensitive test. Osteonecrosis (“dry socket”) typically presents with gradual onset of pain in the weight-bearing joints (hip most common).

Question 8

Polymyositis

Answer 8

Peak incidence occurs at age 40-50, and women are more commonly affected than men. Proximal muscle weakness typically manifests as difficulty climbing stairs, getting into or out of a low chair 💺 or car, or working with the arms overhead (eg, combing hair) 💈. Involvement of upper esophageal musculature can cause dysphagia with regurgitation and aspiration. Inflammatory markers (eg, erythrocyte sedimentation rate) may be elevated, and most patients have detectable autoantibodies (eg, antinuclear antibody, anti-Jo-1).

Definitive diagnosis is established on muscle biopsy 🤜🏽. Polymyositis resembles dermatomyositis but without associated skin manifestations.

Initial remission can be induced with 🌑glucocorticoids (eg, prednisone), and most patients also receive a glucocorticoid-sparing agent (eg, methotrexate, azathioprine) to minimize the long-term adverse effects of treatment. Because polymyositis frequently occurs as a paraneoplastic syndrome, patients should also receive age-appropriate cancer screening.

Question 9

Polymyalgia rheumatica (PMR)

Answer 9

• Age >50
• Subacute-to-chronic (>1 month) pain in the shoulder, neck, and hip girdles
• Morning stiffness lasting >1 hour
• Constitutional symptoms
• Elevated erythrocyte sedimentation rate >40 mm/h
• No other apparent explanation for symptoms

Px: The physical examination is frequently unremarkable with patients having no focal tenderness or pain with active or passive range of motion. Signs of inflammation in the joints are absent. When asked to identify the location of their pain, patients typically indicate the soft tissues and not the joints.

Tx: Low-dose 🌚 glucocorticoids are the treatment of choice for PMR (eg, prednisone 10-20 mg daily). Rapid and thorough relief of symptoms is expected, and failure to improve rapidly on prednisone should call the diagnosis into question.

Cx: PMR is frequently associated with giant cell arteritis (GCA), also known as temporal arteritis. Symptoms of GCA include headache, jaw claudication, vision loss, or tenderness over the temporal artery. If GCA is suspected, patients should be considered for an expedited temporal artery biopsy and receive significantly higher doses of glucocorticoids (eg, prednisone 40-60 mg or higher daily).

Question 10

🔌 Myasthenia gravis

Answer 10

Epidemiology

• Women: 2nd to 3rd decade
• Men: 6th to 8th decade

Symptoms/signs

• Fluctuating & fatigable proximal muscle weakness that is worse later in the day
  
  • Ocular (eg, diplopia, ptosis)
  • Bulbar (eg, dysphagia, dysarthria)
  • Respiratory muscles (myasthenic crisis)

Causes of exacerbations

• Medications
  
  • Antibiotics: Fluoroquinolones, aminoglycosides
  • Anesthetics: Neuromuscular blocking agents
  • Cardiac medications: Beta blockers, procainamide
  • Other: Magnesium sulfate, penicillamine
  • Tapering of immunosuppressive medications
• Pregnancy/childbirth
• Surgery (especially thymectomy)
• Infection

Diagnosis

• Bedside: Edrophonium (Tensilon) test, ice pack test
• Acetylcholine receptor antibodies (highly specific)
• CT scan of chest to evaluate for thymoma

Treatment

• Acetylcholinesterase inhibitors (eg, pyridostigmine)
• ± Immunotherapy (eg, corticosteroids, azathioprine)
• Thymectomy

Myasthenia gravis is a NMJ disorder caused by autoantibodies against acetylcholine receptors in the motor end plate. Patients typically have fluctuating and fatigable extraocular (eg, diplopia, ptosis) and bulbar (eg, dysarthria, dysphagia) muscle weakness. They may also experience symmetric proximal weakness involving the neck (eg, difficulty holding up the head) and upper extremities (eg, difficulty 💈 combing hair). Sensation, reflexes, muscle bulk/tone, and autonomic function are usually intact.

Weakness can be exacerbated by various factors, including medications (eg, aminoglycosides, magnesium, beta blockers, neuromuscular blocking agents), surgery (particularly thymectomy), pregnancy, or infections.

Weakness that worsens with activity and involves facial and distal limb muscles in addition to proximal muscles.

IgG antibodies against AChR block neuromuscular transmission; thymus may be site of abnormal antibody production; caused by variable block of neuromuscular transmission related to an immune-mediated decrease in the number of functioning nicotinic acetylcholine receptors.

Px: Diplopia, ptosis; slurred speech; difficulty swallowing. The diagnosis of MG can be supported with the bedside ice pack test, in which an ice pack is applied over the eyelids for several minutes, leading to an improvement in ptosis.

Dx: The most commonly used pharmacologic test for patients with obvious ptosis or ophthalmoparesis is the edrophonium (Tensilon) test. Edrophonium is given intravenously in a dose of 10 mg (1 mL), of which 2 mg is given initially as a test dose and the remaining 8 mg approximately 30 seconds later if the test dose is well tolerated. In myasthenic patients, there is an obvious improvement in the strength of weak muscles that lasts for approximately 5 minutes.

Patients with established myasthenia gravis should receive chest imaging (eg, CT scan or MRI) to evaluate for thymoma as thymectomy can lead to long-term improvement.

Individuals with typical clinical features of myasthenia gravis should undergo confirmatory immunologic testing for acetycholine receptor antibodies (highly specific). Those with negative acetycholine receptor antibodies should subsequently be checked for muscle-specific tyrosine kinase antibodies. If the diagnosis remains unclear, electrophysiologic studies (eg, repetitive nerve stimulation, single-fiber electromyography) may be helpful. Impaired neuromuscular transmission can be detected electrophysiologically by a decremental response of muscle to repetitive supramaximal stimulation (at 2 or 3 Hz) of its motor nerve, but normal findings do not exclude the diagnosis.

Tx: Anticholinesterase Drugs

Myasthenic crisis is a life-threatening complication characterized by severe respiratory muscle weakness leading to respiratory failure (eg, accessory muscle use, hypoxemia, respiratory acidosis). Patients often have increasing generalized or bulbar weakness prior to the onset of crisis. The condition may be precipitated by infection (eg, urinary tract infection), surgery, pregnancy, or medications (eg, aminoglycosides, fluoroquinolones, macrolides, beta blockers). Patients with severe exacerbations and declining respiratory status should be monitored in the intensive care unit and intubated for airway protection.

Precipitating factors

• Infection or surgery
• Pregnancy or childbirth
• Tapering of immunosuppressive drugs
• Medications (eg, aminoglycosides, beta blockers)

Signs/symptoms

• ↑ Generalized & oropharyngeal weakness
• Respiratory insufficiency/dyspnea

Treatment

• Intubation for deteriorating respiratory status
• Plasmapheresis or IVIG as well as corticosteroids

Question 11

Osteoarthritis

Answer 11

Degeneration of articular cartilage, most often affecting the DIP, PIP, first CMC, first MTP, hip, and knee joints and the cervical and lumbar spine.

Hx: Common sites of osteoarthritis in the hand include the first carpometacarpal joint (base of the thumb), as well as the distal and proximal interphalangeal joints. Involvement of the carpometacarpal joint leads to “squaring” of the contour of the joint.

Pain occurs with use; minimal soft-tissue swelling and morning stiffness.

Characterized by joint-space narrowing with associated bony enlargement (osteophytes) with no acute signs of inflammation. Patients may have acute exacerbation of joint symptoms, especially after use.

According to the American College of Rheumatology’s clinical criteria, osteoarthritis of the knee can be diagnosed if knee pain is accompanied by at least three of the following features: age greater than 50 years, morning stiffness lasting less than 30 minutes, crepitus, bone tenderness, bone enlargement, and no palpable warmth.

Morning joint stiffness that persists for less than 30 minutes

Px: Passive range of motion of the knee often elicits pain at the extremes of flexion and extension.

Dx: Diagnosed (clinically) if knee pain is accompanied by at least three of the following features: age greater than 50 years, stiffness lasting less than 30 minutes, crepitus, bone tenderness, bone enlargement, and no palpable warmth.

CRX: Asymmetric joint-space narrowing; osteophytes; subchondral sclerosis and cystic changes; degenerative disk disease with collapse of disks; degenerative joint disease with facet joint osteophytes; these findings lead to spondylolisthesis (anterior/posterior misalignment of the spine) and kyphosis

Tx:

Weight loss for overweight or obese patients with lower extremity osteoarthritis coupled with both aerobic exercise as well as exercise to strengthen muscles proximate to the involved joint (ie, quadriceps muscle strengthening for knee osteoarthritis). More specifically, medial knee compartment osteoarthritis may benefit from heel inserts (5-10 degrees of lift), which help relieve the pressure on the medial compartment. Adaptive devices such as a cane in the hand contralateral to the painful joint may help by unloading forces on the knee or hip. Knee taping or bracing improves knee alignment, thus improving pain. Referral to physical or occupational therapy for active and passive range of motion exercise instruction or joint protection education may be helpful.

⬇

Rx: Acetaminophen is first-line pharmacologic therapy for osteoarthritis because it is safe, effective, and inexpensive. Patients with an inadequate response can be started on NSAIDs, preferably at the lowest effective dose to limit side effects (eg, gastrointestinal and renal toxicity, exacerbation of congestive heart failure and hypertension). Although cylcooxygenase-2-selective NSAIDs are somewhat less likely to cause gastrointestinal ulcers, they are not more effective than nonselective NSAIDs, are significantly more expensive, and are associated with an increased risk for adverse cardiovascular events.

Intra-articular glucocorticoids may be effective in providing pain relief and improving function. Successful injections provide pain relief for an average of 3 months. Intra-articular injection may be particularly useful in patients who obtain no relief from acetaminophen and have contraindications to the use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as chronic kidney disease, hypertension and a history of peptic ulcer disease.

Total joint arthroplasty should be considered for patients who do not adequately respond to nonsurgical methods. Replacement of the damaged joint restores normal biomechanics and often results in dramatic improvements in quality of life.

Question 12

Rheumatoid Arthritis

Answer 12

Rheumatoid arthritis is a symmetric polyarthritis that involves the small joints of the hands and feet as well as other joints throughout the body.

🚬Smoking is associated with an increased risk of developing rheumatoid arthritis. Hereditary factors convey susceptibility for developing rheumatoid arthritis, and changes in environmental factors seem to modify this risk. Users of smokeless tobacco do not have an increased risk of developing this disorder, suggesting that it is not simply an effect of nicotine.

Hx: Usually is a symmetric polyarthritis affecting large and small joints; it rarely presents as monoarthritis. Soft tissue (synovial) swelling rather than bony enlargement of the PIP and MCP joints. RA can affect most joints; however, the lumbar spine, thoracic spine. and distal interphalangeal joints are spared. Flares may be monoarticular and present as pseudoinfectious arthritis.

“Morning stiffness lasting more than 1 hour”

Inflammatory signs (fatigue, prolonged morning stiffness), rheumatoid nodules, and inflammatory synovial fluid.

Extra-articular: Vasculitis, dry eyes, dyspnea, or cough can all be seen. Cough and dyspnea may signal respiratory interstitial disease.

Although joint destruction in RA most commonly affects the small joints of the hands, the cervical spine can also be involved and may lead to subluxation (misalignment) of the atlantoaxial joints.

Dx: Rheumatoid factor is positive in 80% of cases. Synovial fluid analysis including Gram stain and culture usually will distinguish a flare from infectious arthritis.

CRX: Bony erosions; periarticular osteopenia; subluxations; soft-tissue swelling; MCP and PIP involvement on hand radiograph

Synovial fluid leukocyte count greater than 5000/µL (5 × 109/L).

Tx: Range-of-motion exercises help preserve joint motion; in patients with osteoarthritis, aerobic exercise helps maintain muscle strength, joint stability, and physical performance, and weight reduction reduces stress on weight-bearing joints.

DMARDs: Experts recommend that patients begin disease-modifying antirheumatic drugs (DMARDs) within 3 months of the onset of rheumatoid arthritis.

Methotrexate (Folic acid antimetabolite) 🍃

DMARD that is most likely to provide durable long-term response; often the initial choice

Takes 1-2 mo for full effect; frequently used in combination with other medications. Contraindicated in pregnancy and use with caution in patients who may become pregnant, have underlying liver or lung disease, immunosuppression, or infection. Folic acid supplementation prevents toxicity without interfering with efficacy.

Methotrexate is the preferred first-line DMARD for most patients with RA. Its effects are mediated by inhibition of dihydrofolate reductase, which causes cellular folate depletion leading to impaired DNA synthesis. Methotrexate can cause significant 🐄 hepatotoxicity, which can range from mild elevations in hepatic aminotransferases to chronic liver disease and cirrhosis. Serum liver studiesshould be checked prior to initiation of methotrexate and periodically during treatment. Patients should avoid alcohol intake. Much of the toxicity of methotrexate, including hepatotoxicity, can be mitigated by concurrent administration of folic (or folinic) acid 🐈, which does not reduce the effectiveness of the drug.

Hydroxychloroquine (Antimalarial agent with lysosomotropic action that affects immune regulation and inflammation)

Early, mild, and nonerosive disease; in combination with methotrexate or when methotrexate is contraindicated

Takes 2-6 mo for full effect; frequently used in combination regimens. Use with caution in patients who are pregnant or who have antimalarial allergy, G6PD deficiency, or retinal disease. Perform annual ophthalmologic examination.

Sulfasalazine (Unknown mechanism)

Early, mild, and nonerosive disease; in combination with methotrexate or when methotrexate is contraindicated

Takes 1-2 mo for full benefit. Use with caution in patients with sulfonamide or aspirin allergy, G6PD deficiency, kidney or liver disease, blood disease, or asthma.

Leflunomide (Pyrimidine synthesis inhibitor)

In combination with methotrexate or when methotrexate is contraindicated for progressive disease

Contraindicated in pregnancy; use with caution in patients who may become pregnant (known teratogen) or have liver disease.

Biologic Agents:

TNF inhibitors (adalimumab, etanercept, certolizumab pegol, golimumab, infliximab)(Immunomodulation)

When adequate disease control is not achieved with one or more oral DMARDs, biologic therapy is indicated. The preferred initial biologic agent is a tumor necrosis factor α (TNF-α) inhibitor such as etanercept, which is usually added to baseline methotrexate therapy. Use of a TNF-α inhibitor in addition to methotrexate is significantly more effective in controlling joint damage and improving function compared with single-agent therapy with either medication alone.

