MSK Flashcards
What joints are primarily affected by osteoarthritis?
Knee
Hip
What distinguishes between rheumatoid and osteoarthritis?
Rheumatoid - pain/stiffness relieved by exercise, exacerbated by lack of movement
Osteoarthritis - pain exacerbated by exercise, relieved by rest
What finger changes are seen in osteoarthritis?
Heberden’s nodes - DIP
Bouchard’s nodes - PIP
What changes are seen on an X-ray in osteoarthritis?
LOSS
Loss of joint space
Osteophytes
Subchondral cysts
Subarticular sclerosis
What would be noted on passive movement of the joint in osteoarthritis?
Decreased range of movement
Pain on movement
Crepitus
What is the treatment for osteoarthritis?
General
• Weight loss
• Physiotherapy
• Topical and heat therapy
Pharmacology
• NSAIDs + PPI
• Intraarticular steroid injections
Surgical - Joint replacement
Where does gout usually first present and why?
Big toe (1st MTP joint) - 70%
Presents in extremities as they are cooler so allows for precipitation of the crystals
Who is typically affected?
Obese, non-white males who drink a lot and eat a lot of meat
It almost never affects pre-menopausal women
Aside from metabolic syndrome, what are some other modifiable risk factors for gout?
Drugs
- Thiazide diuretics
- ACE inhibitors
- Aspirin
Increased cell level/turnover
- Malignancy
- Psoriasis
- Chemotherapy
What investigation do you do for gout?
- Gout is usually a clinical diagnosis
- Joint aspiration with polarised light microscopy - this would show negatively birefringent needle shaped crystals
- If they are systemically unwell, you need to send the joint aspiration for MC&S to rule out septic arthritis
What is seen on an X-ray of chronic gout?
Punched out lesions (rat-bites)
Areas of sclerosis
Tophi
What is the onset of pain in gout? Compare this onset to that of septic arthritis
Quick onset - 3-12 hours
Septic arthritis is even more acute onset - 1-2 hours
What is the acute management for gout?
NSAIDs = 1st line
Colchicine = 2nd line
Intra-articular steroids = 3rd line
IM steroids - if it is widespread (e.g. midfoot, ankle, 1st MTP)
What is the main side effect of colchicine?
v v bad diarrhoea - stop if they get this
What drug is given for prophylaxis of gout? What class is it? When should it not be given?
Allopurinol = xanthine-oxidase inhibitor
Do not give in acute attack of gout
What is uric acid the end product of?
The breakdown of purines (adenine + guanine)
How is urate excreted by the body?
2/3rd by kidneys
1/3rd by GI tract
What joint is most commonly affected by septic arthritis?
Knee
What organisms can cause septic arthritis
- Coagulase negative staphylococci - most common in prosthetic joints
- Staph aureus - most common in children > 2 years
- Streptococci
- Neisseria gonorrhoea - most common in sexually active young people
- Haemophilus influenzae - used to be the most common cause in children but less common now due to vaccination
- E. Coli
What is the classic presentation of septic arthritis?
Classic triad of:
- Fever
- Joint pain
- Reduced range of movement
What bloods would you need to do in suspected septic arthritis?
FBC - high WCC
CRP - monitors disease progression
Blood cultures
How do you treat septic arthritis?
Analgesia
Antibiotics
- 2g IV flucloxacillin QDS for 2 weeks then 1g PO flucloxacillin QDS for 4 weeks
- Clindamycin if penicillin allergic
- If MRSA suspected - vancomycin
- If gonococcal/E. Coli - cefotaxime
Surgical
- Wash out the joint/surgical drainage if it is a deep joint e.g. hip
- If contraindications to surgery, can do daily aspirations for symptom relief
What is rheumatoid arthritis?
A chronic inflammatory autoimmune disease affecting synovial joints, leading to joint and periarticular destruction
What joints are typically affected by RA? Is it symmetrical?
Symmetrical polyarthritis
Mostly affects small joints of the hands
What hand signs are seen in RA?
• Z thumb
• Swan neck deformity = fixed flexion of MCP and DIP, hyperextension of PIP
• Boutonniere’s = extension of MCP and DIP joint, flexion of PIP
• Ulnar deviation
- Hand muscle wasting
What are the key rheumatoid complaints across the body?
PRISMS
Pain - polyarthritis
Rashes + skin lesions - ulcers, rashes, nail fold infarcts
Immune - Sjorgen’s = dry eyes, dry mouth, chronic cough
Stiffness - worse in morning
Malignancy
Swelling + sweats - especially in the morning
What extra-articular manifestations of rheumatoid arthritis might you see?
Rheumatoid nodules on forearms, in eyes, in heart and lungs
What cardiac diseases can be caused by rheumatoid arthritis?
- Ischaemic heart disease
- Pericarditis
- Pericardial effusion
What specific blood tests can you do for rheumatoid arthritis?
