Acute subdural hematoma caused by an unruptured, thrombosed giant intracavernous aneurysm.

Introduction: Acute subdural hematoma (SDH) is an infrequent complication after aneurysmal subarachnoid hemorrhage. SDH associated with unruputed intracavernous aneurysm has never been reported.

Methods: Single patient case report and review of relevent literature.

Results: A 65-year-old woman with an unruptured, thrombosed giant intracavernous aneurysm developed an acute SDH 2 days after admission for cavernous sinus syndrome. Despite emergent evacuation of the SDH, the patient never regained consciousness because of brain herniation.

Conclusion: Acute SDH is a rare complication of ruptured, giant intracavernous aneurysms. Erosion of the cavernous sinus wall by acute enlargement of the aneurysm after thrombosis is the proposed mechanism for development of the SDH.