An Acute Subdural Hemorrhage Due to a Left Supraclinoid Internal Carotid Artery Aneurysm Rupture Without a Subarachnoid Hemorrhage.

Acute subdural hemorrhage (SDH) is a rare complication that can occur after a spontaneous intracranial aneurysmal rupture. It is commonly associated with a subarachnoid and/or an intracerebral hemorrhage but rarely occurs as an SDH alone. A 52-year-old female presented to our institution with a severe headache and third cranial nerve palsy. A computed tomography (CT) scan revealed acute left SDH, without a subarachnoid hemorrhage (SAH), and a computed tomography angiogram (CTA) and cerebral angiography demonstrated the presence of a left supraclinoid aneurysm pointing towards the cavernous sinus. Endovascular occlusion of the aneurysm was performed using a flow diverter. A follow-up CT scan revealed a resolved SDH. In similar situations, vascular imaging, such as CTA and cerebral angiography, is required to assess the cerebral vasculature. This case report describes a patient presenting with the sudden onset of a severe headache associated with a cranial nerve palsy and a brain CT scan showing an acute SDH in the absence of trauma or an anticoagulation history. The treating physician should be highly vigilant of the possibility of a ruptured intracranial aneurysm as the underlying SDH etiology.