Early development and rupture of de novo aneurysm--case report.

A 38-year-old non-smoker man presented with a ruptured aneurysm one month after clipping of a previous aneurysm. He was first admitted because of sudden onset of severe headache. Brain computed tomography showed subarachnoid hemorrhage. Angiography showed an aneurysm of the left anterior choroidal artery which was surgically clipped. Two weeks later, he was discharged without neurological deficits. One month after the initial hemorrhage, he was readmitted to the emergency room with stuporous mentality. Repeat angiography showed two aneurysms of the A2 portion of the left anterior cerebral artery which were not demonstrated by the initial angiography. The diagnosis was de novo aneurysms. The larger aneurysm was clipped and the other was coated. De novo aneurysm should be suspected if a patient with a previously clipped aneurysm complains of typical headache or any suggestive symptoms or signs of cranial nerve dysfunction, especially if known risk factors are present.