Testing for latent tuberculosis required before starting therapy.

Interleukin-1 receptor antagonist (anakinra) (Immunomodulation)

Uncontrolled disease despite use of DMARDs

Testing for latent tuberculosis required before starting therapy.

T-cell costimulatory blocker (abatacept)(Immunomodulation) (down-regulation of T cells)

Uncontrolled disease despite use of DMARDs

Testing for latent tuberculosis required before starting therapy.

B-cell depleting agent (rituximab)(Monoclonal antibody against CD20)

Uncontrolled disease despite use of DMARDs

Testing for latent tuberculosis required before starting therapy.

Anti-inflammatory Agents

NSAIDs (Inhibit cyclooxygenase)

Mild disease without erosions; as an adjunctive analgesic in more serious disease

NSAIDs do not prevent disease progression. Use with caution in patients with chronic kidney disease or ulcer disease.

Glucocorticoids (Suppress inflammation at multiple points along the inflammatory cascade)

Low-dose or intra-articular injections when NSAIDs do not control symptoms and when DMARDs have not yet produced an effect

High-dose glucocorticoids are useful in treating serious extra-articular manifestations (eg, vasculitis).

Cx: Rheumatoid arthritis is the most common cause of AA amyloidosis in the United States.

Question 13

Psoriatic arthritis

Answer 13

Hx: There are five patterns of joint involvement in psoriatic arthritis: involvement of the distal interphalangeal joints; asymmetric oligoarthritis; symmetric polyarthritis (similar to that of rheumatoid arthritis); arthritis mutilans (extensive osteolysis of the digits with striking deformity); and spondylitis (axial disease). Characteristic features of psoriatic arthritis include enthesitis (inflammation of sites where tendons or ligaments insert into bone), dactylitis (inflammation of an entire digit), and tenosynovitis (inflammation of the synovial sheath surrounding a tendon).

Common involvement of DIP joints, with fusiform swelling of digits and skin and nail changes consistent with psoriasis.

Synovial and entheseal swelling; may involve the DIP joints; dactylitis (sausage digits) present.

Characterized by joint distribution and appearance similar to that of reactive arthritis. Predilection for distal interphalangeal joints, often with concomitant nail pitting and onycholysis.

CRX: Destructive arthritis with erosions and osteophytes; DIP involvement; “pencil-in-cup” deformity on hand radiograph; arthritis mutilans

Question 14

Reactive arthritis

Answer 14

Reactive arthritis is a type of seronegative spondyloarthropathy. Reactive arthritis occurs in both men and women, and enthesitis and oligoarthritis are common.

Classic reactive arthritis consists of a triad of nongonococcal urethritis, asymmetric oligoarthritis and conjunctivitis. The arthritis often involves the knee and sacroiliac spine.

Hx: The classic triad of arthritis, urethritis, and conjunctivitis occurs in only about one third of patients.

Manifests within 2 months of an episode of bacterial gastroenteritis or n_ongonococcal urethritis_ or cervicitis in a genetically predisposed patient.

Reactive arthritis was previously called Reiter syndrome, which referred to the coincidence of arthritis, conjunctivitis, and urethritis (or cervicitis). However, only about one third of patients have all three symptoms.

Reactive arthritis usually affects the peripheral joints, often in the lower extremities, although inflammatory back pain also may be present.

Patients may also present with heel pain with enthesitis; keratoderma blennorrhagicum on the palms or soles; or circinate balanitis on the penis.

Differs from rheumatoid arthritis in that it is oligoarticular and asymmetric?

Presents as symmetric? inflammatory oligoarthritis, most often involving weight-bearing joints; may include tendon insertion inflammation (enthesitis).

Extra-articular manifestations include conjunctivitis, urethritis, stomatitis, and psoriaform skin changes (hyperkeratotic lesions on the palms and soles). Infection with Salmonella, Shigella, Yersinia, Campylobacter, or Chlamydia species within 3 wk prior to onset of initial attack.

Synovial fluid analysis is usually sterile. 🧯 Nonsteroidal anti-inflammatory agents (NSAIDs) are the first line therapy during the acute phase of this condition.

Question 15

Disseminated gonococcal infection

Answer 15

Disseminated gonococcal infection

• Purulent monoarthritis OR Triad of tenosynovitis, dermatitis, migratory polyarthralgia

Diagnosis

• Detection of Neisseria gonorrhoeaein urine, cervical, or urethral sample
• Culture of blood, synovial fluid (less sensitive)

Treatment

• 3rd-generation cephalosporin IV AND oral azithromyci

Migratory joint symptoms and often have involvement of several joints with tenosynovitis.

Skin lesions are found in more than 75% of patients with DGI but may be few in number; consequently. Lesions are most likely to be found on the extremities. The classic lesion is characterized by a small number of necrotic vesicopustules on an erythematous base.

Dx: Nucleic acid amplification urine test (NAAT) for Neisseria gonorrhoeae is a noninvasive, sensitive test for diagnosing gonorrhea in men. This test provides rapid results (within hours) and can help to guide therapy pending return of blood and synovial fluid culture results.

Mucosal cultures, including of the throat, anus, urethra, or cervix (in women), may also be helpful in establishing the diagnosis.

Tx: Infection of cervix, urethra, or rectum:

Ceftriaxone 125 mg IM, given in a single dose, PLUS either azithromycin 1 g orally in a single dose or doxycycline 100 mg orally twice daily for 7 days

Question 16

RA cervical myelopathy

Answer 16

Symptoms

• Neck pain radiating to occipital region
• Slowly progressive spastic quadriparesis
• Painless sensory deficits in hands or feet
• Respiratory dysfunction (eg, from vertebral artery compression)

Signs

• Protruding anterior arch of atlas
• Scoliosis with loss of cervical lordosis
• Upper motor neuron signs (eg, spastic paresis, hyperreflexia, Babinski sign)
• Hoffman sign

Although joint destruction in RA most commonly affects the small joints of the hands, the cervical spine can also be involved and may lead to subluxation (misalignment) of the atlantoaxial joints. Patients with severe RA (eg, elevated inflammatory markers, rapidly progressive erosive disease) and peripheral joint subluxation (eg, hand deformities) are at increased risk. Forced neck extension during intubation can worsen the subluxation, leading to cord compression and progressive cervical myelopathy; complete dislocation can result in paralysis and death.

The earliest symptom of atlantoaxial subluxation is typically cervical pain that radiates to the occiput. Cervical myelopathy classically presents with slowly progressive, spastic paraparesis characterized by weakness involving the upper and lower extremities, hyperreflexia, and sensory changes. Upper motor neuron signs, including Babinski sign, are present. Hoffman sign (flexion and adduction of the thumb when flicking the nail of the middle finger) suggests a corticospinal tract lesion and supports the diagnosis of cervical myelopathy; however, it is nonspecific and may be seen in normal patients.

Patients with evidence of subluxation should undergo urgent MRI of the cervical spine which demonstrates separation of C1 and C2. Management involves stiff surgical collars and neurosurgical intervention (eg, cervical fixation).

Question 17

Tendonitis

Answer 17

An acute (sudden, short-term) condition in which inflammation is caused by a direct injury to a tendon.

Rotator cuff tendinopathy (RCT) results from repetitive activity above shoulder height (eg, painting ceilings) and is common in middle-aged and older individuals. Chronic tensile loading and compression by surrounding structures can cause microtears, fibrosis, and inflammatory calcification in the rotator cuff tendons (especially supraspinatus). Pain may also emanate from the subacromial bursa and the tendon of the long head of the biceps. On flexion or abduction of the humerus, the space between the humeral head and acromion is reduced, causing pressure on the supraspinatus tendon and subacromial bursa. Impingement syndrome, a characteristic of RCT, refers to compression of these soft tissue structures. Impingement can be demonstrated with the Neer test: With the patient’s shoulder internally rotated and forearm pronated, the examiner stabilizes the scapula and flexes the humerus. Reproduction of the pain is considered a positive test.

Question 18

Tendinosis

Answer 18

A chronic (persistent or recurring) condition caused by repetitive trauma or an injury that hasn’t healed.

Question 19

SHOULDER/ELBOW/WRIST/HAND

Question 20

👍🏽 de Quervain tenosynovitis

Answer 20

Caused by inflammation of the abductor pollicis longus and extensor pollicis brevis tendons in the thumb.

It is usually associated with repetitive use of the thumb but can also be associated with other conditions, including pregnancy, rheumatoid arthritis, and calcium apatite deposition disease. The typical presentation is of pain on the radial aspect of the wrist that occurs when the thumb is used to pinch or grasp. Examination findings include localized tenderness over the distal portion of the radial styloid process and pain with resisted thumb abduction and extension.

de Quervain tendinopathy (DQT) is an overuse syndrome involving the tendons of the abductor pollicis longus and extensor pollicis brevis and occurs most prominently at the point where the tendons pass under the extensor retinaculum in the first dorsal compartment. It most commonly occurs in women age 30-50 and is seen in higher frequencies 4-6 weeks postpartum, possibly because of repetitive thumb abduction and extension when lifting the infant.

The diagnosis of DQT is based on clinical features. Examination typically shows tenderness at the radial side of the wrist at the base of the hand. In addition, the Finkelstein test (adduction of the wrist with the fingers closed over the thumb in a fist) causes passive stretching of the tendons over the radial styloid; reproduction of the pain in this maneuver is strongly suggestive of DQT. Conservative management with nonsteroidal anti-inflammatory drugs (eg, ibuprofen) and thumb spica splinting is usually adequate.

Question 21

Brachial Plexus Injury

Answer 21

C5 - C6 nerve root compression

Hx: Pain radiates down arm

Px: Neuro Examination

Question 22

Adhesive capsulitis (“frozen shoulder”)

Answer 22

Characterized by fibrosis and contracture of the glenohumeral joint capsule. The stiff glenohumeral joint is most likely a result of chronic inflammation and fibrosis.

Hx: “Female, fat, fertile and forty” + thyroid, and parkinson’s.

Causes a painful and stiff shoulder usually without a known inciting event. Gradual onset of shoulder stiffness, with or without mild pain, that limits their ability to flex, abduct (eg, reach overhead), or rotate the humerus.

AC can be idiopathic or secondary to underlying conditions such as rotator cuff tendinopathy (most common), subacromial bursitis, paralytic stroke, diabetes mellitus, or humeral head fracture.

Dx: Diagnosis is confirmed on examination with >50% reduction in both passive and active ROM.

Question 23

Lateral epicondylitis

Answer 23

Lateral epicondylitis is due to overuse of the extensor muscles, primarily the extensor carpi radialis brevis and the extensor digitorum communis. The primary pathologic lesion is noninflammatory angiofibroblastic tendinosis at the common extensor origin on the lateral epicondyle of the humerus. An analogous disorder can occur at the origin of the wrist flexors at the medial epicondyle (medial epicondylitis). Patients usually have a history of repetitive, forceful extension at the wrist. Examination findings may include tenderness at the lateral epicondyle and reproduction of pain with resisted extension or passive flexion at the wrist.

Management includes activity modification, nonsteroidal anti-inflammatory drugs, and counterforce bracing.

Question 24

Olecranon bursitis

Answer 24

Olecranon bursitis is due to repetitive pressure or friction on the elbows. It presents with posterior elbow pain and is usually associated with visible swelling of the bursal sac.

Question 25

Monte gg ia:

Answer 25

proximal ulna; radial head

Question 26

Radial tunnel syndrome

Answer 26

Radial tunnel syndrome causes posterolateral elbow pain similar to that in lateral epicondylitis and may occur in conjunction with that condition. Findings include weakness of extension at the wrist and third digit, reproduction of pain on resisted supination of the forearm, and pain at the radial tunnel on resisted hyperextension of the wrist.

Question 27

FOOSH

Answer 27

Scaphoid

Distal forearm

Distal radius

Question 28

Scaphoid fractures

Answer 28

Scaphoid fractures are the most common of the carpal bone fractures. They frequently result from falls onto an outstretched hand (“FOOSH” injury) that cause direct axial compression or wrist hyperextension. A scaphoid fracture should be suspected in any patient with persistent wrist pain and tenderness in the anatomical snuffbox.

The snuffbox is a shallow depression at the dorsoradial wrist bounded medially by the tendon of the extensor pollicis longus and laterally by the tendons of the abductor pollicis longus and extensor pollicis brevis. The scaphoid and trapezium bones form the floor of the snuffbox.

Dx: X-ray at the time of injury has low sensitivity for scaphoid fracture. Therefore, if initial x-rays are negative, CT scan or MRI of the wrist is recommended to confirm the fracture. As an alternative, the wrist can be immobilized briefly in a thumb spica splint, followed by repeat imaging in 7-10 days. Either approach can be considered; repeat x-ray is associated with lower up-front costs, whereas MRI may allow for earlier return to normal activity.

Cx: Failure to restore or protect potentially compromised circulation to the scaphoid may result in avascular necrosis of the proximal portion of the bone. Delayed or non-union of scaphoid fractures is also a concern, and can lead to post-traumatic arthritis.

Question 29

Distal Radius (Colles) Fracture

Answer 29

Commonly occurs after falling on an outstretched hand, particularly in athletes (high-impact falls) or elderly patients with osteoporosis (low-impact falls).

A dorsally displaced, dorsally angulated fracture of the distal radius and the ulnar styloid that typically can be reduced well with closed manipulation. Characteristic manifestations include pain, swelling, and 🍴dinner fork deformity of the wrist. In addition, severely displaced fractures may result in neurovascular compromise; therefore, careful assessment of pulse, capillary refill, and sensation is indicated.

Dorsal displacement of the radius can result in compression of the median nerve, which enters the wrist through the carpal tunnel and provides sensation to the lateral 3½ digits and motor innervation to the thenar muscles (eg, opponens pollicis, abductor pollicis brevis).

Compression results in acute carpal tunnel syndrome symptoms, including paresthesia of the affected digits and impaired thumb abductionby abductor pollicis brevis. Furthermore, if compression occurs proximal to the tunnel, the palmar cutaneous branch of the median nerve may be affected, leading to decreased sensation over the anterolateral hand.

Tx: A short arm cast will immobilize the wrist and allow elbow mobility which will provide great functional quality of life.

Question 30

Distal forearm fractures

Answer 30

Distal forearm fractures are common in children and typically occur after a fall onto an outstretched hand. Because the periosteum surrounding the bone is thick and strong in children, the fracture may involve only one side of the bony cortex rather than extending through the width of the bone. This is known as a greenstick fracture.

