Uric Acid Metabolism

Question 1

how is allatoin made

Answer 1

purines (genetic markers) -> xanthine -> urate -> allantoin

Question 2

what is a complete def of HGPRT (central enzyme involved in purine metab) called

Answer 2

lesch nyhan syndrome

Question 3

how will HGPRT def/lesch nyhan syndrome present

Answer 3

normal at birth, developmental delay, retardation
hyperuricaemia and choreiform movements
85% self harm

Question 4

how are purines synthesised

Answer 4

de novo in bone marrow is not efficient

salvage and recycling dominates

Question 5

what causes gout

Answer 5

a build up of MSU crystals

Question 6

what is podogra

Answer 6

acute gout

Question 7

how will acute gout (podogra) present

Answer 7

red, hot joint, rapid build up of pain

Question 8

what is the diagnostic investigation for gout and what is an important DDx

Answer 8

tap effusion and view under polarised light with red filter

DDX = pseudogout

Question 9

how will gout look under a red filter

Answer 9

needle shaped crystals, -ve bifridgement, angles L->R

Question 10

how will pseudogout look under a filter

Answer 10

rhombus shaped crystals
+Ve bifridgement
angled R-> left

Question 11

how is gout managed

Answer 11

dec inflam - NSAIDs, colchicine, glucocorticoids

manage hyperuricaemia - rehydrate, allopurinol, probenecid

Question 12

what is important to consider with allopurinol

Answer 12

never give with azathioprine