Management of Renal Colic
Prompt analgesia with intramuscular diclofenac 75 mg is the first-line treatment for renal colic when the diagnosis is clear and there are no signs of complications. 1
Initial Assessment and Diagnosis
The diagnosis of renal colic is primarily based on:
- Abrupt onset of severe unilateral flank pain radiating into the groin or genitals 1
- Examination of the abdomen to establish site of maximal tenderness
- Exclusion of other conditions such as peritonitis
- Assessment of vital signs to exclude shock and systemic infection
Warning Signs Requiring Immediate Hospital Admission
- Presence of shock
- Fever
- Oligoanuria
- Patients over 60 years (consider leaking abdominal aortic aneurysm)
- Women with delayed menses (consider ectopic pregnancy) 1
Urinalysis
- Haematuria supports the diagnosis (present in >80% of cases)
- Alternative diagnoses should be considered if urinalysis is negative
- Note: Not all patients can provide a specimen during acute pain 1
Pain Management Algorithm
First-Line Treatment
- Intramuscular diclofenac 75 mg 1
- Complete pain control should be maintained for at least 6 hours
- Intramuscular route is preferred (oral and rectal administration are considered unreliable, intravenous route impractical in primary care) 1
Alternative First-Line Treatment (When NSAIDs are Contraindicated)
- Opiate combined with an antiemetic (e.g., morphine sulfate and cyclizine) 1
- Particularly important in pregnant women, where morphine carries a lower risk than NSAIDs 2
Second-Line Treatment
- If pain is not alleviated within 60 minutes, immediate hospital admission is required 1
- In hospital settings, combination therapy of NSAIDs plus opioids may provide better pain control in about 10% of patients 2
Contraindications to NSAIDs
- Pregnancy
- Heart failure
- Renal artery stenosis
- Dehydration
- Existing renal impairment
- Concurrent treatment with nephrotoxic drugs
- Very elderly patients 2
Home Management Instructions
- Encourage high fluid intake
- Instruct patient to void urine into a container or through a tea strainer/gauze to catch any calculus 1
- Follow up with telephone call one hour after initial assessment and analgesia 1
- Patient should contact doctor if pain worsens or if unexpected symptoms develop 1
Hospital Admission Criteria
- Failure to respond to analgesia within one hour
- Abrupt recurrence of severe pain
- Presence of shock or fever 1
Follow-up Management
- Fast-track investigation initiated by hospital (within 7 days of symptom onset)
- Urgent urology outpatient appointment within a week if renal imaging shows a problem requiring intervention 1
- Investigations should determine:
- Whether a calculus was identified (size and location)
- If intervention is needed for a present calculus
- If alternative diagnoses should be considered
- Patient's risk for developing further episodes 1
Evidence Comparison
The evidence strongly supports NSAIDs as first-line treatment for renal colic. Multiple studies show NSAIDs are as effective as opioids for pain relief but with fewer adverse effects, particularly vomiting (6% with NSAIDs vs 20% with opioids) 2, 3. The Cochrane review confirms that patients treated with NSAIDs were significantly less likely to require rescue medication compared to those receiving opioids 4.
Common Pitfalls to Avoid
- Delaying analgesia (should be given within 30 minutes of assessment)
- Using oral or rectal analgesics as first-line treatment (less reliable)
- Failing to arrange hospital admission if pain persists beyond one hour
- Not considering serious alternative diagnoses in atypical presentations
- Neglecting follow-up investigations to identify the underlying cause
The management pathway described represents a consensus-based approach that bridges primary and secondary care, ensuring appropriate pain relief while facilitating timely investigation and definitive treatment 1.