Tx: Prompt reduction (if displaced) and immobilization of the forearm is required for greenstick fractures because they are considered unstable due to the potential for refracture or further displacement if improperly treated.

Repeat x-rays should be performed prior to cast removal to confirm bony union. Once the fracture is fully healed, no long-term complications are expected.

Question 31

Keinbock disease

Answer 31

AVN of lunate

Question 32

Trigger Finger

Answer 32

In trigger finger (TF), one of the most common causes of hand pain and disability, the flexor tendon causes painful popping or snapping as the patient flexes and extends the digit. The patient may present with a digit locked in a particular position, most often flexion, which may require gentle, passive manipulation into full extension. Systemic causes of TF are collagen-vascular diseases, including the following [21] : RA, DM , Psoriatic arthritis, Amyloidosis, Hypothyroidism, Sarcoidosis, Pigmented villonodular synovitis.

Question 33

Carpal Tunnel

Answer 33

Risk factors

• Obesity
• Pregnancy
• Diabetes
• Hypothyroidism
• Rheumatoid arthritis
• End-stage renal disease/hemodialysis

Clinical presentation

• Pain & paresthesia in median nerve distribution (first 3½ digits)
• Positive Phalen test & Tinel sign
• Severe disease: weakness of thumb abduction & opposition, atrophy of thenar eminence

Confirmatory test

• Nerve conduction studies

Treatment

• Wrist splinting

Most patients with mild CTS will respond to conservative measures, including nocturnal wrist splinting, which holds the wrist in a neutral position and prevents excessive flexion during sleep.

• Glucocorticoid injection
• Surgery for severe or refractory symptoms

The carpal tunnel is an anatomic space in the wrist defined by the carpal bones on the dorsal aspect and the transverse carpal ligament (flexor retinaculum) on the volar aspect. The ligament attaches to the hamate and pisiform on the ulnar side and to the trapezium and scaphoid tuberosity on the radial side. The carpal tunnel contains the flexor digitorum profundus tendons, the flexor digitorum superficialis tendons, the flexor pollicis longus tendon, and the median nerve.

Compression of the median nerve within the tunnel produces carpal tunnel syndrome, which is characterized by pain and paresthesias in the median nerve territory. #1 CARDINAL SYMPTOM IS NOCTURNAL PAIN!!!! Motor involvement causes weakness of thumb abduction and opposition.

Pathophysiologic features:

Idiopathic/overuse

• Swelling & fibrosis of tendons & soft tissue

🎀 Hypothyroidism

• Soft tissue enlargement (mucopolysaccharides)

In addition to slowed metabolic activity, many symptoms of hypothyroidism (eg, myxedema, dry skin) are due to deposition of mucinous material composed of glycosaminoglycans, hyaluronans, and mucopolysaccharides within tissue. Direct infiltration of the median nerve and nerve sheath with mucinous material results in swelling and a localized ischemic neuropathy. Deposition on the tendons within the carpal tunnel results in swelling and compression on the nerve, leading to symptoms of CTS. Patients with hypothyroidism are more likely to develop bilateral CTS, and their symptoms may be more severe. The risk does not appear to correlate with the severity of the underlying thyroid disease, although it is greater in patients with elevated BMI. Treatment of hypothyroidism with levothyroxine often leads to improvement of CTS symptoms.

Diabetes mellitus

• Soft tissue enlargement
• Microvascular insufficiency & neovascularization

Rheumatoid arthritis

• Extrinsic compression from joint deformity

Pregnancy

• Edema/fluid accumulation

End-stage renal disease

• Amyloid & calcium phosphate deposition
• Access related (bleeding, venous hypertension during HD, vascular steal)

Acromegaly

• Tendon enlargement
• Synovial edema

Gout

• Compression from tophi

Question 34

Dupuytren’s contracture

Answer 34

Dupuytren disease is a fibrosing disorder that results in slowly progressive thickening and shorting of the palmar fascia and leads to debilitating digital contractures, particularly of the metacarpophalangeal (MCP) joints or the proximal interphalangeal (PIP) joints. This condition usually affects the fourth and fifth digits (the ring and small fingers). See the images below. TF results from thickening of the flexor tendon within the distal aspect of the palm. [2, 3] This thickening causes abnormal gliding and locking of the tendon within the tendon sheath. Specifically, the affected tendon is caught at the edge of the first annular (A1) pulley.

Question 35

De Quervian tenosynovitis

Answer 35

De Quervian tenosynovitis is a condition that classically affects new mothers who hold their infants with the thumb outstretched (abducted / extended). This condition is caused by inflammation of the abductor pollicis longus (APL) and extensor pollicis brevis (APB) tendons as they pass through a fibrous sheath at the radial styloid process. Tenderness can typically be elicited with direct palpation of the radial side of the wrist at the base of the hand. Additionally, the Finkelstein test, which is conducted by passively stretching the affected tendons by grasping the flexed thumb into the palm with the fingers, elicits pain.

Question 36

Fracture complicated by nonunion

Answer 36

Defined as failure of a fracture to achieve radiographic or clinical evidence of union within an adequate time frame (eg, 6 months for long bone shaft fractures). Risk factors for nonunion include impaired blood flow (eg, smoking, arterial atherosclerosis), certain medications (eg, systemic glucocorticoids), metabolic disorders (eg, diabetes, hypothyroidism), and infection (eg, osteomyelitis).

Question 37

HIP/KNEE/FOOT

Question 38

Avascular necrosis

Answer 38

Use of glucocorticoids and excessive alcohol intake are associated with more than 80 percent of atraumatic cases.

Question 39

Acetabular labrum injury

Answer 39

The intra-articular cause of “snapping hip”.

Plain radiographs of the pelvis are the initial studies obtained when a labral tear is suspected.

The most accurate imaging study for diagnosing labral tears is a magnetic resonance arthrogram (MRA)

Tx: Initial management of labral tears consists of activity modification (ie, rest from inciting activities) and physical therapy. Strengthening of the pelvic and lower extremity muscles helps to stabilize the joint and correct abnormal pelvic tilt, relieving some of the abnormal stress placed on the labrum.

If physical therapy fails, arthroscopic surgery is indicated.

Question 40

DJD

Answer 40

Overweight

Question 41

Trochanteric bursitis

Answer 41

inflammation of the bursa surrounding the insertion of the gluteus medius onto the femur’s greater trochanter. Excessive frictional forces secondary to overuse, trauma, joint crystals, or infection are responsible. Patients with this condition complain of hip pain when pressure is applied (as when sleeping) and with external rotation or resisted abduction.

Hx: Caused by friction of the tendons of the gluteus medius and tensor fascia lata over the greater trochanter. Pain is localized to the lateral hip and is worsened by direct pressure.

Patients describe pain when lying on their side or swinging their leg into a car.

Px: Hip range of motion is normal; although patients may indicate that they believe they are having pain in the joint, nonarticular pain is often worse with active range of motion and is localized away from the joint on palpation.

Question 42

OVERUSE INJURIES OF THE KNEE 🦵

Answer 42

Patellofemoral syndrome

• Women much more than men
• Poorly localized anterior pain
• Pain reproduced with patellofemoral compression during extension

Iliotibial band syndrome

• Poorly localized lateral pain
• Tenderness at lateral femoral epicondyle with flexion & extension

Pes anserine bursitis

• Highly localized medial pain
• Point tenderness at the pes anserine bursa

Patellar tendinitis

• Common in jumping sports (eg, basketball, volleyball)
• Moderately localized pain at & below patella
• Tenderness at inferior margin of patella

Prepatellar bursitis

• Common in patients who work on their knees (“housemaid’s knee”)
• Bogginess & tenderness at inferoanterior aspect of knee
• Propensity to secondary infection with Staphylococcus aureus

Question 43

Iliotibial band syndrome (Knee)

Answer 43

The most common cause of lateral knee pain in young athletes such as runners or cyclists.

Hx: Knife-like lateral knee pain that occurs with vigorous flexion-extension activities of the knee. Patients often describe pain that radiates down the outside of the leg.

Px: Pain to palpation along the band down to the knee. Stretching of the iliotibial band by adducting the knee often reproduces the pain.

Tx: Treated conservatively with rest and stretching exercises; strengthening the hip abductors, internal rotators, and knee flexors

Question 44

Meniscal injury

Answer 44

Meniscal tears in young patients are typically caused by an acute rotational force on a planted foot. There is often an associated effusion and a sensation of instability. Examination findings include medial joint line tenderness and palpable locking or catching when the joint is rotated or extended while under load (eg, Thessaly test, McMurray test).

Hx: Locking, catching, or giving way

Question 45

Pes Anserine bursitis

Answer 45

Pes anserinus pain syndrome can be caused by an abnormal gait, overuse (running), or trauma. Risk factors include obesity, diabetes mellitus, knee osteoarthritis, and angular deformity of the knee.

Patients experience localized pain over the anteromedial tibia, which is often exacerbated by pressure from the opposite knee while lying on the side.

Examination shows a well-defined area of tenderness over the medial tibial condyle just below the joint line; swelling, erythema, and induration are typically absent. The diagnosis is based primarily on clinical features, although x-ray can exclude concurrent osteoarthritis of the knee.

Tx: Management includes quadriceps strengthening exercises and nonsteroidal anti-inflammatory drugs.

Question 46

Patellofemoral pain syndrome

Answer 46

The most common cause of knee pain in patients younger than age 45 years. The pain is peripatellar and exacerbated by overuse (such as running), descending stairs, or prolonged sitting (theatre sign).

Hx: Anterior knee pain that is made worse with prolonged sitting and with going up and down stairs.

Px: The pain is reproduced by applying pressure to the patella with the knee in extension and moving the patella both medially and laterally (patellofemoral compression test).

Tx: Treatment is done primarily through strengthening the quadriceps muscles and hip rotators.

Question 47

Prepatellar bursitis “housemaid’s knee”

Answer 47

Hx: Pain and swelling directly over the patella, usually following trauma or extended periods of kneeling. Common in occupations requiring repetitive kneeling, such as concrete work, carpet laying, and plumbing.

While bursitis in other locations is generally noninfectious, acute prepatellar bursitis is very commonly due to Staphylococcus aureus, which can infect the bursa via penetrating trauma, repetitive friction, or extension from local cellulitis.

Dx: The diagnosis should be confirmed with aspiration of bursal fluid for cell count and Gram stain.

Tx: If Gram stain and culture are negative, patients may be managed with activity modification and nonsteroidal anti-inflammatory drugs. Otherwise, patients are treated with drainage and systemic antibiotics.

Question 48

Patellar dislocation

Answer 48

Risk factors

• Joint laxity
• Misaligned lower extremity
• Tight iliotibial band
• Patellar subluxation
• Competitive sports, dance, military training

Clinical presentation

• Quick, twisting motion around a flexed knee
• Feeling of knee giving way, severe pain, popping noise
• Examination: lateral dislocation of patella, decreased extension

Usually occurs after quick, lateral movements on a flexed knee and is most common in young athletes (eg, soccer or ice hockey players, gymnasts), dancers, and military trainees.

Patients may feel the knee giving way, followed by a “popping noise” and severe pain. The quadriceps muscles normally exert a lateral force on the patella, especially during quadriceps contraction; therefore, in cases of patellar dislocation, lateral displacement with associated tear of the medial patellofemoral ligament (which normally provides an opposing medial force) is most common. Superior and medial dislocations are rare. Risk factors for patellar dislocation include age <20, joint laxity, lower extremity malalignment, and patellar subluxation (excess lateral movement within the trochlea).

Examination shows a flexed knee with reduced range of motion and lateral displacement of the patella (seen as a large, immobile deformity) out of the trochlea, which may be palpable as a depression at the anterior knee. Other findings can include hemarthrosis and tenderness along the medial patella (reflecting tear of the medial patellofemoral ligament). X-rays may not be needed for diagnosis in clinically apparent dislocation but are performed after reduction to rule out additional injuries.

Patellar dislocation often reduces spontaneously. However, closed reduction is required for patients without spontaneous resolution. Follow-up care includes splinting and rehabilitation for muscle strengthening.

Question 49

Quadriceps tendon tear

Answer 49

Sudden, forceful contraction, as can occur in deceleration from a fall or in certain athletic activities, can cause rupture of the quadriceps–patellar tendon complex. Tendon injuries can be categorized in relation to the patella:

Quadriceps tendon tears (proximal to the patella in the rectus femoris tendon): the patella rides low, indicating an intact connection to the tibia, with a palpable defect above the patella

Patellar tendon tears (distal to the patella): the patella rides high, often with a palpable defect below the patella (the nomenclature can be confusing as the patellar tendon is actually a ligament)

Typical symptoms include an “audible popping”, rapid swelling, and inability to actively extend the knee against gravity. Risk factors include chronic kidney disease, hyperparathyroidism, and anabolic steroid abuse. Exposure to fluoroquinolone antibiotics may also increase the risk. The diagnosis and extent of the injury can be assessed on MRI. Management of complete tears of the quadriceps tendon requires surgical intervention.

Question 50

Popliteal (baker) cyst

Answer 50

Due to extrusion of synovial fluid from the knee joint into the gastrocnemius or semimembranosus bursa through a communication between the joint and the bursa. Excessive synovial fluid formation (eg, due to osteoarthritis or rheumatoid arthritis) and positive pressure in the knee during extension can cause passage of fluid into the bursa and gradual enlargement of the cyst.

Often asymptomatic and present as a chronic, painless bulge behind the knee. The diagnosis is usually apparent on examination, with a soft mass in the medial popliteal space that is most noticeable with knee extension and less prominent with flexion.

Cx: Rupture of a popliteal cyst (eg, following strenuous exercise) can cause posterior knee and calf pain, with tenderness and swelling of the calf resembling deep venous thrombosis (DVT). An arcarc of ecchymosis is often visible distal to the medial malleolus (“crescent sign”). Ultrasound can rule out DVT and confirm the popliteal cyst.

Question 51

🦶Ottawa ankle rules

Answer 51

Ottawa ankle rules are a useful guide to use to determine if radiographs are indicated after an ankle sprain.

Films should be obtained if:

• The patient is unable to walk four steps immediately after the injury and in the office.
• There is tenderness over the distal 6 cm of the tibia or fibula, including the malleoli.
• There is midfoot or navicular tenderness.
• There is tenderness over the proximal fifth metatarsal.

