A 40-year-old woman presented with dyspnoea and lowered level of consciousness. Three months before presentation she had underwent craniotomy for an episode of acute subdural hematoma caused by a severe neurotrauma. Her temperature was 37.3°C, she had no focal neurological deficits or neck stiffness, and the score on the Glasgow Coma Scale was 9 (E2M5V2). Cranial CT showed obstruction hydrocephalus with hypodensities consistent with airbubbles in the lateral ventricles, but no air in the proximity of the skull defect resulting from the craniotomy. External ventricular drainage was performed and cerebrospinal fluid (CSF) examination showed 126 327 leucocytes per μl, a protein level of 26.28 g/l and a glucose level of <0.1 mmol/l. CSF culture grew Klebsiella pneumoniae, a gas producing bacterium. Despite antibiotic treatment with meropenem, ceftriaxone and intraventricular gentamicin and supportive therapy, our patient deteriorated and died 3 weeks after admission. The family did not give consent for autopsy.