24 - Gout Flashcards
gout AKA?
monosodium urate
define tophi?
accumulation of uric acid in tissues
what mechanism underpins gout?
purine metabolism - having excess uric acid
where does 2/3 of urate come from?
breakdown of purine (result of breakdown of DNA)
where does 1/3 of urate come from?
purine breakdowns of food and drink
where is uric acid excreted?
kidney (70%) and biliary tract (30%)
2 causes of hyperuricaemia?
overproduction and under-excretion
give 4 examples of overproduction leading to hyperuricaemia?
tumour lysis syndrome, severe exfoliative psoriasis, cytotoxic drugs, HGPRT deficiency
give 4 examples of under excretion leading to hyperuricaemia?
renal impairment, hypertension, hypothyroidism, lead poisoning
why does alcohol increase risk of gout? (2)
1 - metabolism of ethanol to acetyl CoA results in increased formation of adenosine monophosphate
2 - inhibits uric acid secretion by increasing lactic acid levels in blood
what causes Lesch Nyan syndrome?
HGPRT deficiency
what is the role of HGPRT enzyme?
recycle purines into purine nucleotide pool
name 2 purines?
hypoxanthine and guanine
describe the pathway of HGPRT deficiency in becoming gout?
purines are not recycled -> purines are broken down and excreted as uric acid -> body produces more purines -> again not recycled -> continues to overproduce uric acid
who gets gout?
usually men, peak age being 70/80s
name 3 RFs associated with gout?
obesity, high fat/seafood diet, dehydration
what is often the classic presentation of flare of gout?
Away on holiday, more alcohol, sunny (dehydration) , aware of sore red big toe at night and in morning it is agony, with difficulty walking and can’t bear to touch it
how long does episode of gout last?
5-7 days
what is the gold standard investigation for gout?
aspiration of joint
name 2 other investigations?
polarising microscopy and culture
symptoms of gout?
severe pain, hot and tender joint, red & shiny skin over affected joints
what is the 1st line management for acute flare of gout?
NSAIDs
when can colchicine be used to treat gout?
use as 1st line if NSAIDs are not appropriate
name 2 groups of people who might not be suited to using colchicine?
elderly and renal impairment