Question 52

Maiso”nneuve”:

Answer 52

Ankle with medial malleolus; fibular head

Question 53

Charcot joint

Answer 53

Pathogenesis involves decreased proprioception, pain, and temperature perception, which can occur due to diabetes, peripheral nerve damage, syringomyelia, spinal cord injury, vitamin B12 deficiency, or tabes dorsalis. As normal neurologic input is lost, patients unknowingly traumatize their weight-bearing joints. This causes secondary degenerative joint disease, joint deformation, and functional limitation. X-rays will reveal loss of cartilage, osteophyte development, and loose bodies. In diabetes, vasculopathy also contributes to disease pathogenesis. Associated pain is typically mild. Management of a Charcot joint involves treating the underlying disease and providing mechanical devices (eg, special shoes) to assist in weight bearing and decrease further trauma.

Question 54

Stress fracture

Answer 54

Risk factors

• Repetitive activities (eg, running, gymnastics)
• Abrupt increase in physical activity
• Inadequate calcium & vitamin D intake
• Decreased caloric intake
• Female athlete triad: low caloric intake, hypomenorrhea/amenorrhea, low bone density

Clinical presentation

• Insidious onset of localized pain
• Point tenderness at fracture site
• Possible negative x-ray in the first 6 weeks

Management

• Reduced weight bearing for 4-6 weeks
• Referral to orthopedic surgeon for fracture at high risk for malunion (eg, anterior tibial cortex, 5th metatarsal)

Stress fractures are caused by repeated tension or compression without adequate rest and most commonly occur in athletes and military recruits who suddenly increase their activity. The second metatarsal, which is subjected to significant extremes of loading during gait, is the most commonly involved metatarsal. Typical findings include subacute, activity-related pain and point tenderness over the fracture. The diagnosis is primarily based on clinical findings. X-rays may initially be normal but can show a hairline lucency or local periosteal thickening. MRI, CT, and scintigraphic bone scans are more sensitive, especially for early fracture, but are not usually needed.

Fractures of the second, third, and fourth metatarsals are managed conservatively as the surrounding metatarsals act as splints and nonunion is uncommon. Initial interventions include rest and simple analgesics (eg, acetaminophen). Some experts advise against nonsteroidal anti-inflammatory drugs due to a possible delay in healing times. Patients who continue to have pain despite activity restrictions may additionally be managed with a wide, hard-sole podiatric shoe.

Stress fracture of the femoral neck

A stress fracture of the femoral neck may manifest as lateral hip pain. This condition should be suspected in runners whose pain consistently occurs before the end of a run.

Question 55

Plantar fasciitis

Answer 55

Risk factors

• Pes planus
• Obesity
• Working or exercising on hard surfaces

Symptoms

• Pain at plantar aspect of heel & hindfoot
• Worse with weight bearing (especially after prolonged rest)

Diagnosis

• Tenderness at insertion of plantar fascia
• Pain with dorsiflexion of toes
• Presence of heel spurs on x-ray has low sensitivity & specificity

Treatment

• Activity modification
• Stretching exercises
• Heel pads/orthotics

Plantar fasciitis is most common in obese, middle-aged adults, but it may also be seen in younger, well-conditioned individuals who participate in high-impact exercise or spend extended periods in bare feet. Plantar fasciitis is characterized by inflammation and degeneration of the plantar aponeurosis (deep plantar fascia), a thick, fibrous band that extends from the calcaneus to the toes and supports the longitudinal arch of the foot. It is thought to be due to chronic overuse and repetitive microtrauma to the aponeurosis and its insertion point at the calcaneus.

The diagnosis of plantar fasciitis is based on clinical factors. The pain is often worst when first standing from rest; it may lessen with activity but may again worsen after long periods of standing or walking.

Physical examination typically shows tenderness at the insertion of the plantar fascia at the calcaneus, especially with the toes passively dorsiflexed. Patients frequently have preexisting abnormalities of the arch (eg, pes planus, high arch).

X-ray may show calcifications in the proximal plantar fascia (“heel spurs”), but this finding is neither sensitive nor specific, and imaging is done primarily to rule out other causes of pain. Initial management includes activity modification (eg, avoiding walking barefoot, reducing high-impact exercise), stretching exercises, and padded heel inserts. However, the plantar aponeurosis recovers slowly; the long-term outcome is generally good, but symptoms may require months or even years for complete resolution.

Question 56

Interdigital (Morton) Neuroma

Answer 56

Interdigital (Morton) Neuroma The disorder is not a true neuroma but is a mechanically induced neuropathic degeneration of the interdigital nerves that causes numbness, aching, and burning in the distal forefoot from the metatarsal heads to the third and fourth toes. The symptoms are worsened by walking on hard surfaces and wearing tight or high-heeled shoes. The diagnosis of Morton neuroma is primarily made clinically. On examination, squeezing the metatarsal joints will cause pain on the plantar surface of the foot along with crepitus “clicking” between the third and fourth toes (Mulder sign). Treatment involves metatarsal support with a bar or padded shoe inserts to decrease pressure on the metatarsal heads. Surgery is usually reserved for patients who fail conservative treatment.

Question 57

Tarsal tunnel syndrome

Answer 57

Caused by entrapment and compression of the tibial nerve where it passes under the flexor retinaculum at the medial aspect of the ankle. It presents with numbness and paresthesias at the toes and distal sole.

Question 58

🥼 Differential diagnosis of neck pain

Answer 58

Strain

• Antecedent history of neck injury
• Pain/stiffness with neck movement

Facet osteoarthritis

• Older individuals
• Pain/stiffness worse with movement
• Relieved with rest

Radiculopathy

• Pain radiates to shoulder/arm
• Dermatomal sensory/motor/reflex findings
• Positive Spurling test

Spondylitic myelopathy

• LE weakness, gait/bowel/bladder dysfunction
• Lhermitte sign

Spondyloarthropathy

• Young men
• HLA-B27
• Relieved with exercise
• Prolonged morning stiffness

Spinal metastasis

• Constant pain
• Worse at night
• Not responsive to position changes

Vertebral osteomyelitis

• Focal tenderness
• Fevers & night sweats
• IVDU, immune compromise, or recent infection

Question 59

Cervical spondylosis

Answer 59

Cervical spondylosis affects 10% of people older than 50 years of age. The history of chronic neck pain is typical. Typical radiographic findings include bony spurs and sclerotic facet joints.

Cervical spondylosis results from chronic cervical disk degeneration, with herniation of disk material, secondary calcification, and associated osteophytic outgrowths.

• Spurling sign (increased radicular pain by extension and lateral bending of the neck toward the side of the lesion)
• L’hermitte sign (feeling of electrical shock with neck flexion)

Dx: Plain x-rays show osteophyte formation, narrowing of disk spaces, and encroachment on the intervertebral foramina.

Tx: A cervical collar to restrict neck movements may relieve severe pain. Pain may also respond to simple analgesics, nonsteroidal anti-inflammatory drugs, muscle relaxants, tricyclic antidepressants (taken at night), or anticonvulsants.

Question 60

UE Radicular syndromes

Answer 60

C5 (C4-C5) – deltoid; bicep reflex

C6 wrist ext; gun numb; brachioradialis reflex

C7 wrist reflex; middle finger; triceps

C8

L4 Quads

L5 Weak toe

S1 gastrocnemius; achilles

Question 61

🔙 BACK PAIN

Answer 61

Trauma: Lifting heavy objects without adequate bracing of the spine can cause
musculoskeletal pain that improves with rest. Clinical examination commonly reveals spasm of the lumbar muscles and restricted spinal movement. Tx: Management includes
local heat, bed rest on a firm mattress, nonsteroidal antiinflammatory drugs or other analgesics, and musclerelaxant drugs.

Lumbar osteoarthropathy: This tends to occur in later life and may cause low back
pain that is increased by activity. MRI is the preferred mode of imaging. Many asymptomatic elderly subjects have degenerative changes of the lumbar spine. In patients with mild symptoms, a surgical corset is helpful, whereas in more severe cases operative treatment may be necessary. Even minor changes may cause root or cord dysfunction in patients with a congenitally narrowed spinal canal (spinal stenosis), leading to the syndrome of intermittent claudication of the spinal cord or cauda equina. Similar symptoms may result from ossification of the ligamentum flavum, epidural lipomatosis, Pott disease, osteomyelitis, rheumatoid arthritis, or post-traumatic stenosis of the spinal canal. The syndrome is characterized by pain, sometimes
accompanied by weakness or radicular sensory disturbances in the legs, that occurs with activity or with certain postures and is relieved by rest. Patients with mild to moderate symptoms related to spinal stenosis should be treated conservatively with pain medication, nonsteroidal anti-inflammatory agents, and physical therapy to reduce the lumbar lordosis. Bed rest is to be avoided. If symptoms are severe, decompressive surgery is indicated when conservative treatment for 3 to 6 months has been unhelpful or there is a significant motor deficit or symptoms of cauda equina syndrome (compression of lumbosacral nerve roots in the spinal canal, below the end of the spinal cord [conus medullaris]).

Ankylosing Spondylitis: Backache and stiffness, followed by progressive limitation
of movement, characterize this disorder, which occurs predominantly in young men. Characteristic early radiologic findings consist of sclerosis and narrowing of the
sacroiliac joints. Treatment is with nonsteroidal antiinflammatory agents, especially indomethacin or aspirin. Physical therapy, including postural exercises, is also important.

Neoplasm: Extradural malignant tumors are an important cause of back pain and should be suspected if there is persistent pain that worsens despite bed rest. Neoplastic disease can also lead to a nonmetastatic (paraneoplastic) sensory or sensorimotor polyneuropathy or to Lambert-Eaton syndrome.

Infection: Tuberculous and pyogenic infections of the vertebrae or intervertebral disks can cause progressive low back pain and local tenderness. Although there are sometimes no systemic signs of infection, the peripheral white cell count and erythrocyte sedimentation rate are elevated; osteomyelitis;

Osteoporosis: Low back pain is a common complaint in patients with osteoporosis, and vertebral fractures may occur spontaneously or after trivial trauma. Pain may be helped by a brace to support the back. It is important that patients keep active, stop tobacco smoking, and take a diet containing adequate amounts of calories, calcium, vitamin D, and protein. Estrogen therapy may be helpful in postmenopausal women, but is less widely used than previously. The bisphosphonates alendronate and risedronate may be helpful and have reduced the incidence of fractures.

Pagets Dz: Paget disease, which is characterized by excessive bone destruction and repair, is of unknown cause but may have a familial basis. The serum calcium and phosphorus levels are normal, but the alkaline phosphatase is markedly increased.

Congenital: Minor spinal anomalies can cause pain because of altered mechanics or alignment or because reduction in the size of the spinal canal renders the cord or roots more liable to compression by degenerative or other changes.

Referred: Disease of the hip joints may cause pain in the back and thighs that is enhanced by activity; examination reveals limitation of movement at the joint with a positive Patrick sign (hip pain on external rotation of the hip), and radiographs show degenerative changes. Aortic aneurysms, cardiac ischemia, visceral and genitourinary disease (especially pelvic disorders in women), and retroperitoneal masses can also cause back pain.

Nonspecific Chronic Back Pain: Nonsteroidal anti-inflammatory drugs may provide
short-term symptomatic relief. There is some controversy about the chronic use of narcotic analgesics in patients with persisting low back pain, but such agents are generally best avoided. Treatment with tricyclic antidepressant drugs is sometimes helpful, and psychiatric evaluation may be worthwhile. Bedrest is not recommended and provides no greater benefit than symptom-limited activity.

Question 62

Referred

Answer 62

Disease of the hip joints may cause pain in the back and thighs that is enhanced by activity; examination reveals limitation of movement at the joint with a positive Patrick sign (hip pain on external rotation of the hip), and radiographs show degenerative changes.

Aortic aneurysms, cardiac ischemia, visceral and genitourinary disease (especially pelvic disorders in women), and retroperitoneal masses can also cause back pain.

Question 63

Neoplasm

Answer 63

Age >50, nocturnal pain, weight loss

Should be suspected if there is persistent pain that worsens despite bed rest.

Dx: Plain film x-rays can be performed quickly and can identify signs of malignant disease, infection, or vertebral compression.

Inflammatory markers (eg, erythrocyte sedimentation rate [ESR], C-reactive protein) can increase sensitivity and are also advised. If the ESR or x-rays are abnormal,

MRI should be done to evaluate for possible cancer or spinal infection. MRI is also indicated for patients with significant neurologic deficits or features of cauda equina syndrome (eg, saddle anesthesia, urine retention)

For patients in whom multiple myeloma is suspected (eg, bone pain, anemia, hypercalcemia, kidney injury), skeletal surveys (including x-rays of chest, spine, skull, and pelvis) are preferred to a bone scan as they better detect the lytic lesions seen in multiple myeloma.

​Cx: Neoplastic disease can also lead to a nonmetastatic (paraneoplastic) sensory or sensorimotor polyneuropathy or to Lambert-Eaton syndrome.

Question 64

⚙ Mechanical

(Lumbosacral strain)

Answer 64

The most common cause of back pain. It is estimated that the lifetime risk of lumbosacral strain is close to 80%.

Hx: The pain starts acutely after physical exertion, and it is concentrated in the lumbar area, usually without radiation to the thighs.

Px: Physical examination reveals local tenderness and contraction of the paraspinal muscles. A straight-leg raising test and neurologic examination are typically normal.

Dx: Imaging for uncomplicated low back pain does not improve outcomes and is NOT recommended. However, patients at risk for infection, malignancy, or bony abnormalities (eg, compression fracture) may require more aggressive or specific intervention and warrant early imaging. These red 🚩flag features include the following:

• Age >50
• History of cancer
• Constitutional symptoms (eg, fever, unexplained weight loss)
• Nocturnal pain
• No response to appropriate treatment
• Significant or progressive neurologic deficits

Tx:

Patients with acute back pain should be advised to continue moderate activity 🏃🏽‍♂️. Extended periods of bed rest or other significant reductions in activity are associated with prolonged pain and stiffness and should be avoided

Nonsteroidal anti-inflammatory drugs may provide short-term symptomatic relief.

❗Opiates: There is some controversy about the chronic use of narcotic analgesics in patients with persisting low back pain, but such agents are generally best avoided.

Some patients who fail to improve with acetaminophen or NSAIDs may benefit from muscle relaxants (eg, cyclobenzaprine, tizanidine).

Tricyclic antidepressants can be useful in the treatment of chronic pain and do serve as adjuvants to other analgesics.

Psychiatric evaluation may be worthwhile.

