What Are Kidney Stones?
Kidney stones are hard mineral deposits that form inside the kidneys when urine becomes concentrated. They range from a grain of sand to several centimetres. About 1 in 10 people develop a stone at some point, and recurrence is common without lifestyle changes.
Types of Stones
- Calcium oxalate — most common (~80%), linked to low fluid intake and high-oxalate diet.
- Uric acid — commoner in men, gout, and high-protein diets.
- Struvite — usually follow recurrent urinary tract infections.
- Cystine — rare, caused by a hereditary amino acid transport defect.
Stone type analysis after passage or surgery guides targeted prevention, so always bring your stone to the lab if you catch it.
Causes & Risk Factors
Key Risk Factors
- Low daily fluid intake — the single most modifiable risk
- High-sodium or high-animal-protein diet
- Obesity and sedentary lifestyle
- Family history of kidney stones
- Previous stone (40–50% recurrence within 5 years if untreated)
- Conditions: hyperparathyroidism, recurrent UTIs, Crohn's disease, gout
Recognising Symptoms
Small stones may pass painlessly. Larger or obstructing stones cause:
- Severe, wave-like flank pain radiating to the groin (renal colic)
- Blood in urine — visible or detected on dipstick
- Nausea and vomiting with pain episodes
- Frequent, urgent or burning urination as the stone nears the bladder
⚠ Seek Urgent Care If You Have
Fever with flank pain, inability to pass urine, or uncontrollable pain. An infected obstructed kidney is a urological emergency requiring immediate drainage.
Treatment Options
- Watchful waiting + alpha-blocker — for stones <5 mm with adequate hydration and pain relief.
- ESWL — non-invasive shock waves break stones up to 15 mm without any incision.
- Ureteroscopy (URS) — flexible camera passed through the urethra to laser-fragment stones in the ureter or kidney. Day procedure.
- PCNL — for large (>20 mm) or staghorn stones via a small back puncture. Read our PCNL guide →
Diagnosed with a kidney stone?
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Book a consultation with Dr. Azhar Anwar to discuss the right treatment for your stone.
Prevention: 5 Key Steps
- Drink 2.5–3 litres of water daily — aim for pale, straw-coloured urine all day.
- Reduce salt — high sodium raises urinary calcium. Limit processed food and added salt.
- Moderate animal protein — excess red meat raises uric acid; balanced portions help.
- Keep dietary calcium — calcium in food binds gut oxalate and reduces absorption. Don't cut dairy.
- Limit high-oxalate foods — spinach, nuts, strong tea in moderation if you form calcium oxalate stones.