nefrolithiasis

Nephrolithiasis, also known as renal stones or kidney stones, is the formation of solid concretions in the urinary tract, most often within the kidney. It is a common condition with lifetime risk that varies by population and a high tendency to recur. Men are affected more often than women, and symptoms may be present or silent until complications such as obstruction occur.

Stones form when urine becomes supersaturated with stone‑forming substances. The most common types are calcium oxalate and calcium phosphate stones; less common are uric acid stones, struvite stones (infection-related), and cystine stones in certain metabolic disorders.

Clinical presentation ranges from no symptoms to sudden, severe flank or groin pain, often with hematuria, nausea, and vomiting. Fever can indicate infection. Diagnosis typically uses imaging; non-contrast CT is a widely used, highly sensitive test, while ultrasound or plain radiography may be employed in pregnancy or specific populations. Urinalysis and laboratory studies help identify risk factors, and stone composition can be determined after passage or removal.

Management depends on stone size, location, and symptoms. Small stones often pass spontaneously with hydration and analgesia; medical expulsive therapy may aid passage. Larger stones or obstructed kidneys may require intervention such as extracorporeal shock wave lithotripsy, ureteroscopy with laser lithotripsy, or percutaneous nephrolithotomy. Antibiotics are used for infection-related stones.

Prevention focuses on high fluid intake and dietary measures to reduce stone formation, including moderating sodium, oxalate, and animal protein intake as appropriate, and treating metabolic abnormalities. Pharmacologic prevention may include thiazide diuretics for hypercalciuria, potassium citrate for hypocitraturia, or allopurinol for uric acid stones. The prognosis is generally favorable with appropriate treatment, though recurrence remains a concern.