Hyperurichemie

Hyperurichemie, also known as hyperuricémie in French and hyperuricemia in English, refers to an elevated concentration of uric acid in the blood. It is defined by serum urate levels above the normal range, with common thresholds around 6 mg/dL (360 µmol/L) for women and 7 mg/dL (420 µmol/L) for men, though exact cutoffs may vary by laboratory.

The condition arises from a combination of increased production of uric acid and/or reduced excretion by the kidneys. Overproduction can occur with high purine intake, rapid cell turnover, or certain metabolic conditions, while underexcretion is often related to impaired renal function, dehydration, or medications that reduce urate clearance. Lifestyle factors such as obesity, metabolic syndrome, diabetes, alcohol use (especially beer), and high-fructose diets can contribute. Genetic factors affecting urate transport in the kidneys also play a role.

Most people with hyperuricemia are asymptomatic. When urate crystals accumulate in joints, tendons, and soft tissues, gout can develop, presenting as sudden severe joint pain, redness, and swelling, commonly in the big toe. Urate crystals can also form kidney stones or contribute to chronic kidney disease and tophaceous gout with visible deposits under the skin.

Diagnosis relies on serum urate measurement, repeated if necessary, and assessment for crystal deposition in synovial fluid or on imaging. Management focuses on reducing uric acid to target levels, typically below 6 mg/dL (360 µmol/L), through lifestyle changes and urate-lowering therapy such as xanthine oxidase inhibitors (eg, allopurinol, febuxostat) or, in select cases, uricosurics or biologic agents. Initiation of therapy may include prophylaxis to prevent flares during dose escalation.