Kidney Stones
Kidney stones are hard deposits of crystals (minerals and organic material) that form inside the kidney. Many remain symptomless for years, but if a stone moves into the ureter (the tube from kidney to bladder) and causes obstruction it can produce severe pain called ureteric or renal colic.
Incidence
Kidney stones are increasingly common worldwide, affecting roughly 10% of the population. They are more frequent in men (about 12% of men versus 6% of women), though this gap is narrowing. Data suggest a lifetime prevalence near 13%, with an average age at diagnosis of about 49 years.
Symptoms
Asymptomatic: Small stones within the kidney often cause no symptoms.
Local symptoms: A dull ache or pain in the loin/flank, blood in the urine (haematuria) or recurrent urinary infections.
Ureteric (renal) colic: Sudden, severe, cramping pain as a stone obstructs the ureter—commonly described as extremely intense pain. The pain typically begins in the loin and can radiate around the abdomen to the groin or genitalia as the stone moves. Nausea and vomiting are common. When a stone reaches the bladder it may produce a persistent urge to pass urine.
Important warning signs: Any fever over 38°C or feeling generally unwell with a suspected obstructing stone requires urgent medical attention—an infected, obstructed kidney can be life‑threatening.
Notes on symptom course Pain often comes in waves and may completely subside between episodes. Absence of pain does not guarantee the stone has passed; an obstructed kidney can be painless and still at risk of damage. Follow-up imaging or urology review is important to confirm passage.
Management
Observation and medical expulsion: Small ureteric stones are commonly managed expectantly to see if they pass spontaneously. Alpha‑blocker medications are sometimes used to aid passage—evidence is mixed but guidelines often recommend them for lower ureteric stones. If a stone fails to pass within a set period (typically 2–4 weeks) or causes complications, active treatment is recommended.
Pain relief: Analgesic choice depends on medical history and allergies. Non‑steroidal anti‑inflammatory drugs (NSAIDs) such as ibuprofen or diclofenac are often most effective for colic; paracetamol may be used alongside them. In the emergency setting, stronger intravenous opioids (e.g., morphine) may be required for severe pain.
Treatment for kidney stones: Management depends on stone size, location, kidney anatomy, number of stones, prior treatment history and patient preference. Small, asymptomatic renal stones can be observed. Larger or symptomatic stones may be treated with extracorporeal shockwave lithotripsy (ESWL), ureteroscopy (URS) or percutaneous nephrolithotomy (PCNL).
Prevention
All patients should have baseline urine and blood tests to check for treatable causes. Younger patients or recurrent stone formers may need more detailed investigation, including 24‑hour urine collections. General prevention focuses on fluid and dietary measures tailored to the individual. In selected cases, the urologist may prescribe medications to reduce recurrence risk based on stone type, frequency, age and underlying causes. See the “Prevention of stones” page for more detail.