Crystal Arthropathies Flashcards
what is gout
inflammation in the joint triggered by uric acid crystals
what is the value that indicates hyperuricemia in gout
>0.42mmol/l
what is the prevalence of gout
1.4 in UK, 3.9 in US 7% in men over 65 and 3% in women over 85 male > female
what is affected during acute gout
monoarthropathy = 1st MTP > ankle > knee usually an abrupt onset over night
how long does acute gout take to settle
10 days without treatment 3 days with treatment
what is uric acid levels during attack of gout
it may be normal
what is chronic gout usually associated with
diuretics
what is uric acid levels in chronic gout
high it is the deposit of uric crystals in people with long standing hyperuricaemia
what happens during chronic gout
they may get acute attacks
what is the cause of gout
either increased urate production or reduced urate excretion
what is the more common cause of gout
reduced urate excretion
what causes increased urate production
inherited enzyme defects (HGPRT) myeloproliferative / lymphoproliferative disorders psoriasis haemolytic disorders alcohol (beer, spirits) high dietary purine intake (red meat, seafood, corn syrup)
what causes reduced urate excretion
chronic renal impairment volume depletion eg heart failure hypothyroidism diuretics cytotoxics eg cyclosporine
how is gout diagnosed
raised inflammatory markers serum uric acid raised synovial fluid biopsy renal impairment (may be cause or effect) Xrays
what is seen in synovial fluid biopsy in gout
polarising microscopy shows needle shaped negatively befringement crystals
how is acute attack of gout treated
NSAIDs colchicine IA steroids (often in people unable to take above)
what is colchicine and how does it work
decreases swelling and lessening the build up of uric acid crystals that cause pain in the affected joint
what is given prophylactically in gout
allopurinol febexostat start 2-4 weeks after acute attack require cover with NSAIDs etc
what is allopruinol
purine analog; it is a structural isomer of hypoxanthine (a naturally occurring purine in the body) and is an inhibitor of the enzyme xanthine oxidase therefore, decreases uric acid formation
what is febexostat
also inhibits xanthine oxidase and therefore reduces uric acid formation
what is difference between pseudogout and gout
both are caused by large crystal deposits in joint but it is different crystals
who is pseudogout common in
elderly
what does pseudogout effect
fibrocartilage - knees, wrist, ankles
what are the two types of crystals in pseudogout
calcium pyrophosphate crystals calcium hydroxyapatite crystals
what are the associated conditions in pseudogout
hyperparathyroidism familial hypocalciuric hypercalcaemia haemochromatosis haemosiderosis hypophosphatasia hypomagnesia hypothyroidism gout neuropathic joints ageing amyloidosis trauma
how is pseudogout diagnosed
histology of calcium pyrophosphate crystals and marked rise in inflammatory markers
what does calcium pyrophosphate crystals in pseudogout look like histologically
envelope shaped mildly positive birefringent (refractive index)
how is pseudogout treated
NSAIDs Colchicine Steroids Rehydration
what is hydroxyapatite
hydroxyapatite crystal deposition in or around the joint
what does this crystal deposition in hydroxyapatite lead to
release of collagenases, serine proteinases and IL-1 acute and rapid deterioration
who does hydroxyapatite affect
females, 50-60 years
what is symptom of hydroxyapatite
Milwaukee shoulder
what does this symptom of hydroxyapatite entail
limited range of motion joint pain and inflammation synovial haemorrhagic effusion
how is hydroxyapatite treated
NSAIDs IA steroid injection physiotherapy partial or total arthroplasty
