Delayed intraventricular tension pneumocephalus complicating posterior fossa surgery for cerebellar medulloblastoma.

A child is described in whom intraventricular tension pneumocephalus developed 10 days after removal of a cerebellar medulloblastoma and 1 day after suture removal. The tension pneumocephalus was associated with hydrocephalus and CSF leakage from the suture line. The symptoms of the pneumocephalus were rapidly progressing loss of consciousness and hemiplegia which were promptly reversed upon aspiration of the intracranial air. A large amount of intraventricular air present in the immediate postoperative period was, however, clinically silent. The characteristics of this unusual presentation, its relation to asymptomatic pneumocephalus, hydrocephalus and the preventive and therapeutic measures required to deal with such conditions are discussed.