Subarachnoid Hemorrhage due to Cerebral Cavernous Malformation in a Young Female

Cerebral cavernous malformations (CCMs) are usually intraparenchymal lesions commonly associated with intraparenchymal hemorrhage. Extra-axial Lesions are uncommon and have rarely been reported as the cause of aneurysmal like subarachnoid hemorrhage (SAH). We present a 33-years-old female with a past medical history significant for hypertension who presented with acute onset head and neck pain after bending over. En route to the hospital, she had abnormal motor movements suggestive of seizures. Computed tomography (CT) of the head was significant for diffuse aneurysmal like SAH. Head CT angiography (CTA) and catheter digital subtraction angiography (DSA) were both negative for aneurysm. Magnetic resonance imaging (MRI) of the brain showed susceptibility artifact in the right parafalcine frontal lobe suspicious for underlying CCM. This lesion was in the area suspected of having an aneurysm on CT head. The patient was diagnosed with SAH secondary to cavernous malformation mimicking aneurysmal etiology. This case is important as it serves as a good reminder to consider cavernous malformations in the differential in patients presenting with angiogram negative SAH. Diagnosis of this entity has treatment implications including discontinuation of calcium channel blockers if initiated, discussion about duration of anti-seizure medication, in addition to consideration for surgical intervention in select populations.