Acute subdural and subgaleal empyema.

A case is presented in which the initial CT scan failed to demonstrate subdural suppuration over both convexities. Definitive CT finding of subdural empyema (SDE) was only positive at an advanced stage, when a bilateral subgaleal empyema also spread out. Because of the fulminant development of the subdural empyema and the delayed diagnosis, the outcome was fatal in spite of neurosurgical operation. Subdural empyema is a neurological and neurosurgical emergency. Early diagnosis is imperative, because the mortality is about 25-40% and the outcome depends upon the promptness of diagnosis and the appropriate operation. In the recent literature the value of computerised tomography for early detection of subdural empyema is controversial. Some reports failed to demonstrate any evidence of purulent subdural collection in CT scans while others were able to make an early diagnosis. This report presents a case which demonstrates the difficulties in making an early diagnosis of a subdural empyema by CT.