Rupture of a previously documented small asymptomatic intracranial aneurysm in a patient with autosomal dominant polycystic kidney disease. Case report.

Intracranial aneurysms are common extrarenal manifestations of autosomal dominant polycystic kidney disease (ADPKD). Although their natural history is not completely understood, small asymptomatic intracranial aneurysms in patients with ADPKD often are not treated but are followed with serial magnetic resonance (MR) angiography. The authors report the unique case of a patient with ADPKD who bled from a previously documented asymptomatic 3-mm intracranial aneurysm. This 42-year-old man with ADPKD suffered a subarachnoid hemorrhage (SAH) from a 7-mm left pericallosal artery aneurysm. This aneurysm was clipped and the patient made an excellent recovery. An irregular asymptomatic 3-mm right middle cerebral artery (MCA) aneurysm had also been demonstrated on angiography. While the patient was considering elective surgery for the MCA aneurysm, he suffered a hemorrhage from this lesion 10 weeks after the initial SAH. The aneurysm was clipped and the patient made a satisfactory recovery (he was moderately disabled). In this report the authors indicate that small asymptomatic intracranial aneurysms are not always innocuous in patients with ADPKD, and they suggest that treatment should be strongly considered for these lesions in this group of patients when there is a history of SAH or the aneurysm is irregular in appearance. Because MR angiography studies may not adequately define the configuration of small aneurysms and irregularity may easily be missed, conventional angiography is recommended for patients with ADPKD who are found to have an intracranial aneurysm on screening with MR angiography.