PRETRUNCAL NONANEURYSMAL SUBARACHNOID HEMORRHAGE

Objective: To review the diagnostic evaluation and the clinical course of patients with pretruncal nonaneurysmal subarachnoid hemorrhage, Ma terial and Methods: The study population consisted of a consecutive se ries of patients with a pretruncal nonaneurysmal subarachnoid hemorrha ge encountered at Mayo Clinic Rochester during a 6-year interval. We r eviewed the clinical manifestations, the neuroimaging characteristics, and the appropriate management. Results: The 15 male and 9 female pat ients with a pretruncal nonaneurysmal subarachnoid hemorrhage ranged f rom 3 to 72 years of age (median, 45). Of the 24 patients, 18 had a su dden explosive headache at the time of initial assessment. Ventricular shunting for acute hydrocephalus was indicated in one patient, Neuroi maging studies demonstrated that the center of the hemorrhage was prep ontine, and it extended into the interpeduncular or premedullary ciste rns. In two patients, a small focal hemorrhage was not noted on an adm ission computed tomographic scan but was identified on repeated study. A second four-vessel cerebral angiogram, obtained in most patients, s howed normal findings in four patients who had had cerebral vasospasm on the first study. In one patient, moderate cerebral vasospasm was fo und on the second angiogram, No patient had rebleeding, One patient ha d transient dysphasia associated with cerebral vasospasm after cerebra l angiography, Two patients had a family history of aneurysmal subarac hnoid hemorrhage, Conclusion: The excellent outcome in patients with p retruncal nonaneurysmal subarachnoid hemorrhage is in distinct contras t to the overall somber outcome associated with aneurysmal subarachnoi d hemorrhage. A ruptured aneurysm of the posterior circulation may mim ic a pretruncal nonaneurysmal subarachnoid hemorrhage and should be ex cluded on the basis of a technically satisfactory cerebral angiogram.