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Infected obstructing ureteric stone with acute kidney injury — MRCEM SBA MCQ

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HardInfection and sepsisInfected obstructing ureteric stone with acute kidney injuryMRCEM SBA

A 57-year-old man presents with right loin pain and rigors. His temperature is 38.8°C, pulse 116/min, blood pressure 124/76 mmHg and venous lactate 1.5 mmol/L. Urine is positive for nitrites and leucocytes. Creatinine is 176 µmol/L, compared with 82 µmol/L two months ago. CT KUB shows a 4 mm right distal ureteric stone with hydroureteronephrosis; the left kidney is unobstructed. Blood and urine cultures have been taken, intravenous access established and fluid resuscitation started. He has no antibiotic allergy and has not yet received antibiotics. Which management plan is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Start intravenous antibiotics, admit, and drain the upper tract within 12 hours; defer stone removal.

Fever and rigors with an obstructing ureteric stone indicate an infected obstructed upper urinary tract. The substantial rise in creatinine adds acute kidney injury. Neither the stone’s small size, the normal contralateral kidney nor the absence of hypotension makes observation safe. He needs immediate urological involvement, intravenous antibiotics and admission for urgent source control. NICE recommends nephrostomy or ureteric stenting as soon as possible and within 12 hours of diagnosis when treating upper-tract obstruction with acute kidney injury. Either drainage route is acceptable; definitive stone removal can be planned after the infection is controlled. ([nice.org.uk](https://www.nice.org.uk/guidance/ng148/chapter/Recommendations)) A delays drainage to test the response to antibiotics, despite an established infected obstruction. C applies an early stone-treatment approach rather than prioritising drainage of the infected collecting system. D introduces repeat imaging as a condition for treatment although CT has already demonstrated the obstruction. E makes source control contingent on culture growth; cultures guide subsequent antimicrobial treatment but need not confirm an infection already evident clinically before drainage is arranged. ([nnuh.nhs.uk](https://www.nnuh.nhs.uk/publication/download/joint-trust-clinical-procedure-for-renal-tract-calculi-renal-colic-v2/))

Reference: Acute kidney injury: prevention, detection and management — recommendations 1.5.1–1.5.2 (2019) — https://www.nice.org.uk/guidance/ng148/chapter/Recommendations Clinical Procedure for the Management of Renal Colic — sections 3.2.2–3.2.4 (Approved June 2024) — https://www.nnuh.nhs.uk/publication/download/joint-trust-clinical-procedure-for-renal-tract-calculi-renal-colic-v2/