A 38-year-old man presents to the emergency department with acute right flank pain radiating to the groin, associated with nausea and two episodes of vomiting. He has a history of recurrent kidney stones. On examination, he is restless, with costovertebral angle tenderness on the right. Urinalysis shows microscopic hematuria. Non-contrast CT (NCCT) abdomen reveals a 6 mm stone in the right distal ureter with mild hydronephrosis. Serum creatinine is 1.0 mg/dL. What is the most appropriate initial management?

Explanation

## Management of Distal Ureteric Stones **Key Point:** Small distal ureteric stones (< 10 mm) in patients with normal renal function and no signs of infection or complete obstruction have a high spontaneous passage rate (70–90%) and should be managed conservatively as first-line. ### Rationale for Conservative Management 1. **Stone size and location:** 6 mm stones in the distal ureter have excellent spontaneous passage rates, especially in men. 2. **Absence of infection:** No fever or pyuria; no indication of obstructive pyelonephritis. 3. **Preserved renal function:** Serum creatinine is normal; mild hydronephrosis does not mandate urgent intervention. 4. **Pain control and hydration:** NSAIDs (e.g., indomethacin) reduce ureteric peristalsis and promote passage; adequate hydration increases urine output. ### Conservative Protocol - Analgesics (NSAIDs preferred over opioids to preserve ureteric contractility) - Adequate hydration (oral or IV depending on tolerance) - Antiemetics as needed - Follow-up imaging (ultrasound or NCCT) at 4 weeks - Urine straining to capture passed stone - Urgent intervention if fever, worsening renal function, or complete obstruction develops **High-Yield:** The "STONE" score (size, Timing, Obstruction, New onset, Ethnicity) helps predict spontaneous passage; distal stones < 10 mm have > 70% passage rate within 4 weeks. **Clinical Pearl:** Tamsulosin (alpha-blocker) may be offered as adjunctive therapy to relax the ureteric smooth muscle and facilitate stone passage, though evidence is mixed. ### When to Intervene Urgently | Indication | Action | |---|---| | Fever + obstruction (obstructive pyelonephritis) | Percutaneous nephrostomy or ureteric stent + antibiotics | | Solitary kidney + obstruction | Urgent decompression | | Acute renal failure | Urgent decompression | | Intractable pain/vomiting despite analgesia | Ureteroscopy | | Stone > 10 mm or proximal location | Ureteroscopy or ESWL | **Warning:** Do NOT perform ureteroscopy on every stone; this increases morbidity (ureteric perforation, stricture) without benefit in small distal stones with high spontaneous passage rates.