Urolithiasis: Causes, Symptoms and Treatment

What is Urolithiasis?

Urolithiasis is the medical term for the formation of stones (calculi) anywhere in the urinary tract. These stones can develop in the kidneys (nephrolithiasis), the ureters (ureterolithiasis), the bladder (cystolithiasis), or the urethra. Urolithiasis is one of the most common urological conditions worldwide and affects men more frequently than women.

Causes and Risk Factors

Urinary stones form when certain mineral salts and other substances reach high concentrations in the urine and begin to crystallize into solid deposits. Key risk factors include:

• Insufficient fluid intake: Concentrated urine promotes stone formation.
• Diet: High consumption of oxalate-rich foods (e.g., spinach, nuts), animal protein, and table salt increases risk.
• Genetic predisposition: A family history of kidney stones is a known risk factor.
• Metabolic disorders: Such as hyperparathyroidism, gout, or cystinuria.
• Chronic urinary tract infections: Promote the formation of struvite stones.
• Certain medications: Such as diuretics or high-dose calcium and vitamin D supplements.
• Anatomical abnormalities: Such as urinary tract obstructions.

Types of Urinary Stones

• Calcium oxalate stones: The most common type, accounting for approximately 70-80% of all cases.
• Calcium phosphate stones: Often associated with metabolic disorders.
• Uric acid stones: Develop when uric acid levels are elevated, for example in gout.
• Struvite stones (infection stones): Caused by urinary tract infections with certain bacteria.
• Cystine stones: Rare; caused by the inherited metabolic disorder cystinuria.

Symptoms

Small stones can remain asymptomatic for a long time. Once a stone moves into the ureter, the following symptoms may occur:

• Renal colic: Extremely intense, wave-like flank pain that may radiate to the groin, scrotum, or labia.
• Hematuria: Blood in the urine, either visible or detectable only under a microscope.
• Nausea and vomiting
• Painful or frequent urination
• Fever and chills (when infection is present -- a medical emergency).

Diagnosis

Urolithiasis is diagnosed using a combination of:

• Medical history and physical examination: The characteristic pain pattern is highly suggestive.
• Urinalysis: Detection of blood, bacteria, or crystals in the urine.
• Imaging: Low-dose CT of the abdomen is the gold standard for stone detection. Ultrasound and X-rays are used as supplementary tools.
• Blood tests: Measurement of kidney function, uric acid, calcium, and other relevant parameters.
• Stone analysis: Passed stones are chemically analyzed to determine their composition.

Treatment

Conservative Management

Small stones (under approximately 5 mm) can often pass spontaneously. Treatment measures include:

• High fluid intake (at least 2-3 litres per day)
• Pain management with analgesics and antispasmodics
• Alpha-blockers to facilitate stone passage

Interventional and Surgical Treatment

• Extracorporeal shock wave lithotripsy (ESWL): Stones are fragmented from outside the body using focused shock waves.
• Ureteroscopy (URS): Endoscopic removal of stones from the ureter or kidney.
• Percutaneous nephrolithotomy (PCNL): Surgical removal of large kidney stones through a small incision in the skin.
• Laparoscopic or open surgery: Reserved for very large or complicated stones.

Prevention and Metaphylaxis

To reduce the risk of recurrence, the following measures are recommended:

• Adequate fluid intake (target urine output: more than 2 litres per day)
• Dietary adjustments based on stone type
• Medical metaphylaxis (e.g., allopurinol for uric acid stones, alkaline citrate to alkalinize urine)
• Regular urological follow-up examinations

References

1. European Association of Urology (EAU) - Guidelines on Urolithiasis (2024). Available at: https://uroweb.org/guidelines/urolithiasis
2. Turk C, Neisius A, Petrik A et al. - EAU Guidelines on Urolithiasis. European Urology, 2016.
3. World Health Organization (WHO) - Chronic kidney disease and urological disorders. Available at: https://www.who.int