Path 7 Flashcards
What crystals are seen in gout and pseudogout and how are they under polarised light?
Gout: needle shaped (MSU - monosodium urate crystals) negative birefringence
Pseudogout: rhomboid shaped calcium pyrophosphate crystals) positive birefringence
rat bite erosions on x-ray
gout
What do you see on x-ray in gout?
rat bite erosions
What do you see on xray in pseudogout?
white lines of chondrocalcinosis
white lines of chondrocalcinosis on xray - diagnosis?
pseudogout
What is the management of gout acutely and long term?>
acute: colchicine, NSAIDs
long term: allopurinol
What group of conditions do gout and pseudogout belong to?
inflammatory crystal arthropathy
What groups of people are affected by gout and pseudogout?
gout: obese, middle aged men
pseudogout: >50yo women
What monoclonal antibody can be used in the management of gout?
IL-1 blockade
do not prescribe routinely, are prescribed by rheumatologists
can be used to treat acute gout flares in patients if NSAIDs and colchicine are contraindicted, not tolerated or ineffective.
management of gout - acute flare and long term
acute: colchicine and NSAID (+ice pack cooling, +/- PPI)
intramuscular or intraarticular steroid injectoins can also be considered. IL-1 blockade can also be considered.
chronic: allopurinol (urate lowering therapy, XO inhibitor); probenecid is second line (inhibits uric acid reabsorption along the renal tubules)
conservative measures: decrease alcohol intake and purine intake (e.g. in sardines, liver, port wine); weight loss if overweight. sufficient fluid intake is recommended.
review medications in case something is causing it.
MoA of probenecid
inhibits uric acid reabsorption along the renal tubules and therefore decreases uric acid levels and can be used as urate lowering therapy in the long term management of gout
increases fractional excretion of uric acid
Why should you administer anti-inflammatory prophylaxis before initiating ULT (urate lowering therapy?
because ULT may trigger, prolong or worsen an acute flare. this is because it causes preexisting urate crystal deposits to dissolve and become mobile
MoA of colchicine
inhibits polymerization of tubulin to reduce motility of neutrophils
types of presentation in gout
acute monoarthritis
chronic tophaceous gout (polyarticular arthritis, tophi deposits behind ear lobes, fingers and elbows, urate kidney stones)
Aetiology of gout
hyperuricaemia due to
- increased intake (e.g. alcohol)
- increased production (e.g. TLS, inherited metabolic abnormalities)
- decreased excretion (e.g. diuretics)