Question 65

Radiculopathy

Answer 65

Radiculopathies are distinguished from peripheral neuropathies by the distribution of motor or sensory deficits. The presence of neck or back pain that radiates to the extremities in a radicular distribution also suggests a root lesion. Radicular pain is caused most commonly by mechanical root compression from disk protrusion, spinal stenosis, or congenital anomalies.

Hx: The pain is localized to the distribution of one or more nerve roots and is often exacerbated by coughing, sneezing, and other maneuvers that cause increased intraspinal pressure. It is also exacerbated by maneuvers that stretch the affected roots.

Sensory loss or pain, thoracic levels often affected, weakness in distribution of nerve roots.

Px: Passive straight-leg raising leads to stretching of the sacral and lower lumbar roots, as does passive flexion of the neck, or extension and lateral flexion of the head to the affected side.

Tx: Useful modes of treatment for mechanical causes include immobilization, nonsteroidal anti-inflammatory drugs or other analgesics, and surgical decompression.

Epidural steroid injections may be helpful in radicular pain, but are not recommended in uncomplicated back pain or as initial treatment in acute radicular pain.

Question 66

Lumbosacral radiculopathy (sciatica)⚡

Answer 66

Lumbosacral radiculopathy (sciatica)⚡, most likely due to nerve root compression by a prolapsed Interverterbal Disk: Protruded disk material may press on one or more nerve roots and thus produce radicular pain, a segmental motor or sensory deficit, or a sphincter disturbance in addition to a painful stiff back. The pain may be reproduced by percussion over the spine or sciatic nerve, by passive straight leg raising, or by extension of the knee while the hip is flexed. There is local tenderness, and Lasègue sign (reproduction of the patient’s pain on stretching the sciatic nerve by straight leg raising) is positive.

Dx: Magnetic resonance imaging would likely demonstrate the disk herniation and nerve root compression (NOT indicated).

Tx: Symptoms often resolve with simple analgesics, 🧯 Nonsteroidal anti-inflammatory drugs and acetaminophen are the preferred first-line drugs, diazepam, and bed REST on a firm mattress for 2 to 3 days, followed by gradual mobilization.

Fu: Persisting pain, an increasing neurologic deficit, signs of cauda equina syndrome (eg, saddle anesthesia), or concern for epidural abscess (eg, fever, intravenous drug abuse).or any evidence of sphincter dysfunction should lead to MRI, CT scanning, or CT myelography, and surgical treatment if indicated by the results of these procedures.

Question 67

Acute lumbosacral radiculopathy

Answer 67

Acute lumbosacral radiculopathy is usually due to compression of the L5 or S1 nerve roots. With the patient supine, raising the leg with the foot dorsiflexed increases traction on the nerve root and can reproduce the patient’s symptoms (straight leg raise test). Exacerbation of pain with lifting of the opposite leg (crossed straight leg raise) is also strongly consistent with a lumbosacral radiculopathy. L5 lesions cause sensory loss or paresthesias over the anterior leg.

Compression or other disruption of the nerve root can cause radiculopathy and can be due to skeletal (eg, foraminal stenosis) or nonskeletal (eg, infection, tumor) causes. The majority of cases are due to vertebral disc herniation, with disruption of the annulus fibrosus and subsequent prolapse of the nucleus pulposus. Most cases will resolve over several weeks to a few months.

There are eight cervical nerves and seven cervical vertebrae. C1 to C7 cervical nerves exit above their respective vertebrae.

C8 exits below the C7 vertebra and all other spinal nerves exit below their corresponding vertebrae.

Question 68

Trauma

Answer 68

Lifting heavy objects without adequate bracing of the spine can cause musculoskeletal pain that improves with rest.

Px: Clinical examination commonly reveals spasm of the lumbar muscles and restricted spinal movement.

Dx: Vertebral fractures that follow more severe injury and lead to local pain and tenderness can be visualized at radiography. If spinal cord involvement is suspected—for example, because of leg weakness after injury—the patient must be immobilized until imaged to determine whether fracture dislocation of the vertebral column has occurred.

High-risk factors: include age >65 years, dangerous mechanism (including high speed motor vehicle accident) or numbness/tingling in the extremities. A “yes” answer to any of the above requires radiography.

Low-risk factors include a simple rear-end collision, if the patient was ambulatory at any time at the scene, if there was absence of neck pain at the scene, and if there was absence of C-spine tenderness on examination. A “no” answer to any of the above would require radiography.

Is the patient able to voluntarily actively rotate the neck 45° to the left and right regardless of pain? A “no” answer to that question would require radiography.

Tx: Management includes local heat, bed rest on a firm mattress, nonsteroidal antiinflammatory drugs or other analgesics, and musclerelaxant drugs.

Question 69

Lumbar osteoarthropathy

(spinal stenosis)

Answer 69

Caused by narrowing of the spinal canal, leading to compression of one or more spinal roots. It is primarily seen in degenerative arthritis with osteophyte formation affecting the facet joints (spondylosis).

Other factors may contribute, including hypertrophy of the ligamentum flavum, bulging of the intervertebral discs, and spondylolisthesis (displacement of one vertebral body relative to another). Most patients are over age 60.

The symptoms of SS are posture-dependent. Extension of the lumbar spine (eg, standing, walking upright) further narrows the spinal canal and worsens the symptoms, whereas lumbar flexion (eg, walking uphill, leaning on a cane) 🛒 relieves the pain. The onset of pain with walking is referred to as “neurogenic claudication” as it may resemble symptoms seen in vascular claudication. However, vascular claudication causes pain with exertion and relief with rest, whereas neurogenic claudication is relieved by walking while leaning forward (“shopping cart sign”), and exercise with the spine flexed (eg, cycling) does not incite symptoms.

• “Semian gait”
• “Neurogenic claudication”
• “Spinal phalens”

Even minor changes may cause root or cord dysfunction in patients with a congenitally narrowed spinal canal (spinal stenosis), leading to the syndrome of intermittent claudication of the spinal cord or cauda equina.

Similar symptoms may result from ossification of the ligamentum flavum, epidural lipomatosis, Pott disease, osteomyelitis, rheumatoid arthritis, or post-traumatic stenosis of the spinal canal. The syndrome is characterized by pain, sometimes accompanied by weakness or radicular sensory disturbances in the legs, that occurs with activity or with certain postures and is relieved by rest.

Tx: Patients with mild to moderate symptoms related to spinal stenosis should be treated conservatively with pain medication, 🧯 nonsteroidal anti-inflammatory agents, and physical therapy to reduce the lumbar lordosis.

Dx: CT scan

Tx: Decompressive surgery is indicated when conservative treatment for 3 to 6 months has been unhelpful or there is a significant motor deficit or symptoms of cauda equina syndrome: (compression of lumbosacral nerve roots in the spinal canal, below the end of the spinal cord [conus medullaris]).

Bed rest is to be avoided.

Question 70

Spondylolisthesis

Answer 70

Spondylolisthesis is characterized by forward slip of a vertebral body (usually L5) and develops in patients in spondylolysis who have bilateral defects. It is most common during adolescent (age 10-19) growth spurts due to increased physiologic lumbar lordosis (exposing L5 vertebra) and decreased bone mineralization. Athletes with repetitive back extension and rotation (eg, gymnasts, divers) are at greatest risk.

In addition to progressive low back pain, the shifted vertebra can also impinge on the spinal cord and cause radiculopathy (eg, radiating pain, numbness, weakness) in patients with spondylolisthesis.

A palpable step-off at the area of vertebral displacement is characteristic on examination. Spondylolisthesis is typically detected on lumbar radiographs, and symptoms resolve with conservative management (eg, limited activity, physical therapy, analgesics) in most cases. Persistent pain, progressive vertebral displacement, or neurologic abnormalities (eg, weakness, incontinence) require surgical evaluation.

Question 71

Epidural Spinal cord compression (ESCC)

Answer 71

Causes

• Spinal injury (eg, motor vehicle crash)
• Malignancy 🦀 (eg, lung, breast, prostate cancers; myeloma)
• Infection (eg, epidural abscess)

Signs & symptoms

• Gradually worsening, severe local back pain
• Pain worse in the recumbent position/at night 🌛
• Early signs: Symmetric lower extremity weakness, hypoactive/absent deep-tendon reflexes
• Late signs: Bilateral Babinski reflex, decreased rectal sphincter tone, paraparesis/paraplegia with increased deep-tendon reflexes, sensory loss ⚡

Motor findings (bilateral weakness) and ataxia are common as the disease progresses. Bowel and bladder dysfunction are late finding

Management

• ❗ Emergency MRI
• Intravenous glucocorticoids 🌑
• Radiation-oncology & neurosurgery consultations

🦀Cancers that often metastasize to the spine include lung, breast, and prostate, as well as multiple myeloma.

Although imaging (MRI) plays an important role in the diagnosis of ESCC, intravenous glucocorticoids should be given without delay in a patient with suspected ESCC. 🌑Glucocorticoids decrease vasogenic edema (caused by obstructed epidural venous plexus), help alleviate pain, and may restore neurologic function. Once imaging confirms ESCC, neurosurgical consultation is typically required.

Acute spinal cord compression (SCC) is characterized by injury to the following:

Descending corticospinal tracts (lower-extremity weakness and loss of rectal tone)

Ascending sensory spinothalamic tracts (the sensory level is often 2 spinal cord segments below the level of lesion)

Descending autonomics in the reticulospinal tract (urinary retention/bladder flaccidity/bladder shock)

Question 72

Spinal epidural abscess (SEA)

Answer 72

Spinal epidural abscess (SEA) is a rare infection of the epidural space that may threaten the spinal cord and result in paralysis. Most cases are due to hematologic spread from a distant infection (eg, cellulitis, bone/joint), intravenous drug use, or direct inoculation during a spinal procedure. Staphylococcus aureus is the most common (65%) causative organism.

SEA classically results in the triad of fever (50%), back pain, and neurologic deficits; however, all 3 symptoms are present in a minority of cases. Most patients initially develop severe, focal back pain that progresses over days to nerve root pain (“shooting/electric”) and more severe neurologic manifestations (motor weakness, sensory changes, bowel/bladder dysfunction, paralysis).

The diagnostic test of choice is MRI of the spine due to high sensitivity early in the course of illness and excellent localization of infection extent. Treatment with broad- spectrum antibiotics and aspiration/surgical decompression is usually required.

Question 73

Osteoporosis

Answer 73

Low back pain is a common complaint in patients with osteoporosis, and vertebral fractures may occur spontaneously or after trivial trauma.

Dx: Osteoporosis is diagnosed by a DEXA T-score of less than –2.5 or the presence of fragility fractures; a fragility fracture (fracture sustained in a fall from a standing height) defines osteoporosis regardless of bone mineral density results.

T-score (the number of standard deviations above or below the mean matched to
YOUNG controls).

Z-score (the number of standard deviations above or below the mean-matched to age-matched controls).

Tx: The National Osteoporosis Foundation (NOF) recommends antiosteoporotic therapy for persons whose risk of major osteoporotic fracture over the next 10 years is 20% or greater or whose risk of hip fracture over the next 10 years is 3% or greater.

Vitamin D increases absorption of calcium in the GI tract.

Brace to support the back. It is important that patients keep active, stop tobacco smoking, and take a diet containing adequate amounts of calories, calcium, vitamin D, and protein. Recommended activities include walking, jogging, weight lifting, aerobics, stair climbing, field sports, racquet sports, court
sports, and dancing. Swimming is questionable, as it is not weight-bearing.

Estrogen works by blocking the activity of cytokines. Estrogen therapy may be helpful in postmenopausal women, but is less widely used than previously.

Raloxifene or Evista, a selective estrogen receptor modulator, is also approved for osteoporosis prevention by the FDA. However, vasomotor symptoms are highly associated with its use.

Calcitonin directly inhibits osteoclastic bone resorption and is considered a reasonable treatment alternative for patients with established osteoporosis in whom estrogen-replacement therapy is not recommended. It has the unique characteristic of producing an analgesic effect
with respect to bone pain and is often prescribed for patients who have suffered an acute osteoporotic fracture.

Bisphosphonates: Alendronate is approved for both osteoporosis prevention and treatment by the Food and Drug Administration (FDA).

Zoledronic acid (IV bisphosphonate) is preferred for women with postmenopausal osteoporosis who are unable to take oral bisphosphonates (gastroesophageal reflux disease) or who desire the convenience of less frequent dosing.

Teriparatide, or recombinant human parathyroid hormone (1-34), is an anabolic agent that increases bone density and decreases fracture risk. However, it is considered second-line therapy to bisphosphonates, is expensive, and has been associated with an increased risk of osteosarcoma.

Cx: Vertebral compression fracture (VCF)The most common cause of nontraumatic VCF is osteoporosis, which is characterized by progressive loss of bone mineral density and loss of normal bony architecture. VCF can also be due to osteomalacia, which is usually caused by inadequate levels of vitamin D, calcium, or phosphorus and results in decreased bone mineralization and increased fracture risk. Other risk factors for VCF include trauma, infection (eg, osteomyelitis), malignancy with bone metastases, and metabolic abnormalities (eg, hyperparathyroidism).

Question 74

Cauda equina syndrome

Answer 74

Cauda equina syndrome typically results from a massive rupture of an intervertebral disk that is capable of causing compression of two or more of the 18 spinal nerve roots of the cauda equina. However, it can also occur due to any trauma or space-occupying lesion of the lower vertebral column. The cauda equina nerve roots provide the sensory and motor innervation of most of the lower extremities, the pelvic floor, and the sphincters.

Hx: Classic symptoms of cauda equina syndrome include low back pain radiating to one or both legs, (asymmetric) 🐎saddle anesthesia, loss of anocutaneous reflex, (late) bowel and bladder dysfunction (S3-S5 roots), and loss of ankle-jerk reflex with plantar flexion weakness of the feet.

Positive straight leg raise testing (worsened sciatic pain when straight leg is raised to 30-70 degrees) is positive in >90% of those with acute lumbar herniation and may aid diagnosis.

Dx: Confirmation requires urgent MRI of the lumbosacral spine.

Tx: Because patients with CES (particularly in the setting of bladder or rectal dysfunction) are at high risk for permanent neurologic sequelae, surgical decompression is then usually necessary.

Question 75

Conus medullaris syndrome

Answer 75

Conus medullaris syndrome refers to lesions at L2.

It has symptoms of (early) flaccid paralysis of the bladder and rectum 💩, impotence, and (symmetric) 🐎saddle (S3-S5 roots) anesthesia. There is usually mild weakness of the leg muscle if the lesion spares both the lumbar cord and the adjacent spinal and lumbar nerve roots. Common causes include disk herniation, tumors, and spinal fractures.

