Traumatic basal subarachnoid hemorrhage suspected to have been caused by contrecoup cerebellar contusions: a case report.

Traumatic cerebellar hemorrhagic contusions are infrequent, and the pathogenic mechanism involves a coup injury that is associated with motor vehicle accidents in most cases. Traumatic basal subarachnoid hemorrhage (TBSAH) is commonly reported after blunt trauma to the neck or unrestricted movement of the head, and the source of the hemorrhage is most frequently identified in the vertebrobasilar arteries. A 55-year-old woman who was addicted to alcohol was found dead in her bed. She had a bruise on the left side of her posterior parietal region, and autopsy revealed massive subarachnoid hemorrhage at the base of the brain; the hematoma was strongly attached to the right lower surface of the cerebellar hemisphere. No ruptured cerebral aneurysms, arteriovenous malformations or vertebrobasilar artery leakage were detected. Hemorrhagic cerebellar contusions were regarded as the source of the TBSAH. This is the first report of TBSAH suspected to have been caused by contrecoup cerebellar contusions.