urihappoa

Urihappo (uric acid) is a weak organic acid and a natural product of purine metabolism. Its chemical formula is C5H4N4O3, and at physiological pH it largely exists as the urate anion. In humans, uric acid is produced during the breakdown of purines from nucleic acids and dietary sources and is primarily eliminated by the kidneys, with some excretion via the gut. It is relatively poorly soluble in water, especially at lower temperatures, which can lead to crystallization under certain conditions.

Biological role and metabolism

Uric acid is the end product of purine catabolism in humans and higher primates. The body handles uric acid through a balance of production and excretion; disruption of this balance can raise serum uric acid levels (hyperuricemia). Uric acid can form crystals when concentrations exceed solubility limits, which may precipitate in tissues or urine.

Clinical significance

Elevated uric acid levels are associated with gout, a form of inflammatoryarthritis characterized by needle-shaped monosodium urate crystals in joints and periarticular tissues. Uric acid crystals can also accumulate in the kidneys, contributing to uric acid stones. Hyperuricemia is linked with metabolic syndrome, obesity, renal impairment, and certain medications.

Diagnosis and management

Diagnosis typically involves measuring serum uric acid levels and assessing uric acid excretion in urine, along with clinical evaluation. Joint aspiration showing negatively birefringent, needle-shaped monosodium urate crystals supports gout. Management includes dietary changes to reduce purine intake, increased hydration, and pharmacological urate-lowering therapies (for example, allopurinol or febuxostat) and sometimes uricosuric agents, depending on the underlying condition.