Musculoskeletal Pain Flashcards
What is the next diagnostic step for joint paint (monoarticular) that is not preceded by a history of joint pain, sudden onset, and non traumatic, but is edematous, erythematous, and warm?
- Joint aspiration for examination of joint fluid to identify crystals and exclude infection
What is the treatment of acute gout?
- NSAID
- Colchicine
- Glucocorticoids
Why must an infected joint be ruled out quickly (i.e. 24hrs?)
Exclusion of infectious etiology is paramount because cartilage can be destroyed within the first 24hrs of infection
What age groups are most affected by gout?
- Men => 30-50
- Women => 50-70
List some exacerbating factors of gout.
- Alcohol consumption
- Trauma
- Surgery
- Large meals (often protein) or thiazides that induce hyperuricemia
What type of crystals are seen in crystal induced arthritis?
- Upon microscopy, monosodium urate (MSU) crystals (look like needles) are seen; these have a strong negative birefringence.
Describe the appearance of calcium pyrophosphate dehydrate crystals under microscopy.
Calcium pyrophosphate dehydrate => rod shaped, rhomboid, weakly positive birefringence
Describe the appearance of calcium hydroxyapatite crystals under microscopy.
Calcium hydroxyapatite => cytoplasmic inclusions that are NOT birefringent
Describe the appearance of calcium oxalate crystals under microscopy.
Calcium oxalate => bipyramidal appearance, strongly positive birefringence; seen mostly in end stage renal disease patients
How does the CBC of a crystal induced arthritis differ from a septic joint?
- Crystal induced arthritis => white cells 2,000-60,000
- Septic joint => ~100,000 white cells and >90% PMNs
What is the difference between gout and pseudo gout?
- Gout => due to uric acid deposition in the joints
- Pseudogout => due to calcium pyrophosphate dehydrate crystals (rhomboid, weakly positive birefringent)
What is the DDX for non traumatic swollen joint/joint pain?
- Gout/Pseudogout
- Infectious arthritis
- Osteoarthritis
- Rheumatoid arthritis
What is the pattern of articular involvement in bacterial arthritis?
Monoarticular => often knee, hip, shoulder
What organisms may be responsible for chronic monoarticular pain?
- Mycobacterium
- Fungi
Acute, polyarticular arthritis may be due to what kinds of infections?
- Endocarditis
- Disseminated gonococcal infection
Patients with rheumatoid arthritis are susceptible to joint infections from which organisms?
- Staph. aureus
Patients with HIV are susceptible to joint infections from which organisms?
- Pneumococcal, salmonella, H. influenzae
Patients who are IV drug users are susceptible to joint infections from which organisms?
- Streptococcal, staphylococcal, gram negative, or psuedomonas
How does a septic joint differ from cellulitis, bursitis, or osteomyelitis?
- Septic joints have very limited ROM in comparison to cellulitis, bursitis, or osteomyelitis
What are the main features of osteoarthritis?
- > 65yo
- Associated with trauma, history of repetitive joint use, and obesity (especially knee)
- Primarily affects cartilage, but can damage bone surface, synovium, meniscus, and ligaments
- Dull, deep, and achey pain
- Worse with activity
- Crepitus with passive ROM
- X rays may reveal => bone sclerosis, subchondral cysts and osteophytes
What are the main features of rheumatoid arthritis?
- Onset at 30-55yo
- Women more than men
- Morning stiffness
- Involvement of 3+ joints
- Symmetric arthritis
- Positive rheumatoid factor, ESR, CRP, anemia, thrombocytosis, or low albumin
- Rheumatoid nodules
- Xray => decalicifications or erosions
What is the maintenance therapy for gout?
- Probenecid => increases urinary excretion of uric acid
- Allopurinol => reduces the production of uric acid
What is the therapy for a septic joint?
- A septic joint requires surgical debridement/ drainage and antibiotics
What is the therapy for DJD?
