Prognostic value of intraventricular blood in perimesencephalic nonaneurysmal subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH) is a distinct type of subarachnoid hemorrhage with a characteristic bleeding pattern, and an excellent clinical outcome. However, the clinical course of patients presenting with a perimesencephalic nonaneurysmal bleeding pattern and intraventricular blood has not yet been investigated.

In this retrospective study we describe the cisternal blood distribution and the clinical course of 34 PNSH patients with (10 patients) and without (24 patients) intraventricular blood.

Patients without intraventricular blood were in good clinical condition on admission; the in-hospital course was uneventful except for acute hydrocephalus, which was detected in two cases and improved spontaneously in both patients. All patients resumed their previous lifestyles. In contrast, two patients with PNSH and intraventricular blood were drowsy and had focal neurologic deficits on admission. Four patients developed an acute hydrocephalus, and two of these patients needed ventricular shunting. There was evidence for delayed cerebral ischemia in one of these patients. Outcome was excellent in eight cases, and one patient was moderately and one patient was severely disabled at dismissal from the hospital. Rebleeding did not occur in all patients, and repeated four-vessel angiography did not reveal the source of bleeding in any of our patients.

Our data indicate that the presence of intraventricular blood may be a good indicator for the development of acute hydrocephalus in PNSH. Moreover, our results suggest that PNSH patients with ventricular blood may have a higher complication rate and a poorer outcome compared with PNSH patients without intraventricular blood.