Urolithiasis

Urolithiasis refers to the formation of calculi (stones) within the urinary tract, including the renal calyces, renal pelvis, ureters, or urinary bladder, resulting from urine that becomes supersaturated with stone-forming salts.

Stone formation occurs when crystallization exceeds the natural inhibitory mechanisms of urine, leading to aggregation and retention of mineral deposits. Urolithiasis is a common urological condition and an important cause of acute flank pain and urinary obstruction.

Epidemiology

• Lifetime risk: 10–15% globally

• More common in males than females

• Peak age: 20–50 years

• High recurrence rate (≈50% within 5–10 years)

Types of Urinary Stones

1. Calcium oxalate stones (most common)

2. Calcium phosphate stones

3. Uric acid stones

4. Struvite stones (infection-related)

5. Cystine stones (genetic disorders)

Risk Factors

Metabolic Factors

• Hypercalciuria

• Hyperoxaluria

• Hyperuricaemia

• Low urinary citrate

• Dehydration

Dietary Factors

• Low fluid intake

• High salt intake

• Excess animal protein

• High oxalate diet

• Excess sugar intake

Medical Conditions

• Recurrent urinary tract infections

• Gout

• Obesity

• Hyperparathyroidism

• Chronic kidney disease

• Malabsorption syndromes

Environmental Factors

• Hot climate

• Excessive sweating

• Sedentary lifestyle

Genetic Factors

• Family history of stone disease

• Cystinuria

Pathophysiology

Stone formation involves:

1. Urinary supersaturation

2. Crystal nucleation

3. Crystal growth

4. Aggregation

5. Retention within urinary tract

Urinary obstruction caused by stones leads to:

• Increased intraluminal pressure

• Ureteric spasm

• Renal capsule distension → severe colicky pain

Signs and Symptoms

Classical Presentation

• Sudden onset severe flank pain (renal colic)

• Restlessness (patient unable to remain still)

• Pain radiating to groin, scrotum, or labium

• Nausea and vomiting

Urinary Symptoms

• Haematuria (microscopic or gross)

• Dysuria

• Urinary frequency or urgency

Complicated Disease

• Fever and chills (infection)

• Reduced urine output

• Signs of sepsis

• Acute kidney injury

Diagnostic Criteria

Diagnosis is based on clinical features supported by imaging and laboratory findings:

• Sudden acute flank colic

• Nausea and vomiting

• Haematuria

• Referred genital pain

• Urinalysis showing infection or microscopic haematuria

• Ultrasound showing acoustic shadow or obstructive uropathy (hydronephrosis/hydroureter)

• Plain abdominal X-ray detecting radio-opaque calculi

• CT urography or intravenous urogram confirming urinary tract lithiasis

Investigations

Laboratory Tests

• Urinalysis

• Urine culture

• Serum creatinine

• Blood urea nitrogen

• Electrolytes

• Serum calcium

• Serum uric acid

• Full blood count

Imaging Studies

First-line

• Ultrasound abdomen and pelvis

Gold Standard

• Non-contrast CT scan (CT KUB)

Additional Imaging

• Plain X-ray KUB

• Intravenous urography (IVU)

Management

Treatment Objectives

• Pain control

• Facilitate stone passage

• Treat infection

• Relieve obstruction

• Prevent recurrence

Pharmacological Management

Analgesia

Ibuprofen 400 mg PO 8 hourly for 3 days

OR

Tramadol injection 100 mg stat, thenTramadol 50 mg PO 8 hourly

NSAIDs are preferred as they reduce ureteric spasm and inflammation.

Medical Expulsive Therapy

For distal ureteric stones <7 mm:

Tamsulosin 0.4 mg PO once daily for 4 weeks

Enhances spontaneous stone passage by relaxing ureteric smooth muscle.

Antibiotics

Indicated when infection is present according to culture results.

Obstruction + infection = urological emergency

Non-Pharmacological Management

Hydration

• Fluid intake: 2.5–3 litres/day

• Target urine output: >2.5 litres/day

Dietary Measures

• Balanced diet rich in vegetables and fibre

• Normal calcium intake: 1–1.2 g/day

• Reduce sodium intake: 4–5 g/day

• Limit animal protein: 0.8–1.0 g/kg/day

• Reduce oxalate-rich foods when indicated

Indications for Surgical

Intervention

Referral to specialized urology centres is required when:

• Stone >7–10 mm

• Persistent severe pain

• Obstruction

• Renal impairment

• Failed conservative therapy

• Recurrent infections

• Single functioning kidney

Emergency Management

In obstructive uropathy with infection:

Immediate decompression required via:

• Percutaneous nephrostomyOR

• Ureteric Double-J (DJ) stenting

Definitive Surgical Options

• Extracorporeal Shock Wave Lithotripsy (ESWL)

• Ureteroscopy with laser lithotripsy

• Percutaneous nephrolithotomy (PCNL)

• Open or laparoscopic surgery (rare)

Complications

• Hydronephrosis

• Recurrent urinary tract infection

• Pyelonephritis

• Urosepsis

• Renal failure

• Stone recurrence

Prevention

Lifestyle Prevention

• Maintain high fluid intake

• Regular physical activity

• Weight control

Dietary Prevention

• Reduce salt intake

• Moderate animal protein consumption

• Adequate dietary calcium

• Avoid excessive oxalate foods

Medical Prevention

Based on metabolic evaluation:

• Thiazide diuretics

• Potassium citrate

• Allopurinol (uric acid stones)

Patient Education

• Early medical consultation for flank pain

• Maintain hydration daily

• Complete treatment even after pain resolution

• Regular follow-up for recurrent stones

• Dietary modification reduces recurrence risk