What is the medical management for renal colic?

Medical Management of Renal Colic

Intramuscular diclofenac 75 mg is the first-line treatment for renal colic when the diagnosis is clear and there are no contraindications. 1

Initial Pain Management

• NSAIDs are the first-line treatment for renal colic pain, with diclofenac 75 mg intramuscularly being the preferred option due to its effectiveness and lower risk of side effects compared to opioids 1, 2
• Pain relief should be provided within 30 minutes of assessment, with complete or acceptable pain control maintained for at least six hours 1
• If NSAIDs are contraindicated (e.g., renal impairment, heart failure, pregnancy), opioids combined with an antiemetic (such as morphine sulfate with cyclizine) should be used as second-line treatment 1, 3, 4
• For patients with acute renal failure specifically, fentanyl is the safest opioid choice as it doesn't accumulate active metabolites in renal failure 3
• Combination therapy of NSAIDs plus opioids may provide better pain control than either agent alone in approximately 10% of patients with severe pain 4, 5

Monitoring Response to Treatment

• If pain is not alleviated within 60 minutes of initial analgesia, the patient should be admitted to hospital immediately 1
• Follow-up should include a telephone call one hour after initial assessment and analgesia administration to evaluate pain control 1
• Abrupt recurrence of severe pain also warrants immediate hospital admission 1

Hydration and Home Management

• Patients managed at home should drink plenty of fluids, though intensive hydration is not currently recommended 1, 6
• Patients should be instructed to void urine into a container or through a tea strainer/gauze to catch any passed stones for analysis 1, 2
• The patient should be instructed to contact the doctor if pain worsens or unexpected symptoms develop 1

Diagnostic Workup

• All patients, whether managed at home or in hospital, should be offered fast-track urological investigation with follow-up 1, 2
• Ultrasound is recommended as the primary diagnostic tool for suspected kidney stones, with non-contrast CT as the standard second-line imaging if ultrasound is inconclusive 2
• Laboratory evaluation should include urinalysis (for blood, pH, signs of infection), basic serum chemistry panel, and urine culture if infection is suspected 2

Criteria for Immediate Hospital Admission

• Patients with any of the following should be immediately admitted to hospital:
  • Failure to respond to analgesia within one hour 1
  • Fever or signs of infection 2
  • Intractable pain 1, 2
  • Solitary kidney or bilateral obstruction 2
  • Acute kidney injury 2, 3
  • Shock or systemic infection 1

Special Considerations

• For pregnant women, morphine carries a lower risk of adverse effects than NSAIDs, which should never be used during pregnancy 3, 4
• NSAIDs should be avoided in patients with heart failure, renal artery stenosis, dehydration, renal impairment, or concurrent nephrotoxic drug treatment 4, 5
• In elderly patients, lower doses of analgesics should be used with careful monitoring for adverse effects 3

Follow-up Investigations

• Key questions to address during follow-up include:
  • Was a calculus identified? If so, what was its size and location? 1, 2
  • If a calculus is still present, is intervention likely to be needed? 1
  • If no calculus is present, should alternative diagnoses be considered? 1
  • Is the patient at risk of developing further episodes? 1

Common Pitfalls to Avoid

• Delaying pain relief - analgesia should be provided within 30 minutes of assessment 1
• Using oral or rectal analgesics for initial management - these routes are considered unreliable for acute severe pain 1
• Using morphine, codeine, or meperidine in patients with renal failure - these medications can accumulate toxic metabolites 3
• Failing to arrange appropriate follow-up imaging - all patients should receive radiological evaluation within 7 days 1, 2