Head injury unmasking other brain diseases.

Sixteen patients previously free of neurological complaints sustained minor head injuries and subsequently presented acutely with a wide range of unexpected, serious brain diseases. These included brain tumours, berry aneurysms, arteriovenous malformations and brain abscess. The possible, responsible mechanisms include direct mechanical trauma to the asymptomatic brain lesion, hydrocephalus and brain oedema. This unusual complication of head injury should be suspected when a florid neurological syndrome follows a minor head injury. CAT scanning usually identifies the responsible disease. Because of its therapeutic implications, this complication deserves recognition in the differential diagnosis and management of head injuries.