Osteoarthritis and crystal arthropathies Flashcards
What is osteoarthritis?
Progressive degenerative condition affecting the joints. Gradual thinning of cartilage, loss of joint space and formation of bony spurs (osteophytes)
Cartilage consists predominantly of what collagen?
Type II - linked by covalent bonds
What happens to the joint during disease?
Loss of matrix, release of cytokines (IL1, TNF) and prostaglandins
What is the term used to describe grinding or creaking on movement?
Crepitus
What are the symptoms of osteoarthitis?
Stiffness, bony swellings, joint deformity, effusions, soft tissue swelling
What are the bony enlargements seen at DIPs called?
Heberdens nodes
What are the bony enlargements seen at PIPs called?
Bouchards nodes
Genu varus is?
Bowing of the legs
Genu valgus is?
Knock knee
What are the risk factors for OA?
Age, Gender (more women), Genetic, occupation, previous injury, obesity
What are the typical OA changes seen on XR?
Joint space narrowing
Subchondral sclerosis
Bony cysts
Osteophytes
What joints does rheumatoid arthritis affect?
Metacarpophalangeal and proximal interphalangeal
What joints does osteoarthritis affect?
Distal interphalangeal
Carpometacarpal
What pharmacological managements are there for arthritis?
Analgesia - paracetamol, compound analgesics, topical analgesia
NSAIDs
Pain modulators - tricyclics (amitriptyline)
Anti convulsants (gabapentin)
Steroid joint injection
What are the two main crystal arthropathies?
Gout (monosodium urate)
Pseudogout (calcium pyrophosphate dihydrate)
What is gout
Inflammatory arthritis associated with monosodium rate crystal deposition
What is gout caused by?
Overproduction (genetic - leech nyhan, Von Gierke - high cell turnover, overconsumption of foods rich in purines) or under excretion of uric acid (renal insufficiency, starvation, dehydration, hypothyroidism, hyperparathyroidism, drugs (diuretics, levodopa, cyclosporin A) alcohol abuse)
When is the best time to measure serum urate?
2 weeks following an acute attack
Describe acute monoarticular gout
Rapid onset, red hot joint, severe pain
What are the differentials for gout?
Septic arthritis
Trauma
Seronegative arthritis (eg psoriatic arthritis)
What are the investigations for gout?
CRP, PV/ESR, WCC, XR - normal in acute attacks
What would be found on joint aspirate?
Needle shaped crystals, negative birefringence on polarised light
What are forms of urate lowering therapy?
Allopurinol/ Febuxostat
Aim for target serum rate <0.3 mmol/l
What does pseudo gout affect?
Fibrocartilage
