Lowering of the pH lessens the solubility and increases the likelihood of crystal formation. Causes of hyperuricaemia Diuritec drugs are the main cause of hyperuricaemia. Genetic and environmental factors lead to hyperuricaemia by dreasing the excretion, or increasing the production, of uric acid. In most patients, although there is often a family history, no definite cause can be found. Gout and hyperuricaemia are often associated with obesity, type IV hyperlipoproteinaemia, impaired glucose tolerance, hypertension and ischaemic heart disease.
Pathology Prolonged hyperuricaemia leads to the formation of small crystal aggregates.
These accumulate in the synovium and at external sites, such as the eari, cartilage and olecranon, and may eventually become visible tophi. Crystal deposition may proceed over several years without symptoms. Uric acid and urate deposition in the kidneys can lead to renal stones. Joint inflammation is the result of uptake of crystals by polymorphonuclear leucocytes. Clinical features Classical gout is easily diagnosed.