THE CLINICAL SPECTRUM OF UNRUPTURED INTRACRANIAL ANEURYSMS

Objective.-A retrospective study was performed to delineate the clinical characteristics of symptomatic unruptured aneurysms. Design.-Patient histories, operative reports, and angiograms in 111 patients with 132 unruptured aneurysms were reviewed. Setting.-Tertiary care university hospital. Patients.-One hundred eleven patients with 132 unruptured intracranial aneurysms were studied. There were 85 women and 26 men, with a mean age of 51.2 years (age range, 11 to 77 years). Many patients were referred by community neurologists and neurosurgeons for further evaluation and neurosurgical management. Results.-Fifty-four symptomatic patients were identified. Group 1 (n=19; mean aneurysm diameter, 2.1 cm) had acute symptoms: ischemia (n=7), headache (n=7), seizure (n=3), and cranial neuropathy (n=2). Group 2 (n=35; mean aneurysm diameter, 2.2 cm) had chronic symptoms attributed to mass effect: headache (n=18), visual loss (n=10), pyramidal tract dysfunction (n=4), and facial pain (n=3). Group 3 (n=57; mean aneurysm diameter, 1.1 cm) had asymptomatic aneurysms. Conclusions.-Acute severe headache, comparable to subarachnoid hemorrhage headache, but without nuchal rigidity, was associated with the following mechanisms: aneurysm thrombosis, localized meningeal inflammation, and unexplained. Unruptured aneurysms may be misdiagnosed as optic neuritis or migraine, or serve as a nidus for cerebral thromboembolic events. Internal carotid artery and posterior circulation aneurysms were more likely to cause focal symptoms from mass effect than were anterior cerebral artery and middle cerebral artery aneurysms. Weeks to years may elapse before their diagnosis. The absence of subarachnoid blood does not exclude an aneurysm as a cause for acute or chronic neurologic symptoms.