nefrolitiasis

Nefrolitiasis, or nephrolithiasis, is the formation of stones in the kidney from crystallization of minerals and organic compounds in urine. Stones may form in the kidney or travel through the urinary tract, potentially causing obstruction, severe pain, and infection.

Most stones are calcium-based, typically calcium oxalate or calcium phosphate. Other types include uric acid stones, struvite stones associated with infection, and cystine stones in cystinuria. Predisposing factors include dehydration, concentrated urine, metabolic abnormalities (hypercalciuria, hyperoxaluria, hyperuricosuria), infections, certain medications, and genetics.

Symptoms vary with size and location. Common manifestations are sudden flank or groin pain (renal colic), hematuria, nausea or vomiting, and urinary symptoms. Fever or chills suggests infection or obstruction.

Diagnosis typically uses urinalysis and noncontrast CT, which is highly sensitive for stones. Ultrasound may be used in certain patients. Stone size and location guide management.

Treatment aims to relieve pain, prevent complications, and remove the stone. Small stones often pass with hydration and analgesia; larger stones may require ESWL, ureteroscopy with stone extraction, or percutaneous nephrolithotomy. Medical expulsive therapy with alpha-blockers can help distal ureteral stones.

Prevention emphasizes hydration and dietary measures: moderate sodium intake, balanced calcium, reduced oxalate and animal protein in susceptible individuals, and citrate supplementation or medications in selected patients. A metabolic workup after recurrence informs personalized prevention.