Intracranial hemorrhage produced by spontaneous dissecting intracranial aneurysm.

Two patients with intracranial dissecting aneurysms were seen initially because of acute hemorrhage. One patient died, and a false dissecting aneurysm secondary to atherosclerosis was found at autopsy. In the other patient, the appearance of the carotid arteriogram was typical of a dissection. Because of the propensity of these aneurysms to rupture, caution is indicated in the use of anticoagulants or vasopressors in patients with evolving cerebral infarction secondary to intracranial arterial dissection.