Simultaneous subdural effusion and hydrocephalus in infancy.

Hydrocephalus and subdural hematoma or effusion of infancy rarely present simultaneously, where both are active contributors to acutely increased intracranial pressure. In three cases, clinical findings characteristic of both were present. Decompression of one can facilitate expansion of the other. Rapid progression of unsuspected hydrocephalus could be responsible for some of the poor results reported after treatment of subdural effusion alone. This possibility should be considered whenever progress is unsatisfactory during treatment of subdural effusion.