- Mobility exercises
- Weight loss
- Intra-articular corticosteroid injections every 4-6mo
- Joint replacement in severe disease
What is the therapy for rheumatoid arthritis?
- Exercises to protect mobility and muscle strength (PT and OT)
- NSAIDs
- Glucocorticoids
- DMARDS (disease modifying anti-rheumatic drugs) => Sulfasalazine and methotrexate
- Anticytokines => infliximab and etanercept
- Topical analgesics
What should be monitored especially when administrating rheumatoid medications?
- Monitor liver function
What action is the most common cause of ankle sprains?
- Ankle sprains are the results of inversion of an ankle that is plantar flexed
Which structures protect the medial ankle from injury?
- Tibulotalar joint and the deltoid ligament protect the medial ankle from injury
What is the most commonly injured ligament of the lateral ankle?
- Anterior talofibular ligament (followed by the calcaneofibular ligament)
When should ankle X-rays be performed?
- If there is bony tenderness over the posterior edge or tip of the distal 6cm of either the medial or lateral malleolus
- If the patient is unable to bear weight immediately or when examined
When should foot X-rays be performed?
- If there is bony tenderness over the navicular bone, the base of the fifth metatarsal or if the patient is unable to bear weight
What is the management of ankle sprains?
- Protection (splinting or casting)
- Rest
- Ice
- Compression
- Elevation
- Acetaminophen or NSAIDs can be used for pain relief
What is the difference between a sprain and a strain?
- Sprain => a stretching a tearing injury of a ligament
- Strain => stretching or tearing injury of a muscle or tendon
In a possible rotator cuff injury or tear, how would we test supraspinatus?
- Empty can test=> with arm abducted, elbow extend and thumb pointing down, patient elevates arm against resistance
In a possible rotator cuff injury or tear, how would we test infraspinatus and teres minor?
- External rotation => with elbows at sides and flexed at 90, patient externally rotates against resistance
In a possible rotator cuff injury or tear, how would we test subscapularis?
- Lift off test => patient places dorsum of hand on lumbar back and attempts to lift hand of of back
In a possible rotator cuff injury or tear, how would we test subacromial impingement?
- Hawkin’s impingement => pain with internal rotation when the arm is flexed to 90 degrees with the elbow bent to 90 degrees
How would we test for a large rotator cuff tear?
- Drop arm rotator cuff => patient is unable to lower his arm slowly form a raised position
How would we test for an anterior talofibular ligament tear?
- Anterior drawer => examiner pulls forward on patient’s heel while stabilizing lower leg with other hand
- Excessive translation of joint suggests ATFL tear
How would we test for a calcaneofibular ligament tear?
- Inversion stress test => examiner inverts ankle with one hand while stabilizing lower leg with other hand
- Excessive translation or palpable “clunk” of talus on tibia suggests ligament tear
What is syndesmosis?
A syndesmosis is a slightly movable fibrous joint in which bones such as the tibia and fibula are joined together by connective tissue.
How would we test for syndesmosis?
- Squeeze test => examiner compresses tibia/fibula at midcalf
- Pain at anterior ankle joint would be positive for syndesmosis
How would we test for ACL injury/tear?
- Lachman test => knee in 20 flexion, examiner pulls forward on upper tibia while stabilizing upper leg
- ACL tear => excessive translation with no solid end point suggests tear
How would we test for MCL tear?
- Valgus stress => in full extension and at 30 degree flexion, medial directed force on knee with lateral directed force on ankle
- Excessive translation suggests tear
How would we test for a lateral collateral ligament tear?
- Varus stress=> in full extension and at 30 degree flexion, lateral directed force on knee and medial directed force on ankle
- Excessive translation suggests tear
When should a knee X-ray be performed?
- patient is >55yo
- isolated patella tenderness
- tenderness of the head of the fibula
- inability to flex the knee to 90 degrees
- inability to bear weight for 4 steps immediately and in the exam room
