[Subarachnoid hemorrhage caused by a dissecting carotid artery aneurysm]

Dissecting aneurysms of the carotid artery as a cause of subarachnoid hemorrhage are rare. However, the association of arterial dissection with the etiology of some aneurysms of the dorsal or anterior wall of the carotid artery, carotid trunk or "blister-like" aneurysms has increased the interest in the description of dissecting aneurysms, as they are difficult to treat and require non-habitual surgical techniques. We present the case of a patient that presented with a poor grade subarachnoid hemorrhage secondary to a right carotid artery dissecting aneurysm characterised in angiography by a carotid artery stenosis accompanied by a post-stenotic dilatation and the finding of a saccular aneurysm that increased in size in the follow-up study. A carotid occlusion test showed an asymmetry in the opacification of the venous phase indicating the need for a revascularization procedure prior to arterial sacrifice. A high flow EC-IC bypass was performed using a saphenous vein graft prior to right carotid artery occlusion without morbidity. Eight months after the procedure the patient is free of neurological deficit. Control image studies demonstrate the resolution of the carotid lesion and the bypass permeability. We discuss the difficulties in the diagnosis of these aneurysms, their clinical and imaging characteristics and the problems related to their treatment as they often require arterial sacrifice with or without prior cerebral revascularization.