Calculi

Calculi is the plural of calculus and can refer to two broad domains: solid concretions within the body and formal systems used in mathematics, logic, and computer science. In medical contexts, calculi (stones) are mineralized concretions that form within ducts or cavities and may be asymptomatic or cause obstruction and pain.

The most common calculi are kidney stones (nephroliths) and gallstones (biliary calculi). Stones are typically composed of calcium salts such as calcium oxalate or calcium phosphate, uric acid, struvite, or cystine. Predisposing factors include dehydration, metabolic abnormalities, certain infections, obesity, diet, and immobility. Symptoms range from intermittent flank or abdominal pain to severe colicky pain, depending on obstruction, and may include blood in urine, nausea, or fever. Diagnosis relies on imaging—noncontrast computed tomography, ultrasound, or radiographs—alongside blood and urine tests. Treatment aims to relieve pain, promote passage of small stones, or remove larger ones. Options include hydration and analgesia, medical expulsive therapy, extracorporeal shock wave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. Prevention emphasizes hydration and management of metabolic factors to reduce recurrence, such as controlling calcium, oxalate, uric acid, and citrate levels and addressing underlying conditions.

In mathematics and related fields, calculus refers to a foundational formal system for analysis, and calculi is used when naming multiple such systems, for example the lambda calculus, pi-calculus, or calculi of variations and proofs. The term calculus derives from Latin for pebble or stone, historically linked to counting and calculation.