Njursten

Njursten, or kidney stones, are hard mineral deposits that form in the kidneys or along the urinary tract. They vary in size from sand grains to large stones and may be asymptomatic or cause severe pain when they move.

Most stones are calcium-based (calcium oxalate or calcium phosphate). Other types include uric acid stones, struvite stones linked to infection, and cystine stones (rare). Risk factors include dehydration, high-sodium or high-protein diets, obesity, certain medical conditions such as hyperparathyroidism, metabolic disorders, and family history. Some medications can promote stone formation.

Symptoms usually appear when a stone irritates the urinary tract: sudden, intense flank or groin pain, blood in urine, nausea, vomiting, and a frequent urge to urinate. Fever or chills may indicate infection. Diagnosis uses urinalysis, blood tests, and imaging such as non-contrast CT or ultrasound; stone composition can be determined if the stone is passed.

Treatment depends on size and symptoms. Small stones often pass with fluids and analgesia. Medical expulsive therapy with alpha-blockers can help. Larger stones or obstructed or infected stones require procedures such as extracorporeal shock wave lithotripsy (ESWL), ureteroscopy with laser lithotripsy, or percutaneous nephrolithotomy. Infections require antibiotics and obstruction may need drainage.

Prevention focuses on hydration and diet tailored to stone type. General recommendations include high fluid intake, reduced sodium, moderated animal protein, and adequate urinary citrate. For calcium oxalate stones, limiting oxalate-rich foods helps; for uric acid stones, reducing purines is advised. Regular follow-up reduces recurrence risk.