Question 76

Ankylosing spondylitis

Answer 76

Male predominance, and the peak age of onset is between 20 and 30 years.

Hx: Patients classically present with progressive inflammatory back pain and stiffness. Initially, pain can be localized to the low back, buttocks, or posterior thighs. With time, inflammation and bony changes usually ascend the spine, producing a stooped posture with limited mobility of the spine and chest.

Dx: Elevation of systemic inflammatory markers such as erythrocyte sedimentation rate or C-reactive protein. A single AP radiograph of the pelvis provides a view of the sacroiliac joints and the hips and is indicated for patients with suspected spondyloarthritis. The earliest changes typically occur at the iliac portion of the sacroiliac joint where the subchondral bone becomes less distinct. Erosive changes can subsequently produce irregularity of the cortex. Computed tomography (CT) can detect erosive or sclerotic changes when plain radiographs are insufficient; however, MRI is preferred for the detection of active inflammation and does not expose patients to the radiation of CT.

Question 77

Paget disease

Answer 77

Paget disease, which is characterized by excessive bone destruction and repair, is of unknown cause but may have a familial basis. The serum calcium and phosphorus levels are normal, but the alkaline phosphatase is markedly increased.

Question 78

Diffuse idiopathic skeletal hyperostosis (DISH)

Answer 78

A bony hardening of ligaments in areas where they attach to your spine.

Px: Loss of range of motion.

Question 79

Asymptomatic

Answer 79

A moderately elevated serum uric acid level without evidence of symptoms of gout.

Patients with asymptomatic hyperuricemia have an increased risk for gout over the long term but a low likelihood of a gout attack in the short term; thus, a pharmacologic intervention is not indicated.

Question 80

BONE

Question 81

Slipped capital femoral epiphysis (SCFE)

Answer 81

Risk factors

• Obesity
• Adolescence

Clinical presentation

• Dull hip pain
• Referred knee pain
• Altered gait
• Limited internal rotation of hip

Diagnosis

• Posteriorly displaced femoral head on x-ray

Treatment

• Non–weight bearing
• Surgical pinning

Complications

• Avascular necrosis
• Osteoarthritis

Slipped capital femoral epiphysis (SCFE) is characterized by anterolateral and superior displacement of the proximal femur along the physis (growth plate). It most commonly presents in obese adolescents with ⌛chronic (>3 weeks) hip pain. However, 15% of patients with SCFE have only referred thigh or knee pain. Due to the referred nature of the pain, knee examination is normal. Characteristic findings on hip examination, however, include limited internal rotation, which causes the foot to point laterally 🦵, and thigh abduction and external rotation with passive hip flexion.

Dx: Bilateral hip x-rays are diagnostic for SCFE and show a posteriorly displaced femoral head. The patient should be non–weight bearing to avoid further slip and referred for immediate surgical screw fixation of the physis.

Question 82

Osgood-Schlatter disease (osteochondritis of the tibial tubercle)

Answer 82

Osgood-Schlatter disease, or osteochondritis of the tibial tubercle, is a common cause of chronic knee pain that is worse with running and jumping in active adolescents. Tenderness over the tibial tubercle would be present on examination

Causes pain at the insertion of the patellar tendon. It usually occurs in adolescent and preadolescent patients and frequently follows a rapid growth spurt. X-ray may show avulsion of the tubercle, but the femur is normal.

Question 83

Osteosarcoma

Answer 83

Most cases occur in a bimodal distribution, as follows:

• In children and adolescents, osteosarcoma usually develops at the metaphysis of long bones, where cellular turnover is high (primary osteosarcoma).
• In adults age >40, osteosarcoma usually develops at sites of damaged bone, particularly due to Paget disease of bone, irradiation, or prior benign bone tumor (secondary osteosarcoma).

Occurs most commonly in the second decade of life, and a bit more commonly in boys than in girls. It occurs in all ethnic groups (in contrast, Ewing sarcoma, another bone malignancy, rarely occurs in blacks).

Predisposing factors include a history of retinoblastoma, Li-Fraumeni syndrome, Paget disease, or radiotherapy. Any bone or joint “injury” not responding with conservative therapy within a short period of time should be evaluated.

Manifestations of malignant transformation generally include worsened localized pain and soft tissue swelling. Imaging usually shows a destructive bone lesion with a mixture of radiodense and radiolucent areas, a sunburst periosteal pattern, and/or Codman triangle (periosteal elevation). Adults who develop osteosarcoma have a poor prognosis.

Question 84

Giant cell tumor of bone (GCTB)

Answer 84

GCTB is a benign but locally destructive neoplasm that is most common at the epiphysis of long bones. The incidence is highest in young adults who have reached skeletal maturity, but it can also occur in older adults, typically associated with Paget disease of bone. The course is variable; most patients have only local manifestations (eg, pain, swelling, stiffness, pathologic fracture), but pulmonary metastasis and malignant transformation may occur.

X-ray in GCTB characteristically shows an eccentric lytic lesion, which is often described as resembling 🧼soap bubbles. CT imaging can show greater detail of the mass, and MRI is often indicated to visualize the adjacent soft tissues. The diagnosis is confirmed with biopsy, which shows multinucleated giant cells resembling osteoclasts interspersed with sheets of mononuclear stromal cells.

Tx: Surgery (eg, intralesional curettage or excision) is first-line treatment. Monoclonal antibodies (eg, denosumab) against the receptor activator of nuclear factor kappa-B ligand (RANKL), which is overexpressed in the stromal cells, can also be used to shrink the tumors.

Question 85

🤡 Langerhans cell histiocytosis

Answer 85

Clinical findings

• Lytic bone lesions (eg, skull, jaw, femur)
• Skin lesions (purplish papules, eczematous rash 🤡)
• Lymphadenopathy, hepatosplenomegaly
• Pulmonary cysts/nodules
• Central diabetes insipidus

Diagnosis

• Langerhans cells on bone/skin biopsy

Treatment

• Chemotherapy (prednisone ± vinblastine)
• Desmopressin for diabetes insipidus

LCH is a rare disorder in which histiocytes (macrophages within tissue) proliferate and infiltrate one or more organ systems. Bone is most commonly affected, but invasion of the skin (eczematous rash), lymph nodes, lungs (cough, pulmonary nodules), liver, spleen, and CNS (central diabetes insipidus with polyuria and hypernatremia) can also occur.

Bone lesions are frequently found in the skull; the femur, vertebrae, and other bones can also be affected. Lesions may be asymptomatic or associated with local pain and an overlying tender mass. X-ray shows characteristic “punched-out” lytic lesions; biopsy is required to confirm the diagnosis.

Although the bone tumors are benign, they can be locally destructive and are typically treated with curettage or chemotherapy (eg, prednisone).

Question 86

Myopathy

Answer 86

Connective tissue diseases

• Polymyositis/dermatomyositis
• Inclusion body myositis
• Vasculitis
• Overlap syndrome (mixed connective tissue disease)

Endocrine/metabolic

• Hypothyroidism, thyrotoxicosis
• Cushing syndrome
• Electrolytes (↓ potassium, calcium, phosphorus)

Drugs/toxins

• Corticosteroids, statins
• Zidovudine, colchicine
• Alcohol, cocaine, heroin

Miscellaneous

• Infections, trauma, hyperthermia

Myopathy occurs in over one third of patients with hypothyroidism, and can range from an asymptomatic elevation in CK to myalgias, muscle hypertrophy, proximal myopathy, and rhabdomyolysis. Serum CK can be elevated for years before a patient develops clinical symptoms of hypothyroidism, and there is no clear correlation between the degree of CK elevation and severity of muscle disease. Inflammatory markers (eg, erythrocyte sedimentation rate, C-reactive protein) may be normal or mildly elevated. Initial testing should include TSH and free T4. If thyroid studies are normal, additional testing, including serologic markers (eg, antinuclear antibodies, anti-Jo-1 antibodies) and muscle biopsy, may be needed to rule out other causes of myositis.

Question 87

Metabolic Myopathies

Answer 87

Hypokalemia: Proximal myopathic weakness may result from chronic hypokalemia, and once the metabolic disturbance has been corrected, power usually returns to normal within a few weeks.

Periodic Paralyses:

In the hypokalemic form, sometimes associated with thyrotoxicosis,
attacks tend to occur on awakening, after exercise, or after a heavy meal, alcohol consumption, or exposure to cold, and may last for several days. Acetazolamide (250-750 mg daily) or oral potassium supplements may prevent attacks, as also may a low salt and low carbohydrate diet.

Attacks associated with hyperkalemia also tend to come on after exercise but are usually much briefer, lasting less than 1 hour. Severe attacks may be terminated by intravenous calcium gluconate (1-2 g), intravenous diuretics (furosemide 20-40 mg), or glucose, and daily acetazolamide or chlorothiazide may help prevent further episodes.

Normokalemic: This disorder is similar clinically to the hyperkalemic variety, but the plasma potassium level is normal in attacks; treatment is with acetazolamide.

Question 88

Fibromyalgia (FM)

Answer 88

FM occurs most commonly in young to middle-aged women and presents with widespread pain, fatigue, and cognitive/mood disturbances. Patients have a fairly normal physical examination except for trigger point tenderness in areas such as the mid trapezius, lateral epicondyle, costochondral junction, and greater trochanter. Patients perceive that their pain and fatigue worsen acutely after exercise, although a regular, incremental, low-impact exercise regimen (eg, fast walking, swimming, water aerobics) can improve pain and provide long-term benefit.

The diagnosis of FM is primarily based on history and examination findings. Revised 2010 American College of Rheumatology criteria suggest using the widespread pain index and symptom severity score for diagnosis, as these reflect the cognitive and somatic symptoms of the disorder better than criteria based on trigger points. Laboratory tests, including inflammatory (eg, erythrocyte sedimentation rate, C-reactive protein [CRP]) and serologic (eg, rheumatoid factor, antinuclear antibody) markers, are typically normal.

Question 89

Fibromyalgia

Answer 89

Fibromyalgia is characterized by widespread pain and tenderness of at least 3 months’ duration.

Hx: Youg to middle-aged woman.

Chronic widespread pain

Fatigue, Impaired concentration

Px: Tenderness at trigger points

Dx: > 3 months of symptoms with widespread pain index or symptom severity score

Normal labs

Tx: serotonin-norepinephrine reuptake inhibitor (SNRI)

Question 90

Idiopathic Inflamatory myopathies (Polymyositis/Dermatomyositis/IBM)

Answer 90

Hx: Proximal muscle weakness

Physical exam: Heliotrope rash, shawl sign, grotons papules (hyperkeratotic red papules and plaques over bony prominences), rash (heliotrope rash on the upper eyelids and periorbital area, photosensitive rashes involving the shoulders, neck, and anterior chest)

Labs: elevated CK, EMG,Biopsy, Anti Mi/Jo

Dermatomyositis: CD4-positive T cells around the muscle fascicles and in the perimysial areas.

Tx: Steroids

Question 91

Dermatomyositis (DM)

Answer 91

A systemic autoimmune disease characterized by Myopathy: proximal muscle weakness (eg, difficulty climbing stairs, combing hair), elevated muscle enzymes (eg. Creatinine kinase, aldolase) resembling polymyositis, but with additional inflammatory skin findings: heliotrope rash (erythematous or violaceous edematous eruption on the upper eyelids and periorbital skin) Gottron’s papules (raised erythematous plaques over the joints and bony prominences of the hands). Muscle biopsy is diagnostic and shows mononuclear perimysial infiltrates, perifascicular atrophy, and patchy necrosis.

Cx: 🦀Dermatomyositis may occur alone or as a paraneoplastic syndrome of an underlying malignancy. The most commonly associated cancers include ovarian, lung, colorectal, and non-Hodgkin lymphoma. Symptoms may precede the diagnosis of malignancy but often parallel the course of the cancer.

Causal mechanism is immunologic, with autoantibody production of anti-Mi2, anti-Jo1, or anti-SRP. The condition is often due to underlying bronchogenic, gastric, or colorectal carcinoma.

Antinuclear antibody titers are frequently elevated in dermatomyositis, although anti-Jo-1 is more specific. Muscle biopsy confirms the diagnosis and shows a perimysial inflammatory infiltrate, patchy ischemia and necrosis, and perifascicular atrophy and fibrosis.

Dermatomyositis: CD4-positive T cells around the muscle fascicles and in the perimysial areas.

Question 92

Still Disease

Answer 92

Hx: Systemic inflammatory disorder characterized by quotidian (daily) fever, evanescent rash, arthritis, and multisystem involvement.

Dx: Based on the typical clinical presentation and exclusion of infection and malignancy, particularly leukemia and lymphoma.

Leukocytosis, anemia, thrombocytosis, elevated erythrocyte sedimentation rate, elevated serum ferritin level (≥1000 ng/mL [1000 µg/L]), and abnormal liver chemistry tests; antinuclear antibody titer and rheumatoid factor typically are negative.

Question 93

Systemic sclerosis (scleroderma)

Answer 93

Limited Cutaneous Systemic Sclerosis (CREST)

• Calcinosis (High BP vessel disease)
• Raynaud’s
• Esophageal
• Sclerodactyly
• Telangectaias (GI bleeds, Iron deficiency anemia)

Dx: Anti-centromere antibodies

Cx: Pulmonary arterial hypertension (PAH) is also common in the limited cutaneous subtype of SS. PAH results from intimal (smooth muscle layer) hyperplasia of the pulmonary arteries and typically presents with progressive dyspnea. Patients may also experience exertional syncope or presyncope (eg, lightheadedness) due to right ventricular (RV) failure and inadequate venous return to the left atrium. Px: Demonstrates RV heave (or parasternal heave), which is an impulse palpated immediately to the left of the sternum that suggests RV enlargement. A loud pulmonary component of the second heart sound and signs of right heart failure (eg, peripheral edema, hepatomegaly) may also be present.

Diffuse Cutaneous Systemic Sclerosis

• CREST ➕ Visceral Involvement
• Lung (ILD, DPLD)
• Heart (Constrictive pericarditis)
• Kidney (renal crisis)

Dx: Anti-topoisomerase/Scl70

Cx: Scleroderma renal crisis (SRC) can occur in up to 20% of patients with diffuse cutaneous systemic sclerosis (SSc). SRC usually occurs within the first 5 years of SSc diagnosis. The likely mechanism involves increased vascular permeability, activation of the coagulation cascade, and increased renin secretion. Patients typically develop sudden onset of renal failure (without previous kidney disease), and malignant hypertension (eg, headache, blurry vision, nausea). Urinalysis can be normal or show mild proteinuria. Peripheral blood smear can show microangiopathic hemolytic anemia (similar to hemolytic uremic syndrome/thrombotic thrombocytopenic purpura) or disseminated intravascular coagulation with fragmented red blood cells (eg, schistocytes) and thrombocytopenia. Tx: ACE

Question 94

🦋 Systemic lupus erythematosus (SLE)

Answer 94

Autoantibodies can take the form of immune complexes that deposit in tissues or bond to target cells.

