The warning leak in subarachnoid hemorrhage and the importance of its early diagnosis.

A 40-year-old man had a severe headache of sudden onset and progressive palsy of the third cranial nerve from a minor subarachnoid hemorrhage. Despite assessment by two primary care physicians the possibility of serious neurologic disease was not raised and the urgency of the situation not appreciated. Two weeks after the onset of the headache the patient was urgently admitted to hospital at the request of a neuro-ophthalmologist. Cerebral angiography revealed an aneurysm of the posterior communicating artery, which was surgically occluded with a clip. The patient had a satisfactory recovery, with almost complete return of nerve function by the time of discharge from hospital. Such "warning leaks" in subarachnoid hemorrhage are discussed, and a protocol for their assessment is recommended.