What is the appropriate initial management for an adult male with acute distal ureteric colic from a 4.6 mm stone radiating to the penis?

Management of Acute Distal Ureteric Colic from 4.6mm Stone

Administer intramuscular diclofenac 75 mg immediately to achieve pain relief within 30 minutes, as NSAIDs are superior to opioids for renal colic and reduce the need for additional analgesia. 1, 2

Immediate Pain Management

First-Line Analgesia

• NSAIDs (specifically diclofenac 75 mg IM) are the gold standard for acute ureteric colic because they reduce ureteric spasm, provide superior pain control compared to opioids, and cause less vomiting 1, 2, 3
• The intramuscular route is preferred because oral and rectal administration are unreliable in the acute setting, and IV access may be impractical 1, 2
• Pain relief should be achieved within 30 minutes of administration 1, 2
• Acceptable pain control must be maintained for at least 6 hours 2

Second-Line Options (When NSAIDs Contraindicated)

• Use an opioid combined with an antiemetic (morphine sulfate plus cyclizine) 1, 2
• Avoid pethidine due to high rates of vomiting and need for additional analgesia 1
• Alternative opioids include hydromorphone, pentazocine, or tramadol 1, 4

Critical Red Flags Requiring Immediate Hospital Admission

Admit immediately if any of the following are present:

• Fever or signs of systemic infection (possible sepsis with obstructed kidney) 1, 2, 3
• Shock or hemodynamic instability 1, 2
• Anuria or severe oliguria (≤1 void in 24 hours) 1, 2
• Failure of pain control within 60 minutes of initial analgesia 1, 2, 4
• Persistent vomiting despite treatment 2

Emergency Decompression Indications

• If sepsis and/or anuria are present with obstruction, perform urgent decompression via percutaneous nephrostomy or ureteral stenting before definitive stone treatment 1, 2
• Collect urine for culture before and after decompression, and start empiric broad-spectrum antibiotics immediately 1

Medical Expulsive Therapy for This 4.6mm Stone

Do NOT use alpha-blockers for this stone size. Medical expulsive therapy with alpha-blockers (tamsulosin) provides the greatest benefit for stones >5 mm in the distal ureter 1, 2. Since this stone is 4.6 mm, it falls below the threshold where MET shows strong efficacy, and approximately 90% of stones <5 mm pass spontaneously without intervention 1, 3.

Follow-Up Protocol

Immediate Follow-Up

• Telephone the patient 1 hour after initial assessment to verify analgesic effectiveness 1, 2
• If pain recurs abruptly or severely, arrange immediate hospital admission 1, 2

Imaging and Specialist Referral

• Arrange fast-track imaging (non-contrast CT or ultrasound) within 7 days to confirm stone location, size, and degree of obstruction 1, 2, 3
• Schedule urgent urology outpatient appointment within 14 days if stone is still present on imaging 1

Home Management Instructions

Provide the following guidance for outpatient management:

• Maintain high fluid intake (>2 liters/day) 3
• Strain all urine through a tea strainer or gauze to capture the stone for laboratory analysis 1, 2
• Provide a limited supply of oral or rectal NSAIDs for recurrent pain episodes 1, 2
• Instruct the patient to contact you immediately if pain worsens, fever develops, or urination stops 1, 2

Stone Passage Expectations

• Approximately 90% of stones <5 mm pass spontaneously 1, 2, 3
• Distal ureteral stones (causing pain radiating to the penis) have higher spontaneous passage rates than proximal stones 3, 5
• However, 34% of patients with stones <5 mm may still require surgical intervention due to persistent pain, with larger size (closer to 5 mm) and proximal location being the strongest predictors 5

Common Pitfalls to Avoid

• Do not delay analgesia while waiting for imaging or diagnostic confirmation 6
• Do not use high-volume IV fluids (2-3 liters over 4-6 hours) as there is no evidence this expedites stone passage or improves pain control 7
• Screen for NSAID contraindications including low GFR, cardiovascular disease, gastrointestinal bleeding risk, and use the lowest effective dose 1
• In patients over 60 years, actively exclude leaking abdominal aortic aneurysm as an alternative diagnosis 1, 2
• Do not issue unlimited quantities of oral analgesics due to potential for drug misuse 1, 6