Kidney Stones: Symptoms, Causes, Diagnosis & Treatment Options

What Are Kidney Stones?

Hard deposits of minerals and salts (calcium oxalate, uric acid, struvite, cystine) that form in kidneys. They vary from sand-grain to golf-ball size. Small stones may pass unnoticed; larger ones cause severe pain and blockage.

Common Symptoms

• Severe, wave-like pain in flank, lower back, abdomen, groin (renal colic).
• Painful, urgent, or frequent urination.
• Hematuria: Pink, red, or brown urine.
• Cloudy or foul-smelling urine.
• Nausea & vomiting.
• Fever & chills (sign of infection — emergency).
• Difficulty urinating or low output (obstruction).

Key Causes & Risk Factors

• Dehydration: Low urine volume → concentrated stone-forming salts.
• Diet: High sodium, animal protein, oxalate-rich foods (spinach, nuts, chocolate), low calcium intake (paradoxically increases oxalate absorption).
• Obesity & metabolic syndrome.
• Family/personal history.
• Medical conditions: Hyperparathyroidism, gout, recurrent UTIs, Crohn's, gastric bypass.
• Medications: Certain diuretics, calcium-based antacids, topiramate, indinavir.

Diagnosis

• Non-contrast CT scan (gold standard): Detects all stone types, size, location, obstruction.
• Ultrasound: No radiation; good for pregnant women, children. Misses small/ureteric stones.
• Urinalysis: Blood, crystals, infection signs.
• Blood tests: Creatinine, electrolytes, calcium, uric acid.
• Stone analysis (if passed): Guides prevention.

Treatment

Small Stones (<5–6 mm) — Conservative

• Hydration: 2.5–3 L urine/day.
• Pain control: NSAIDs (ketorolac, ibuprofen) ± opioids.
• Medical expulsive therapy: Tamsulosin (alpha-blocker) relaxes ureter — increases passage rate.
• Strain urine to catch stone for analysis.

Larger Stones or Complications — Intervention

• ESWL (Shock Wave Lithotripsy): Non-invasive; breaks stone with sound waves. Best for renal stones <2 cm.
• Ureteroscopy (URS) + Laser: Scope via urethra/bladder → laser fragmentation. High success for ureteral stones.
• PCNL (Percutaneous Nephrolithotomy): Keyhole surgery for large (>2 cm) or complex renal stones.
• Open/Laparoscopic surgery: Rare, for anatomic anomalies or failed minimally invasive.

Prevention (After Stone Passage/Removal)

• Hydration: Goal >2.5 L urine/day (pale yellow urine).
• Dietary: Normal calcium (1000–1200 mg/day), low sodium (<2.3 g/day), moderate animal protein, limit high-oxalate foods if calcium oxalate stones.
• Citrate: Lemon/lime juice (4 oz/day) or potassium citrate Rx — inhibits crystallization.
• Treat underlying metabolic disorders (hypercalciuria, hyperuricosuria, hypocitraturia) per 24-hr urine study.

Red flags — seek ER: Fever with flank pain, uncontrolled vomiting, solitary kidney with obstruction, known large stone with worsening symptoms.