Crystal Arthropathies Flashcards
What is urate formed from?
Urate is the final product in purine breakdown
What is gout?
Crystal arthropathy caused by deposition of urate crystals in a joint
What are risk factors for developing gout?
Male
Obesity
High alcohol intake
High dietary seafood/red meat
Diuretics
Hyperuricaemia (renal failure/dehydration)
How does gout present?
Intensely painful, red and swollen joint
What is the most common joint affected by gout?
1st metatarsophalangeal joint
What is the most important condition to rule out in suspected gout and how is this done?
Septic arthritis
Synovial fluid sample
What is the diagnostic test for gout and what does it show?
Synovial fluid analysis
Shows needle shaped, negatively birefringent crystals
Urate can be normal in gout. True or false?
True
Normal in 25% cases
How is acute gout managed?
NSAIDs
Colchicine (for those who can’t tolerate NSAIDs)
What is a common side effect of colchicine?
Diarrhoea
What class of drugs are used prophylactically to prevent gout and how do they work?
Name 2.
Which is first line and what are the reasons for using the other?
Xanthine oxidase inhibitors
Block urate production, preventing hyperuricaemia
Allopurinol
Febuxostat
Allopurinol is first line
Febuxostat is used if patient
- develops vasculitic rash from allopurinol
- is on axithioprine
- has renal impairment
What is pseudogout?
Crystal arthropathy caused by deposition of calcium pyrophosphate in a joint
What is seen on synovial fluid sample in pseudogout?
Rhomboid, positively birefringent cystals
What prophylactic treatments are there for pseudogout?
None
What is chondrocalcinosis?
Deposition of calcium pyrophopshate crystals in cartilage and soft tissues without acute inflammation
