MusculoskeletalPending review

Gout

A crystal arthritis in which chronically raised urate exceeds its solubility, deposits as monosodium urate crystals in cool peripheral joints and triggers explosive innate inflammation, treated acutely by damping inflammation and long-term by lowering urate.

First principles

Gout is a solubility problem before it is an inflammation problem

Urate is the end-product of purine breakdown in humans, who lack the enzyme uricase that other mammals use to degrade it further. Above roughly 400 micromol/L urate exceeds its solubility in body fluids and begins to precipitate as monosodium urate crystals. So the root cause of gout is a sustained excess of urate: from under-excretion (the majority, worsened by renal impairment, diuretics and alcohol) or over-production. No hyperuricaemia, no crystals; this is why the long-term cure is lowering urate, not treating pain.

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Educational content pending clinical review. Not medical advice.