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Renal & Urinary System

Renal Colic

Acute, severe, colicky flank pain caused by the passage or obstruction of a urinary stone (calculus) in the ureter.

Also known as: Kidney Stone Pain, Ureteric Colic

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Referral and warning signs

When to refer

Urgent referral to Urology/Hospital (HC4/H/RR) if: Severe pain unresponsive to analgesia. Signs of infection (fever, chills) with obstruction (UROLOGICAL EMERGENCY). Acute kidney injury / Anuria. Stone unlikely to pass spontaneously (>7-10mm, persistent obstruction). Solitary kidney with obstruction.

Red flags

  • Fever or chills with flank pain (infected hydronephrosis/pyelonephritis)
  • Severe pain refractory to analgesia
  • Anuria or rapidly worsening renal function
  • Known solitary kidney with obstruction
  • Signs of sepsis

Signs and symptoms

  • Sudden onset of severe, colicky (waxing and waning) pain.
  • Pain typically starts in the flank (loin/costovertebral angle) and radiates anteriorly towards the groin, testis (men), or labia (women).
  • Patient often restless, unable to find comfortable position.
  • Nausea and vomiting common.
  • Haematuria (microscopic or gross).
  • May have associated dysuria, frequency, urgency if stone is near bladder (vesicoureteric junction).
  • Fever and chills suggest associated infection (infected hydronephrosis/pyelonephritis) - Urological Emergency.

Risk factors

  • Dehydration / Low fluid intake
  • High dietary intake of animal protein, sodium, oxalate (spinach, rhubarb, nuts, chocolate), purines (meat, seafood)
  • Family history of kidney stones
  • Personal history of previous stones
  • Certain medical conditions: Hyperparathyroidism, Renal tubular acidosis, Gout, Cystinuria, Inflammatory bowel disease, Urinary tract infections (struvite stones), Urinary tract structural abnormalities.
  • Certain medications (e.g., diuretics, topiramate, protease inhibitors).
  • Obesity, metabolic syndrome.
  • Hot climate.

Diagnosis

Clinical assessment

Diagnosis strongly suspected based on characteristic severe, colicky, radiating flank pain. Assess for CVA tenderness. Rule out red flags (fever). Differential diagnosis: Pyelonephritis, Appendicitis, Diverticulitis, Cholecystitis, Ovarian torsion/ruptured cyst, Ectopic pregnancy, Testicular torsion, Aortic aneurysm/dissection, Musculoskeletal back pain.

Investigations

  • Urinalysis: Haematuria (microscopic or gross) present in ~85% cases. May show crystals, signs of infection (WBCs, nitrites). pH may give clue to stone type.
  • Imaging: Non-Contrast Helical CT Scan (Abdomen/Pelvis - CT KUB): Gold standard. Highly sensitive and specific for detecting stones (size, location), assessing for hydronephrosis (obstruction), and ruling out alternative diagnoses.
  • - Kidney Ultrasound: Alternative initial imaging, especially in pregnancy or children. Good for detecting hydronephrosis and stones within kidney/proximal ureter/VUJ. Less sensitive for mid-ureteric stones.
  • - Plain Abdominal X-ray (KUB): Can detect radio-opaque stones (calcium oxalate/phosphate, struvite - ~80-90% stones), but misses radiolucent stones (uric acid, cystine) and obscured by bowel gas/bone.
  • Blood tests: Creatinine/eGFR (assess renal function), Electrolytes, Calcium, Uric acid (assess potential underlying cause). CBC (leucocytosis suggests infection).

Diagnostic criteria

Characteristic clinical presentation +/- haematuria, confirmed by imaging demonstrating stone and/or hydronephrosis.

