[Hypouricaemia (author's transl)].

Hypouricaemia (blood level blow 2 mg/100 ml or 12 mumol/100 ml) is rarely observed, i.e., in less than 1% of hospitalized patients. Hypouricaemia can be induced by any of three mechanisms: a decrease in uric acid synthesis due to deficient xanthine oxydase (e.g., hereditary xanthinuria, severe liver disease, treatment with allopurinol); increased uricolysis due to drug therapy; increased urinary excretion of uric acid. This increased urinary excretion is due to abnormal uric acid transport in the proximal tubule. It is sometimes observed alone (primary hereditary anomaly of tubular uric acid transport, severe liver disease or neoplasia, drugs, or contrast media). It can also be observed in association with other proximal tubular anomalies, constituting a Fanconi syndrom. Among observations of hypouricaemia, 50% result from drug therapy and approximately 30% are secondary to liver diseases or neoplasia. It has no special clinical consequence. Nevertheless, the observation of hypouricaemia in a patient should indicate the possibility of drug intoxication or an underlying disease, in particular neoplasia. Measurement of uric acid clearance is a simple method of determining the mechanism responsible and of guiding diagnosis.