NDM-Producing Escherichia coli subdural empyema mimicking chronic subdural hematoma: a case report

Subdural empyema is a life-threatening intracranial infection that may mimic chronic subdural hematoma on non-contrast computed tomography (CT), delaying diagnosis and source control. Intracranial infection caused by New Delhi metallo-β-lactamase (NDM)-producing Escherichia coli is rare and may be overlooked when bloodstream infection appears microbiologically controlled.

An 82-year-old man presented with fever and progressive neurological deterioration. Chest computed tomography (CT) suggested right lower lobe pneumonia, whereas serial head CT scans showed a left frontotemporoparietal subdural collection that was repeatedly interpreted as chronic subdural hematoma. Blood culture yielded multidrug-resistant Escherichia coli, and blood metagenomic next-generation sequencing (mNGS) detected E. coli together with blaNDM and other resistance determinants. Despite microbiologically guided antimicrobial therapy and subsequent clearance of blood cultures, fever, impaired consciousness, and enlargement of the subdural lesion persisted. Burr-hole exploration on March 22 revealed yellow purulent material rather than hematoma, establishing the anatomical diagnosis of subdural empyema and providing source control. Conventional culture of the surgically obtained subdural pus also yielded multidrug-resistant E. coli, while pus mNGS detected E. coli, blaNDM, blaCTX-M, and mcr-1. At the latest follow-up, the patient was undergoing further rehabilitation at a rehabilitation hospital. His vital signs were stable, and his Glasgow Coma Scale score was 15.

Negative follow-up blood cultures do not exclude persistent compartmentalized intracranial infection. In bacteremic patients with neurological deterioration and an enlarging subdural collection, subdural empyema should be reconsidered and timely source control should not be delayed.