Can cause damage by fixing complement on the surface of a cell (causing cell lysis), by binding to Fc receptors on circulating cells (leading to cell clearance in the liver or spleen), or by binding to Fc receptors on macrophages (initiating cell-mediated inflammation).

Hx: Most common in women of childbearing age; women are 9 times more likely than men to be affected by SLE. Environmental influences (eg, ultraviolet [UV] light), infection by the Epstein-Barr virus, smoking, stress, and hormonal factors likely contribute to SLE development or disease flares.

The most common agents associated with drug-induced lupus are procainamide, hydralazine, isoniazid, and quinidine.

Nonspecific constitutional symptoms are common in SLE and include fatigue, fever, and weight loss. Mucocutaneous findings, such as nasal and oral ulcers, alopecia, or rash (malar or discoid) are found in up to 90% of patients with lupus. Additionally, greater than 90% of patients with SLE have polyarthralgias or polyarthritis. Symmetric wrist or hand (metacarpophalangeal [MCP], proximal interphalangeal [PIP] joints) involvement is most common.

SLE is associated with Raynaud phenomenon, which is characterized by the fingers or toes becoming white or blue when cold and then red when warmed. SLE is also associated with Sjögren syndrome, as evidenced by dry eyes and dry mouth.

ANA is found in 95% to 99% of patients with SLE but lacks specificity. ANA also is found in patients with viral and bacterial infections, other autoimmune diseases, malignancies, and cirrhosis and in up to 10% of the normal population

Dx: A patient is classified as having SLE if 4 of the 11 American College of Rheumatology criteria for SLE diagnosis are confirmed by a physician: To establish the diagnosis of SLE, patients need not manifest all the diagnostic criteria simultaneously; the criteria can be fulfilled over time.

Malar rash

Fixed erythema, flat or raised, over the malar eminences (spare the nasolabial folds and under the lower lip)

Discoid rash

Erythematous, circular, raised patches with keratotic scaling and follicular plugging; atrophic scarring may occur (commonly occur on the external ear, forearm, and scalp; scalp lesions may cause alopecia).

Photosensitivity

Rash after exposure to ultraviolet light

Oral ulcers

Oral and nasopharyngeal ulcers (observed by physician)

Arthritis

Nonerosive arthritis of ≥2 peripheral joints, with tenderness, swelling, or effusion (Tendon inflammation may lead to joint rupture or Jaccoud arthropathy).

Serositis

Pleuritis or pericarditis (documented by electrocardiogram, rub, or evidence of effusion)

Kidney disorder

A patient satisfies this criterion by having a 24-hour urine protein excretion >500 mg/d, (or 3+ protein) by urinalysis showing >10 erythrocytes per high-power field or erythrocyte or leukocyte casts in a sterile urine sample (proven by culture), or by kidney biopsy. Urinalysis: or >0.5 g/d; cellular casts;

Neurologic

Neurologic deficits, seizures, or confusion may indicate central nervous system infection, ischemia, brain or spinal cord inflammation (cerebritis or transverse myelitis), or the more subtle neuropsychiatric manifestations. Sensory or motor symptoms may be due to peripheral neuropathy, muscle inflammation, or ischemia caused by vasculitis.

Hematologic

Anemia is most often due to chronic disease, but can also occur as a result of autoimmune hemolytic anemia (AIHA)​. Cytopenias: leukopenia (<4000/µL) or lymphopenia (<1500/µL ) or thrombocytopenia (<100,000/µL) in the absence of offending drugs. Idiopathic thrombocytopenic purpura (ITP) may be the first presenting symptom of SLE. Evans syndrome, which is the occurrence of two or more immune-mediated cytopenias (usually AIHA and ITP), may also be a manifestation of SLE.

Immunologic

Anti–double-stranded DNA, anti-Smith, and/or antiphospholipid antibodies

Antinuclear antibodies (ANA)

An abnormal titer of ANA by immunofluorescence or an equivalent assay at any point in the absence of drugs known to induce ANA

Dx: Patients with a high pretest probability of SLE and positive ANA assay (usually a titer ≥1:160) should undergo confirmatory testing using a more specific autoantibody study with either an anti-dsDNA antibody assay or an anti-Smith antibody assay. Anti-dsDNA antibodies are present in approximately 50% to 70% of patients with SLE and generally are not found in those with other autoimmune diseases. Patients with a new diagnosis of SLE should also undergo screening for anticardiolipin antibodies and the lupus anticoagulant.

In active SLE, the circulating immune complexes activate complement, causing their consumption and resulting in a decrease of C3, C4, and total hemolytic complement (CH50).

Antiphospholipid syndrome can be associated with SLE or can occur in isolation. Diagnosis includes both clinical and laboratory criteria.

Hx: Antiphospholipid syndrome is associated with venous thromboembolism (59%), arterial thromboembolism (28%), pregnancy loss, vasculitis, and cardiac valvular abnormalities.

Dx: May be initially considered when a patient has unexplained thrombocytopenia or the activated partial thromboplastin time (aPTT) is prolonged and does not improve with a mixing study. Positive anticardiolipin antibodies (IgG or IgM) or lupus anticoagulant in the setting of previous arterial or venous thromboembolism or pregnancy morbidity make the diagnosis of antiphospholipid syndrome.

Lupus nephritis: hypertension, ankle edema, hematuria, proteinuria, and erythrocyte casts on urinalysis

To prevent irreversible kidney damage, early treatment with a high-dose glucocorticoid is indicated for patients whose condition raises strong suspicion for lupus nephritis.

Tx: Musculoskeletal complaints: Methotrexate or, occasionally, low-dose glucocorticoids may be necessary if a patient fails to respond to initial therapies or the initial manifestations are more severe. should be treated with NSAIDs or hydroxychloroquine.

Photosensitive rashes can be treated conservatively with a sunscreen that blocks UVA and UVB radiation, hydroxychloroquine, and topical glucocorticoids.

High-dose or pulse-dose (high doses over a short period of time) glucocorticoids (such as methylprednisolone) or other immunosuppressive agents (eg, cyclophosphamide, mycophenolate mofetil, azathioprine) are used for the more severe manifestations of SLE, including nephritis, cerebritis, vasculitis, and life-threatening hematologic abnormalities.

Cyclophosphamide is generally reserved for lupus nephritis, given its serious side effect profile. Recent studies suggest that mycophenolate mofetil is effective for lupus nephritis with a more favorable side effect profile.

Because patients with SLE may have functional asplenia, vaccination against pneumococcal illness, Haemophilus influenzae infection, influenza, and, possibly, meningococcal infection is indicated.

Patients with SLE and positive antiphospholipid antibodies should be treated with low-dose aspirin (81 mg daily).

Question 95

Antiphospholipid syndrome (APS)

Answer 95

APS presents with a thrombotic event (deep venous thrombus or arterial thrombus) or pregnancy morbidity (fetal loss, severe preeclampsia, placental insufficiency) plus a positive serology for 1 of 3 antiphospholipid antibodies: anticardiolipin antibody, anti-beta2-glycoprotein-I antibody, or lupus anticoagulant.

The biggest risk factor for APS is SLE; APS occurs in up to 40% of these patients.

A minority of healthy individuals may develop transient antiphospholipid antibodies, so all positive serology for APS should be repeated at 12 weeks to confirm diagnosis. Patients with APS often require anticoagulation for life (heparin product or warfarin) as the risk of recurrent thrombus is high. For those with concomitant SLE, hydroxychloroquine is also added.

Question 96

Sjogrens syndrome

Answer 96

Sjögren syndrome is characterized by sicca syndrome, which causes xerophthalmia (dry eyes), and xerostomia (dry mouth). The absence of oral mucosal moisture often causes difficulty with mastication and swallowing and increases the risk for dental caries and periodontal disease. Vaginal dryness and parotid gland enlargement are frequently present, and mild fatigue and arthralgia are common.

Dx: Abnormal findings on the Schirmer test, which measures moisture under the lower eyelids, are consistent with Sjögren syndrome.

Approximately 50% of patients with this syndrome are antinuclear antibody positive and 60% to 75% of patients with primary Sjögren syndrome are anti-Ro/SSA antibody positive, and approximately 40% of these patients are anti-La/SSB antibody positive.

Question 97

Mixed connective tissue disease (MCTD)

Answer 97

A systemic autoimmune condition with clinical features of SLE, systemic sclerosis, and polymyositis. Patients may present with joint pain (arthralgia), myalgias, pleurisy, esophageal dysmotility, and Raynaud’s phenomenon (vasospasm of distal extremities in response to cold temperatures). Because there is overlap of clinical features, it is suggested that the disease is not a distinct entity, but rather a subset of SLE, systemic sclerosis, and polymyositis. Over time, patients with MCTD may progress to the SLE or systemic sclerosis.

One distinguishing feature of this disease is high antibody titers to U1-ribonucleoprotein (RNP), which is involved in splicing machinery. Elevated titers of RF and ANA are also common in MCTD, but non-specific. MCTD is readily treatable with corticosteroid therapy.

Pulmonary hypertension is a common cause of death in MCTD. Unlike in systemic sclerosis, pulmonary hypertension in MCTD is not due to fibrosis of the lungs, but by intimal proliferation and medial hypertrophy of pulmonary arterioles.

In MCTD, renal involvement is uncommon – unlike in SLE, systemic sclerosis, and polymyositis.

Question 98

Antineutrophil cytoplasmic antibodies (ANCAs)

Answer 98

are circulating antibodies that react with cytoplasmic antigens, and were previously classified according to their intracellular distribution: cytoplasmic (c-ANCA) or perinuclear (p-ANCA). They are now named according to their target antigen:

Anti-myeloperoxidase (MPO-ANCA, formerly p-ANCA) targets the lysosomal granule involved in oxygen free radical generation

Anti-proteinase-3 (PR3-ANCA, formerly c-ANCA) PR3 is a neutrophil granule constituent.

Question 99

🍖 MSK

Question 100

Legg-Calvé-Perthes disease

Answer 100

Pathogenesis

• Idiopathic avascular necrosis of the femur

Clinical features

• Boys age 3-12
• Insidious hip pain, limp
• Restricted hip abduction, internal rotation
• Positive Trendelenburg sign

Diagnosis

• X-ray
  
  • Early stages: May be normal
  • Later stages: Femoral head flattening,
  • fragmentation, sclerosis
• MRI: Avascular/necrotic femoral head

Treatment

• Non–weight bearing
• Splinting, possible surgical repair

LCP classically affects boys age 3-12, with peak incidence at age 6.

Patients typically have an antalgic gait (avoids weight bearing on the affected side due to pain) and dull, chronic lower extremity pain of insidious onset. The pain may affect the hip directly or present as referred thigh or knee pain. Diagnosis requires a high index of suspicion as initial x-rays may be normal. Persistent symptoms should prompt repeat imaging, which in later stages typically shows sclerosis of the femoral head with flattening and fragmentation. As the disease progresses, examination may reveal limited internal rotation and abduction of the hip.

Proximal thigh atrophy and Trendelenburg sign may also be present.

Treatment is aimed at maintaining the femoral head within the acetabulum by avoiding weight-bearing activities and by splinting or surgery.

Question 101

Slipped capital femoral epiphysis (SCFE)

Answer 101

Risk factors

• Obesity
• Adolescence

Clinical presentation

• Dull hip pain
• Referred knee pain
• Altered gait
• Limited internal rotation of hip

Diagnosis

• Posteriorly displaced femoral head on x-ray

Treatment

• Non–weight bearing
• Surgical pinning

Complications

• Avascular necrosis
• Osteoarthritis

Slipped capital femoral epiphysis (SCFE) is characterized by anterolateral and superior displacement of the proximal femur along the physis (growth plate). It most commonly presents in ⚪obese adolescents with chronic ⌛ (>3 weeks) hip pain. However, 15% of patients with SCFE have only referred thigh or knee pain. Due to the referred nature of the pain, knee examination is normal. Characteristic findings on hip examination, however, include limited internal rotation, which causes the foot to point laterally, and thigh abduction and external rotation with passive hip flexion.

SCFE most commonly presents in obese adolescents (age 10-16) with limp and chronic pain/ache of the hip, thigh, or knee that worsens with activity 🏃🏽‍♂️. Patients with unilateral SCFE may have an antalgic gait to avoid bearing weight on the affected leg whereas patients with bilateral SCFE often develop a waddling gait. Feet are pointed laterally due to limited internal rotation of the affected hip, and external rotation of the thigh during passive hip flexion is a characteristic examination finding.

Bilateral hip x-rays are diagnostic for SCFE and show a posteriorly displaced femoral head. The patient should be non–weight bearing to avoid further slip and referred for immediate surgical screw fixation of the physis.

Question 102

Osgood-Schlatter disease (osteochondritis of the tibial tubercle)

Answer 102

Osgood-Schlatter disease, or osteochondritis of the tibial tubercle, is a common cause of chronic knee pain that is worse with running and jumping in active adolescents.

Px: Tenderness over the tibial tubercle

Question 103

Osteoid osteoma

Answer 103

Epidemiology

• Benign, bone-forming tumor
• Most common in adolescent boys

Clinical features

• Proximal femur most common site
• Pain
• Worse at night
• Relieved by NSAIDs
• Unrelated to activity
• No systemic symptoms

X-ray findings

• Small, round lucency

Treatment

• NSAIDs

Monitor for spontaneous resolution

Osteoid osteoma is a benign, bone-forming tumor that typically occurs in adolescent boys. The femur (particularly the proximal bone), tibia, and spine are the most common sites affected. Patients develop increasing pain that is worse at night and is unrelated to physical activity. Pain relieved by nonsteroidal anti-inflammatory drugs (NSAIDs) is a classic feature that is strongly suggestive of the diagnosis; the absence of this finding should raise suspicion for alternate diagnoses.

Tenderness, deformity, or swelling may be present on examination; however, adolescents may have no focal examination findings. X-ray shows a characteristic small, round lucency with sclerotic margins and sometimes central ossification. NSAIDs are prescribed for symptomatic relief, and serial imaging is performed to monitor the lesion. Surgical resection is typically reserved for patients with refractory symptoms, as most lesions resolve spontaneously over several years.

