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Spontaneous bacterial peritonitis with acute renal deterioration — MRCEM SBA MCQ

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HardGastrointestinal and surgical emergenciesSpontaneous bacterial peritonitis with acute renal deteriorationMRCEM SBA

A 61-year-old man with alcohol-related cirrhosis and established ascites presents to the emergency department with fever and diffuse abdominal discomfort. His temperature is 38.4°C and blood pressure is 110/68 mmHg. He has mild generalised tenderness without guarding or focal peritonism; the ascites is not tense. Serum creatinine is 168 micromol/L, compared with 82 micromol/L three days ago. An immediate diagnostic ascitic tap shows a neutrophil count of 0.43 × 10⁹/L. Ascitic fluid and blood cultures have been sent but are pending. Intravenous access and an initial fluid assessment are complete. Which management plan is most appropriate now?

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

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Correct answer: D — Start intravenous antibiotics with weight-based intravenous albumin; arrange inpatient liver-team review.

The ascitic neutrophil count exceeds 0.25 × 10⁹/L, establishing spontaneous bacterial peritonitis (SBP) in this presentation. Treatment should begin while cultures are pending. His creatinine has more than doubled in three days, so preventing further renal deterioration is an immediate priority. Start intravenous antibiotics according to local policy and give intravenous albumin; UK specialty guidance recommends 1.5 g/kg within six hours of SBP diagnosis when creatinine is increased or rising, followed by 1 g/kg on day 3. He requires admission and liver-team review. A applies the separate albumin regimen used after therapeutic paracentesis; this was a diagnostic tap, and SBP-associated renal deterioration calls for weight-based dosing. B correctly prioritises antibiotics but omits indicated albumin. C substitutes imaging for albumin despite the absence of findings suggesting a surgically treatable source. CT would become important if secondary peritonitis were suspected, but it does not replace treatment here. E treats the creatinine rise as established hepatorenal syndrome and substitutes terlipressin for albumin. Renal deterioration during SBP does not establish that diagnosis, and terlipressin is not a replacement for the indicated SBP treatment.

Reference: Decompensated cirrhosis: an update of the BSG/BASL admission care bundle (2025) — https://fg.bmj.com/content/early/2025/04/18/flgastro-2025-103074?versioned=true Guidelines on the management of ascites in cirrhosis (2021) — https://gut.bmj.com/content/70/1/9 Cirrhosis in over 16s: assessment and management — full guideline (2016) — https://www.nice.org.uk/guidance/ng50/evidence/full-guideline-pdf-2546537581