Kidney stones are a common urological problem worldwide that causes severe pain and discomfort. The lifetime risk is about 10% with most stones occurring in the upper urinary tract. The overall male: female ratio of kidney stone disease is 2:1. Stone disease is frequently recurrent, with over 50% of patients developing recurrence within 10 years.
Causes and Risk Factors
Dehydration
Dietary factors – High salt, protein or oxalate rich food
Hypercalcaemia – The most common causes of hypercalcaemia leading to stone formation are – primary hyperparathyroidism, vitamin D ingestion and Sarcoidosis. Of these primary hyperparathyroidism is the most common cause of stones
Hypercalciuria – This is by far the most common metabolic abnormality detected in calcium stone formers. Causes of hypercalciuria include hypercalcaemia, an excessive dietary intake of calcium, excessive resorption of calcium from the skeleton (such as occurs with prolonged immobilization or weightlessness), idiopathic hypercalciuria
Hyperoxaluria – There are 2 inborn errors of glyoxalate metabolism that cause increased endogenous oxalate biosynthesis and are inherited in an autosomal recessive manner and in both the types, calcium oxalate stone formation occurs.
Hyperuricaemia and hyperuricosuria
Cystinuria – Cystinuria results in the formation of cystine stones.
Primary renal diseases such as Polycystic renal disease
Certain medications
Classification of stones
- Calcium oxalate and calcium phosphate stones – the most common, often linked to hypercalciuria
- Uric acid stones – associated with acidic urine and high purine diets.
- Struvite stones – often secondary to urinary tract infections with urease-producing bacteria
- Cystine stones – rare, caused by inherited defects in amino acid transport
Symptoms:
Pain is the most common symptom and maybe sharp or dull, constant, intermittent or colicky
Nausea and vomiting due to pain
Haematuria (gross or microscopic)
Dysuria or urinary frequency
Occasionally asymptomatic, detected incidentally on imaging
Urinary tract infection
Urinary tract obstruction
Treatment Options:
- Non-surgical management
- Pain management – NSAIDs are commonly used
- Adequate hydration – Patients are advised to drink 2-3 litres of water per day to promote stone passage
- Medical Expulsive Therapy (MET) – Alpha-blockers such as tamsulosin are often used to facilitate stone passage.
- Surgical management
- Extracorporeal Shock Wave Lithotripsy – a non-invasive treatment uses high energy sound waves to break stones into tiny pieces that can then pass in the urine.
- Uteroscopy – a thin, flexible tube (ureteroscope) is passed through the urethra and bladder to the stone; the stone can then be removed or broken up using a laser.
- Percutaneous Nephrolithotomy (PCNL) – For larger stones, a tube is inserted directly into the kidney through a small incision in the back through the skin, and the stone is removed or fragmented.
Prevention:
The cornerstone of kidney stone prevention is maintaining adequate hydration, with a daily fluid intake sufficient to produce at least 2–2.5 liters of urine. Dietary modifications also play a critical role, including reducing sodium and animal protein intake while ensuring adequate dietary calcium to bind oxalate in the gut. Limiting high-oxalate foods, moderating purine-rich diets, and increasing consumption of fruits and vegetables help reduce urinary stone-forming risk. Pharmacological interventions such as thiazide diuretics, potassium citrate, or allopurinol may be considered in recurrent stone formers with specific metabolic abnormalities.
