Bilateral acute subdural hematomas with intracerebral hemorrhage without subarachnoid hemorrhage, caused by rupture of an internal carotid artery dorsal wall aneurysm. Case report.

A 45-year-old man presented with bilateral acute subdural hematomas (ASDHs) without subarachnoid hemorrhage (SAH). He was found comatose in a parked car. Computed tomography showed left frontal intracerebral hemorrhage (ICH) and bilateral ASDHs but no signs of SAH. Magnetic resonance angiography demonstrated an internal carotid artery dorsal wall aneurysm. Emergent surgical intervention was performed. However, he died of cerebral herniation 6 days later. We inferred that massive intracranial bleeding might have ruptured through the cortex and lacerated the arachnoid membrane. Aneurysm rupture generally results in unilateral SDH, whereas trauma is the usual cause of bilateral ASDHs with ICH. Our case suggests that ruptured aneurysm should be considered in patients with non-traumatic bilateral ASDHs without SAH.