Explain which is more specific/sensitive for RA and which you would do first/second.
Rheumatoid factor (RF) - found in 70% of rheumatoid patients and 1% of general population
- More sensitive for RA
- High levels are associated with RA but it is a poor marker for monitoring disease (instead use inflammatory markers for disease monitoring)
Anti-CCP antibodies - found in 98%
- More specific than RF
- It is sent off second-line if RF comes back negative in a patient in whom you suspect disease
Name some DMARDs used in Rheumatoid Arthritis.
Which are used for mild or severe disease?
- Methotrexate - used in more severe disease
- Sulfasalazine - used in milder disease
- Azathioprine
- Hydroxychloroquine
It is important to commence DMARDs as early as possible after symptoms occur (ideally within 3 months)
What is a contra-indication of sulfasalazine?
Aspirin hypersensitivity because it is an aminosalicylate
What are some side effects of methotrexate?
- Pneumonitis
- Anaemia (inhibits folate production)
- Mouth ulcers
What is reactive arthritis?
An autoimmune response to infection elsewhere in the body causing arthritis
Usually it is a male, who is HLA-B27 positive and had an STI or GI infection
What is the classic triad of reactive arthritis and when do the symptoms usually start?
Urethritis
Conjunctivitis
Arthritis
Can’t see, can’t pee, can’t climb a tree!
Symptoms occur 4 weeks post-infection
What skin changes might you see in reactive arthritis?
- Erythema nodosum
- Keratoderma blenorrhagica = psoriasis-like lesions on soles of feet/palms of hands
What tests are done in reactive arthritis?
ESR/CRP - raised
Stool MC&S - GI infection
Urethral/cervical swabs - screen for STIs
What allele is associated with ankylosing spondylitis?
HLA B27
What are the outer and inner parts of vertebrae called?
Annulus fibrosus = peripheral fibrocartilaginous part
Nucleus pulposus = central gelatinous part
What part of the spine is most prone to disc lesions?
Lumbar spine
L5 to S1 is most common site for disc herniation
L4 to L5 is second most common site
What commonly causes cervical disc lesions?
Whiplash injury
How can herniation of a lumbrosacral disc present?
Sciatica - the leg pain is more severe than the back pain
Greater pain on raising the leg
Cauda equina syndrome = neurosurgical emergency
What are the symptoms of cauda equina syndrome?
Back pain Radicular pain down legs Asymmetrical weakness and loss of sensation in the legs Saddle anaesthesia Urinary retention Faecal incontinence Erectile dysfunction
What drugs can be given for nerve pains?
Tricyclic antidepressants e.g. amitriptyline
Gabapentin
What surgical procedure is done in acute cord compression?
Laminectomy = removes the back of a vertebra to relieve pressure on nerves (surgical decomperssion)
What are the risk factors for osteoporosis?
SHATTERED
Steroid use/Cushing's syndrome Hyperthyroidism/hyperparathyroidism Alcohol Thin low Testosterone Early menopause - oestrogen stimulates osteoblasts and inhibits osteoclasts Renal/liver failure Erosive or inflammatory bone disease Dietary low calcium/malabsorption
Describe the pathogenesis of osteoporosis
It is the end result of an imbalance between osteoclasts and osteoblasts
During ageing, bone breakdown by osteoclasts overtakes bone formation by osteoblasts
This results in reduced bone mineral density and changes in bone composition/architecture
How does osteoporosis usually present?
A fragility fracture
Where do fragility fractures most commonly occur?
Vertebrae
Proximal femur
Distal radius (Colles fracture)
What is the main investigation for osteoporosis and what values indicate what?
DEXA scan - calculates bone mineral density in g/cm2
Normal: > -1
Osteopenia: -2.5 < T < -1
Osteoporosis: < -2.5
What is the main drug treatment for osteoporosis?What is its mechanism?
Bisphosphonates e.g. alendronic acid
They inhibit resorption of bone by osteoclasts. This happens because they have similar structure to pyrophosphate (natural product of bone breakdown) so they are readily incorporated into the bone. The bisphosphonates accumulate in osteoclasts and promote apoptosis.
What are some other indications for bisphosphonates?
Bone metastases
Paget’s disease
Severe hypercalcaemia of malignancy
What are some side effects of bisphosphonates?
Oesophagitis - prevent by taking the tablet with water and sitting upright for 30 mins after
Jaw osteonecrosis - prevent with good dental hygiene and no smoking
Femoral fracture
What supplements should be given in osteoporosis?
Calcium and vitamin D = AdCal
What causes a hemiplegic gait and what does it look like?
Stroke
Unilateral weakness
Circumduction of leg = dragging of affected leg in semicircle
Foot drop
What is a Trendelenburg gait?
Drop of pelvis when lifting the leg opposite to the weak gluteus medius.
Usually due to muscular dystrophy.