- transient attacks of acute arthritis initiated by crystallization of monosodium urate with and around joints

- 90% primary - 10% secondary: increased nucleuc acid turnover (leukemia), chronic renal disease, congenital (Lesch-Nyhan syndrome, HGPRT deficiency)

- inflammation is triggered by the precipitation of MSU crystals into the joints, which result in the production of cytokines that recruit leukocytes

- low temperatures favor precipitation

Clinical course- more common in men, patients with obesity, metabolic syndrom, excess alcohol intake, renal failure- 50% occur in the first metatarsophalangeal joint