Causes of Kidney Stones

Kidney stones form when minerals and salts in urine clump together into hard crystals. They form more easily when urine is concentrated or when stone-forming substances are high.

Main causes and risk factors

• Not drinking enough fluid: the most common cause, especially in hot weather or with heavy sweating
• Diet: high salt, high animal protein, high sugar and a large intake of oxalate-rich foods in some people
• Family history of stones or having had a stone before
• Medical conditions: gout and high uric acid, hyperparathyroidism, inflammatory bowel disease, past bowel surgery, repeated urinary infections, diabetes and metabolic syndrome
• Inherited conditions such as cystinuria and primary hyperoxaluria
• Medicines and supplements: excess vitamin C or vitamin D, calcium pills taken without advice, some diuretics, and some HIV and epilepsy medicines
• Obesity and rapid weight loss
• Urinary tract problems: blockages, past stones and structural differences in the kidney or ureter

Why stones form

• Urine becomes saturated with calcium, oxalate, uric acid or cystine
• Low urine volume or low citrate, a natural stone blocker, makes crystals more likely to form
• Infection can cause struvite stones

Who is more at risk

Stones are more common in adults aged 20 to 50, men, and people living in hot climates.

Ayurvedic view

Ayurveda calls kidney stones ashmari and links them to Kapha with Vata and Pitta imbalance, dehydration and poor digestion. This is a traditional framework and not a modern diagnosis.

Key point

Low fluid intake plus diet and medical factors are behind most stones, and many of these can be changed.

Before your appointment

Note when the pain began, where it is, and whether you have noticed blood, fever, nausea or burning in your urine. Record how much you drink and pass urine in a day. List medicines and supplements, especially vitamin C, vitamin D, calcium and herbal products. Mention previous stones, gout, bowel surgery, urinary infections and family history. Bring earlier scans and reports. If you pass a stone, save it for analysis. Ask about tests, the stone type and a prevention plan. Call 112 for fever with pain or if you pass no urine.