Management

Non-pharmacological management

  • Pain Management (Acute):
  • - Hydration: Encourage oral fluids IF patient can tolerate AND stone likely to pass. IV fluids if vomiting/unable to drink.
  • Strain Urine: To catch stone for analysis.
  • Medical Expulsive Therapy (MET): For distal ureteric stones <10mm (controversial, specialist decision). Alpha-blockers (e.g., Tamsulosin) or Calcium Channel Blockers (Nifedipine) may facilitate stone passage.
  • Interventional Procedures (For stones unlikely to pass, persistent pain, obstruction, infection, AKI):
  • - Extracorporeal Shock Wave Lithotripsy (ESWL): Non-invasive, uses shock waves to break stone.
  • - Ureteroscopy (URS) with laser lithotripsy/basket extraction: Scope passed up ureter.
  • - Percutaneous Nephrolithotomy (PCNL): For large kidney stones.
  • - Surgical removal (rarely needed).

Pharmacological treatment

  • Analgesia: NSAIDs (e.g., Diclofenac 75mg IM, Ketorolac IV/IM, Ibuprofen PO) are highly effective (reduce ureteric spasm/inflammation). Use cautiously if renal impairment/PUD/contraindicated.
  • - Opioids (e.g., Pethidine 50-100mg IM, Morphine IV) for severe pain or if NSAIDs contraindicated.
  • Antiemetics (e.g., Metoclopramide 10mg IV/IM) if nausea/vomiting.
  • Medical Expulsive Therapy (MET): Tamsulosin 0.4mg OD (or other alpha-blocker).
  • Antibiotics: ONLY if concurrent UTI/pyelonephritis suspected (see relevant sections). Treat infection URGENTLY before considering definitive stone removal if obstructed.

Monitoring

Monitor pain control. Monitor for stone passage (strain urine). Monitor renal function if obstructed or AKI suspected. Follow-up imaging to confirm stone passage or assess response to intervention.

Complications

  • Persistent pain
  • Urinary tract infection (UTI) / Pyelonephritis / Urosepsis (especially if obstructed)
  • Hydronephrosis (swelling of kidney due to obstruction)
  • Acute Kidney Injury (AKI) (esp. with bilateral obstruction or obstruction in solitary kidney)
  • Chronic Kidney Disease (CKD) (from recurrent stones, chronic obstruction, recurrent infections)
  • Ureteral stricture (rare, post-stone/intervention)

Prevention

  • Increased Fluid Intake: Aim urine output >2-2.5 L/day (most important measure).
  • Dietary Modifications (based on stone analysis if available):
  • - Calcium Oxalate stones: Moderate calcium intake (do NOT restrict severely), limit dietary oxalate (spinach, rhubarb, nuts, chocolate, tea), limit animal protein, limit sodium.
  • - Uric Acid stones: Limit purine intake (organ meats, red meat, seafood), alkalinize urine (potassium citrate), consider Allopurinol.
  • - Struvite stones: Treat underlying UTI, consider long-term antibiotics if recurrent.
  • - Cystine stones: High fluid intake, urine alkalinization, specific medications (Tiopronin, Penicillamine - specialist).
  • Medications: Thiazide diuretics (reduce calcium excretion), Potassium citrate (increase urine citrate, alkalinize), Allopurinol (for hyperuricosuria/uric acid stones).

Patient education

  • Explanation of renal colic and kidney stones.
  • Pain management plan.
  • Importance of hydration.
  • Need to strain urine to catch stone.
  • Likelihood of spontaneous passage based on size/location.
  • Explanation of potential interventions (ESWL, URS, PCNL).
  • Dietary and fluid recommendations for prevention based on stone type/risk factors.
  • Signs of complications (infection, worsening pain) requiring urgent return.

Uganda-specific notes

Stones common, often calcium oxalate. Access to CT KUB, ESWL, Ureteroscopy, PCNL is limited. Ultrasound used for initial assessment (hydronephrosis). Management focuses on pain control, hydration, and referral for persistent/complicated stones. Infected obstructed kidney is a surgical emergency.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 7, Section 7.2.4

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