Question 104

Osteosarcoma

Answer 104

Most cases occur in a bimodal distribution, as follows:

• In children and adolescents, osteosarcoma usually develops at the metaphysis of long bones, where cellular turnover is high (primary osteosarcoma).
• In adults age >40, osteosarcoma usually develops at sites of damaged bone, particularly due to Paget disease of bone, irradiation, or prior benign bone tumor (secondary osteosarcoma).

Occurs most commonly in the second decade of life, and a bit more commonly in boys than in girls. It occurs in all ethnic groups (in contrast, Ewing sarcoma, another bone malignancy, rarely occurs in blacks).

Predisposing factors include a history of retinoblastoma, Li-Fraumeni syndrome, Paget disease, or radiotherapy. Any bone or joint “injury” not responding with conservative therapy within a short period of time should be evaluated.

Manifestations of malignant transformation generally include worsened localized pain and soft tissue swelling. Imaging usually shows a destructive bone lesion with a mixture of radiodense and radiolucent areas, a sunburst periosteal pattern, and/or Codman triangle (periosteal elevation). Adults who develop osteosarcoma have a poor prognosis.

Question 105

Ewing sarcoma

Answer 105

Ewing sarcoma typically presents in the pelvis or long-bone diaphyses (eg, femur) with pain and swelling. Pain is generally worse with activity and does not respond to NSAIDs. X-ray shows extensive bony involvement with “onion skinning” due to new subperiosteal bone formation.

Question 106

Developmental dysplasia of the hip (DDH)

Answer 106

Risk factors

• Breech positioning
• Positive family history
• Excessively tight swaddling

Clinical features

• Red flags
  
  • Positive Ortolani test
  • Dislocated hip
  • Limited hip abduction
• Supportive findings
  
  • Limb length discrepancy
  • Asymmetric gluteal/inguinal/thigh creases

Management

• Red flags: Refer to orthopedic surgery
• Supportive findings or risk factors
  
  • Age <4 months: Hip ultrasound
  • Age >4 months: Hip radiograph

Developmental dysplasia of the hip (DDH) It is described as a “clicky” or “clunky” hip. There can be a familial component to this in addition to physcial risk factors (such as oligohydramnios and breech presentation). Newborns with risk factors without clinical findings will ultimately receive imaging with ultrasound at 4-6 weeks. You would most likely re-examine the patient at 2 weeks and proceed with ultrasound at 4 if the instability is still present.

Risk factors include breech presentation, female sex, white ethnicity, and family history of DDH. Because many patients have no risk factors, all infants should have serial hip examinations from birth until age 1. The Barlow and Ortolani maneuvers assess joint stability, and a palpable “clunk” should prompt referral to an orthopedic surgeon. These maneuvers may be negative or equivocal, and additional signs, such as leg-length discrepancy (eg, Galeazzi test) or asymmetric inguinal skin folds, can also be indicators of DDH.

Infants with abnormal examination should undergo bilateral hip 🔊 ultrasonography. After age 4 months, when the femoral head and acetabulum are ossified, x-rays are preferred to evaluate acetabular development and positioning. Confirmed DDH is treated with a Pavlik harness, a splint that holds the hip in flexion and abduction while preventing extension and adduction.

Question 107

Genu varum

Answer 107

(bowlegs) is a condition in which the legs angulate away from midline, causing a gap between the knees. This child likely has physiologic genu varum, a normal bowing that appears from birth to age 2 due to expected lower extremity alignment changes. This angulation is often noticeable as the child begins to walk around age 12-15 months.

Characteristics of physiologic genu varum include:

• Symmetric bowing
• Normal stature
• No leg length discrepancy
• No lateral thrust when walking

Diagnosis is clinical. Management is reassurance and observation as physiologic genu varum resolves by age 2.

Question 108

Transient synovitis (TS)

Answer 108

Transient synovitis (TS) is a common, self-limiting, inflammatory hip condition that occurs in children age 3-8. The etiology is unclear but often involves postviral or, less commonly, 💥posttraumatic (eg, gymnastics class) joint inflammation. In some cases, no preceding trigger is identified.

Presentation includes a well-appearing child with acute hip pain or referred knee pain. Knee examination is normal, and patients often hold the hip flexed, abducted, and externally rotated to relieve pressure in the joint space. Limping is common, although patients can usually bear weight on the affected leg. Fever is typically absent (or low-grade), and laboratory evaluation (eg, C-reactive protein, white blood cell count) is usually normal.

Dx: Ultrasound reveals small unilateral or bilateral ♒effusions (even when symptoms are confined to one hip). Treatment of TS is conservative (eg, nonsteroidal anti-inflammatory medications), and symptoms generally resolve within days to weeks.

Question 109

Juvenile idiopathic arthritis

Answer 109

Clinical features

• Symmetric arthritis for at least 6 weeks
  
  • Polyarticular: ≥5 joints involved
  • Oligoarticular: <5 joints involved
  • Systemic: Varying degrees of joint involvement, plus fever & rash

Laboratory findings

• Elevated inflammatory markers (erythrocyte sedimentation rate, C-reactive protein)
• Hyperferritinemia
• Hypergammaglobulinemia
• Thrombocytosis
• Anemia

Juvenile idiopathic arthritis (JIA) is a chronic autoimmune disorder of childhood subdivided into systemic JIA, oligoarticular JIA, and polyarticular JIA.

Oligoarticular JIA affects <5 joints whereas

Oligoarticular JIA, the most common form, is characterized by involvement of ≤4 joints (ie, <5 joints) within the first 6 months of disease onset. Systemic symptoms (eg, fever, rash) do not occur. Cx: Uveitis (ie, intraocular inflammation) is a serious complication that develops in a minority of patients with oligoarticular JIA. Ophthalmologic screening examinations are performed regularly because untreated uveitis is often asymptomatic and can lead to irreversible vision loss. Although not present in all patients with oligoarticular JIA, antinuclear antibodies are a risk factor for uveitis. Additional laboratory findings (eg, leukocyte count, hemoglobin, erythrocyte sedimentation rate) are typically normal in oligoarticular JIA.Treatment is aimed at relieving inflammation and includes nonsteroidal anti-inflammatory drugs, intraarticular glucocorticoids, and disease-modifying antirheumatic drugs.

Polyarticular JIA affects ≥5 joints.

Patients with this subtype develop arthritis in ≥5 joints within 6 months of symptom onset. In addition, diagnosis requires arthritis in at least 1 joint to be present for at least 6 weeks. The most commonly affected joints are the knees, wrists, ankles, and small joints of the hands and feet.

Laboratory findings reflect inflammation, including elevated inflammatory markers (eg, erythrocyte sedimentation rate, C-reactive protein), hyperferritinemia, hypergammaglobulinemia, and thrombocytosis. Anemia, due to chronic inflammation and iron deficiency, is also seen. Treatment depends on the extent of the disease but includes anti-inflammatories (eg, NSAIDs, glucocorticoids) or disease-modifying antirheumatic drugs (DMARDs).

Systemic JIA, the least common subtype, has a varying number of affected joints but classically presents with recurrent fever and rash.

Question 110

Osteomyelitis in children

Answer 110

Pathogenesis

• Hematogenous spread
• Staphylococcus aureus most common cause

Clinical features

• Fever, irritability
• Limited function (eg, limp)
• Bony tenderness, swelling

Diagnosis

• Elevated ESR, CRP, WBC count
• Blood culture
• X-ray (often normal), MRI
• Definitive: Bone biopsy/culture

Treatment

• Antistaphylococcal antibiotic (eg, vancomycin)

Although trauma (eg, surgery, injury) can sometimes introduce infection to bone, in children osteomyelitis is most commonly caused by hematogenous spread. Bacteria (typically Staphylococcus aureus) travel through the bloodstream and seed the well-vascularized metaphysis of long bones (eg, femur), resulting in focal bone marrow infection. Inflammation compromises blood flow, allowing the infection to penetrate the bony cortex and cause necrosis.

Signs of bony inflammation include fever and pain (which may initially be referred to the knee) as well as swelling, erythema, and point tenderness over the affected area. Inflammatory markers are typically elevated and blood culture can help determine the infectious etiology. Radiographs may be normal initially or reveal periosteal elevation (due to subcortical purulence) or cortical thickening. Although inflammation on MRI typically confirms the diagnosis, biopsy and culture of the infected bone is the gold standard for diagnosis. Treatment is with antistaphylococcal antibiotics (eg, vancomycin).

Question 111

Septic arthritis

Answer 111

Pathogenesis

• Age <3 months: Staphylococcus aureus, group B Streptococcus, gram-negative bacilli
• Age ≥3 months: Staphylococcus aureus, group A Streptococcus

Clinical features

• General: fever, fussiness, poor feeding, refusal to bear weight,
• Fever
• Joint:
  
  • Lack of movement
  • Irritability with repositioning (eg, diaper changes)
  • Asymmetric swelling

Laboratory findings

• Elevated WBC, ESR, CRP
• ♒ Effusion on ultrasound

Management

• Joint aspiration
• Antibiotics

Staphylococcus aureus is the most common pathogen, but group B Streptococcus and gram-negative bacilli (eg, Klebsiella pneumoniae, Escherichia coli) also occur frequently in children age <3 months.

Presentation classically includes acute onset of fever, monoarticular joint pain, and inability to bear weight. In infants, symptoms may be nonspecific, including fever, inconsolability, and poor feeding, as in this case. Subtle signs of joint involvement (most commonly knee and hip) in infants include lack of movement of the affected side (“pseudoparalysis”) and excessive fussiness during diaper changes or repositioning (as seen here). Infants often lie with the affected hip flexed, abducted, and externally rotated to maximize joint space and comfort. Physical examination may reveal pain with active or passive motion as well as asymmetric swelling.

Supportive findings include leukocytosis with neutrophilic predominance and elevated inflammatory markers (eg, C-reactive protein, erythrocyte sedimentation rate). Management includes joint aspiration and prompt initiation of antibiotics.

Dx: Arthrocentesis to obtain synovial cultures and confirm the diagnosis. Purulent synovial fluid with >50,000/mm3 leukocytes is consistent with septic arthritis. After blood and synovial cultures are obtained, empiric parenteral antibiotics are administered to target the most likely pathogens (Staphylococcus aureus, streptococci). Antibiotics preceding cultures can interfere with isolation of the offending organism and lead to false-negative results. Due to the risk of permanent joint destruction, prompt surgical drainage will likely be required to decompress the joint space and remove infectious debris.

Question 112

Autoantibodies

Answer 112

Rheumatoid arthritis

• RF: 70-80
• Anti-CCP: 95

Systemic lupus erythematosus

• ANA: 95
• Anti-dsDNA/anti-Sm: 96

Drug-induced lupus

• ANA: 95
• Antihistone: 95

Diffuse systemic sclerosis

• ANA: 95
• Anti–Scl-70 (anti–topoisomerase I): 99

Limited systemic sclerosis

• ANA: 95
• Anticentromere: 97

Polymyositis/dermatomyositis

• ANA: 75
• Anti–Jo-1: 99

Primary Billiary cholangitis

• ​antimitochondrial

Question 113

Ehlers-Danlos syndrome (EDS)

Answer 113

Ehlers-Danlos syndrome (EDS), a collection of genetic disorders marked by impaired synthesis or processing of connective tissue (eg, collagen, extracellular matrix). Although manifestations vary depending on the genetic mutation, most cases are marked by ≥1 of the following:

• Joint hypermobility/laxity, which may result in multiple joint dislocations
• Skin hyperextensibility, which allows skin to stretch ≥4 cm
• Tissue fragility, which leads to easy bruising and spontaneous organ rupture
• Poor wound healing, which leads to the formation of wide, atrophic scars (“cigarette paper–like”)

Confirmation of EDS generally requires referral to a clinical geneticist for genetic testing (eg, COL5A1, COL5A2 mutation).

Question 114

Type II osteogenesis imperfecta

Answer 114

Pathophysiology

• Autosomal dominant
• Type 1 collagen defect

Ultrasound findings

• Multiple fractures
• Short femur
• Hypoplastic thoracic cavity
• Fetal growth restriction
• Intrauterine demise

Prognosis

• Lethal

An intrauterine fetal demise associated with growth restriction, multiple limb fractures, and a hypoplastic thoracic cavity is consistent with type II osteogenesis imperfecta (OI). Type II OI is an autosomal dominant disorder due to defective type 1 collagen synthesis that results in decreased bone density and increased skeletal fragility. This disorder has a varying spectrum of severity, from mild (type I), moderate (types III-IX), to fatal perinatal (type II) disease.

Type II OI is typically diagnosed via antenatal ultrasound findings of multiple fractures, a shortened femur, a hypoplastic thoracic cage, and growth restriction. Type II OI is lethal; most fetuses either die in utero, during delivery due to trauma, or shortly after delivery due to pulmonary hypoplasia (a complication of thoracic cavity hypoplasia). Infants who survive delivery are given supportive care.

Question 115

Rhabdomyolysis

Answer 115

Etiology

• Skeletal muscle lysis/necrosis due to:
  
  • Crush injury or prolonged immobilization
  • Intense muscle activity (eg, seizure, exertion)
  • Drug/medication toxicity (eg, statins)

Clinical features

• Muscle pain and weakness
• Dark urine (myoglobinuria/pigmenturia)
• • blood on urinalysis & no RBCs on microscopy
• ↑ serum K and PO4, ↓ serum Ca, ↑ AST > ALT
• Acute kidney injury

Diagnosis

• Serum creatine kinase >1,000 U/L
• Consistent clinical features

Management

• Aggressive intravenous fluid resuscitation
• Sodium bicarbonate in some cases

Alcohol binges can cause acute alcohol myopathy that predominantly affects the lower extremities, causing pain, weakness, and swelling. It likely occurs via direct toxicity of ethanol and its metabolites, leading to disruption of myocyte membranes. Cocaine abuse further contributes to muscle damage via both vasoconstrictive skeletal muscle ischemia and direct myocyte toxicity.

Up to 50% of patients with rhabdomyolysis will develop acute kidney injury (AKI). During muscle cell lysis, intravascular fluid is shifted into the damaged muscle tissue, and heme-containing myoglobin is released into the bloodstream. The intravascular volume depletion causes an initial prerenal insult, which is followed by a subsequent insult from direct tubular toxicity of heme (pigment nephropathy).