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Bacterascites — RACP Adult Medicine MCQ

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HardInfectious DiseasesBacterascitesRACP Adult Medicine

A 68-year-old man with chronic liver disease presents with a temperature of 38.5°C. He has no localising symptoms. His ascitic fluid PMN count is 180 cells/mm³ (below the SBP threshold). Blood cultures are negative. Urine and CXR are unremarkable. What is the most common source of fever in cirrhotic patients without an obvious focus?

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Correct answer: C — Spontaneous bacterial peritonitis (even with PMN <250 as culture may be positive)

In cirrhotic patients, culture-negative neutrocytic ascites (PMN ≥250) or bacterascites (positive culture with PMN <250) can both cause fever. The key teaching point is that a PMN count of 180 is below the diagnostic threshold for SBP (≥250) but ascitic fluid culture may still be positive (bacterascites). If clinical suspicion is high, empirical antibiotics should be commenced and cultures repeated. SBP prophylaxis with norfloxacin reduces recurrence in high-risk patients (prior SBP, ascitic protein <15 g/L with CKD or liver failure).

Reference: eTG – 2025 – Gastrointestinal; EASL – 2018 – Decompensated Cirrhosis Guidelines