Subdural false twins: concomitant appearance of subdural haematoma and spontaneous subdural empyema

A 55-year-old man was taken to the emergency department due to right arm weakness for the past 3 days and fever (39.5°C). There was no impaired consciousness, no history of trauma and meningeal signs were absent on physical examination. Blood analysis and inflammatory markers were not evocative of a systemic infection. A cranial CT scan was requested, revealing hypodense bilateral hemispheric subdural collections, suggestive of chronic subdural haematomas. He was submitted to surgical drainage by burr holes, which confirmed the chronic subdural collection on the left side. Unexpectedly, after dural opening on the right side, a subdural purulent collection was found, which was later confirmed as an empyema due to Escherichia coli infection. A second surgical drainage was performed by craniotomy due to recurrence of the right subdural collection. Spontaneously appearing subdural empyemas due to E. coli are extremely rare and their treatment is not always straightforward. The reported case is an example of an apparently straightforward and frequent pathology that turned out to be a challenging case, requiring a multidisciplinary approach.