596 Lee et al. Fatal Subarachnoid Hemorrhage from the Rupture of a Totally Intracavernous Carotid Artery Aneurysm: Case Report Andrew G. Lee, M.D., Michael E. Mawad, M.D., David S. Baskin, M.D. Departments of Ophthalmology, Neurology, and Neurosurgery (AGL), the Department of Neuro-radiology (MEM), and the Departments of Neurosurgery and Anesthesiology (DSB), Baylor College of Medicine, Houston, Texas INTRACAVERNOUS CAROTID ARTERY aneurysms usually cause symptoms because of gradual expansion without rupture. Most such aneurysms that do rupture lead to a carotid-cavernous fistula. Very few cases of rupture leading to subarachnoid hemorrhage have been reported. We report a case in which rupture of an entirely intracavernous carotid artery aneurysm led to death from a massive subarachnoid hemorrhage. (Neurosurgery 38:596-599, 1996) Key words: Aneurysm, Carotid artery, Intracavernous, Rupture T he rupture of aneurysms involving the intracavernous portion of the in- ternal carotid artery is uncommon (1-8). Most such aneurysms that do rupture de- velop a carotid-cavernous fistula because of the support of the dura of the cavern- ous sinus. Subarachnoid hemorrhage is a rarely reported life-threatening complica - tion of these aneurysms (1-6). We report a case of the lethal rupture of an entirely intracavernous carotid artery aneurysm. CASE REPORT A 72-year-old white woman pre- sented with acute binocular vertical dip- lopia and severe headache. Her medical history was significant for degenerative joint disease, fibrocystic breast disease, and removal of a benign parotid gland nodule in childhood. She was not taking any medications on a regular basis. She presented on February 4, 1995, to her regular physician with the acute onset of a severe frontal headache. Two days later, she developed a partial ptosis of the left upper lid and acute binocular diplopia. She was subsequently referred to our institution on February 6, 1995. A neuro-ophthalmological examination at that time revealed normal visual acuity of 20/20 in each eye. The right pupil measured 4 mm and reacted normally to light, and the left pupil measured 6 mm and reacted poorly to light. There was no afferent pupillary defect present. Visual field testing revealed nothing ab- normal in either eye. A motility exami- nation revealed a left partial 111rd nerve palsy with moderate limitation of ad- duction, elevation, and depression of the left eye. There was intorsion of the globe in downgaze in the left eye, sug- gesting an intact left IVth nerve. Abduc- tion of the left eye was normal, and the right eye moved normally in all direc- tions of gaze. Ophthalmoscopy revealed a normal optic nerve and fundus in each eye. There was diminished sensation in the cutaneous distribution of the oph- thalmic division of the trigeminal nerve on the left. The remainder of the neuro- logical examination revealed nothing abnormal. The patient was admitted to the hos- pital. A cerebral magnetic resonance (MR) scan (Fig. 1, A and B) and MR angiography (Fig. 2) revealed a left- sided intracavernous internal carotidar tery aneurysm. On February 7 ,1995 the patient experienced worsening of her pain and developed a complete left- sided ophthalmoplegia. Cerebral an- giography confirmed a large left-sided totally intracavernous internal carotid artery aneurysm (Fig. 3). There was ( small collection of contrast material al the origin of the right posterior cerebra artery from the tip of the basilar arten which was suggestive of a small sessile aneurysm in this location. No other ce- rebral aneurysms were detected. Anen- dovascular balloon test occlusion of the internal carotid artery was performai for 30 minutes at the time of cerebral angiography. Continuous electroen- cephalographic tracing, as well as speech, mental status, and motor func- tion monitoring, were performed dur- ing the test occlusion. JB The patient tolerated the occlusion without the development of new neuro- logical signs or svmptoms or abnormal ities on the electroencephalographic tracing. Technetium-99 cerebral perfu - sion single photon emission computec tomography (SPECT) was performed to further assess the risk of cerebral isch- emia after permanent internal carotin artery occlusion. Permanent occlusion was deferred in this patient until after the results of the SPECT could be ana- lyzed. Patients with evidence of cerebral ischemia, as revealed by SPECT are considered candidates for possible ex- ternal carotid artery to internal carotid » 1 artery bypass graft before permanent in- ternal carotid artery occlusion to dim in- ish the risk of ischemic stroke. In tto- patient, SPECT showed decreased acth ity in the left temporal and left parieta. lobes after the balloon occlusion test- The patient was scheduled for comply permanent occlusion of the carotid t tery by endovascular technique the no morning, pending the results of SI t On the evenine of February 8,1995, the patient became acutely obtunded ^1 fixed and dilated pupil on the rlC side. She suffered a cardiac arrest, eon not be resuscitated, and died. A eon plete postmortem examination Neurosurgery , Vol. 38 , No. 3, March 19 96