Urinary Stones
Urinary stones, also known as urinary tract stones or calculi, are hard deposits that form when minerals and salts crystallise within the urinary system. Stones may develop in the kidneys, ureters, bladder, or, less commonly, the urethra. While some stones pass naturally without treatment, others can cause severe pain, urinary obstruction, infection, and kidney damage if left untreated. Early diagnosis allows appropriate treatment and helps reduce the risk of future stone formation.
What are Urinary Stones?
Urinary stones are solid masses made from substances normally found in urine. They form when urine becomes highly concentrated, allowing minerals such as calcium, oxalate, uric acid, or cystine to crystallise and gradually enlarge.
The main types of urinary stones include:
- Calcium stones (the most common type)
- Uric acid stones
- Struvite stones, often associated with urinary tract infections
- Cystine stones, caused by a rare inherited condition
Stones vary considerably in size, from tiny crystals that pass unnoticed to large stones that obstruct urine flow and require surgical treatment.
What are the Symptoms of Urinary Stones?
Symptoms depend on the size and location of the stone. Small stones may produce no symptoms until they begin moving through the urinary tract.
Common symptoms include:
- Sudden, severe pain in the back, side, or lower abdomen
- Pain that radiates to the groin
- Blood in the urine (haematuria)
- Pain or burning during urination
- Frequent urge to urinate
- Difficulty passing urine
- Cloudy or foul-smelling urine
- Nausea and vomiting
- Fever and chills if infection is present
- Difficulty passing urine or complete urinary blockage in severe cases
Pain from a stone, often called renal colic, may come in waves as the stone moves through the ureter.
What Causes Urinary Stones?
Several factors increase the likelihood of developing urinary stones.
Common causes and risk factors include:
- Inadequate fluid intake or dehydration
- Diets high in salt
- High intake of animal protein
- Foods rich in oxalate, such as spinach and nuts
- Obesity
- Family history of kidney stones
- Certain metabolic disorders
- Recurrent urinary tract infections
- Gout
- Hyperparathyroidism
- Certain medications
- Inherited conditions such as cystinuria
- Previous history of urinary stones
Many patients develop stones due to a combination of genetic and lifestyle factors.
How are Urinary Stones Diagnosed?
A urologist will evaluate your symptoms and perform investigations to confirm the diagnosis and identify the stone's size and location.
Diagnostic tests may include:
- Medical history and physical examination
- Urine analysis
- Blood tests to assess kidney function and mineral levels
- CT scan, which is the most accurate imaging test for urinary stones
- Ultrasound scan
- Plain abdominal X-ray (KUB) for certain stone types
- Stone analysis if a stone has been passed
- Metabolic urine testing in patients with recurrent stones
These investigations also help determine the most appropriate treatment strategy.
What are the Treatment Options for Urinary Stones?
Treatment depends on the size, location, composition of the stone, and the severity of symptoms.
Treatment options may include:
- Increasing fluid intake to encourage stone passage
- Pain-relieving medication
- Medication to relax the ureter and facilitate stone passage
- Antibiotics if infection is present
- Observation for small stones likely to pass naturally
- Extracorporeal shock wave lithotripsy (ESWL) to break stones into smaller fragments
- Ureteroscopy with laser stone fragmentation
- Percutaneous nephrolithotomy (PCNL) for large or complex kidney stones
- Bladder stone removal using minimally invasive endoscopic techniques
- Surgical intervention in selected complex cases
- Dietary modifications to reduce the risk of recurrence
- Long-term medications for patients with recurrent stone disease or metabolic abnormalities
Following treatment, your urologist may recommend further evaluation to identify why the stone developed and how future stones can be prevented. Drinking plenty of fluids, maintaining a healthy diet, and managing underlying medical conditions can significantly reduce the risk of recurrence. Regular follow-up is particularly important for patients who have experienced multiple stone episodes, as urinary stones have a tendency to recur without appropriate preventive measures.