Adult aqueductal stenosis presenting as a thunderclap headache: a case report.

[hydrocephalus with stenosis of the aqueduct of sylvius]

Thunderclap headache is well known to be a presenting feature of a variety of causal events . Indeed , a primary form is considered in the International Classification of Headache Disorders-II , but such diagnosis must be made only after exclusion of a possible secondary cause . We report a case of late-onset idiopathic aqueductal stenosis presenting with thunderclap headache , in the absence of abnormal neurological findings or indirect signs of raised intracranial pressure . The patient recovered completely after endoscopic third ventriculostomy . This case indicates primary aqueduct stenosis as a possible , never previously reported , cause of thunderclap headache .