Pretruncal nonaneurysmal subarachnoid hemorrhage causing basilar artery vasospasm.
BACKGROUND
Pretruncal nonaneurysmal subarachnoid hemorrhage (PNSAH), more commonly known as perimesencephalic nonaneurysmal subarachnoid hemorrhage, is characterized by the presence of subarachnoid hemorrhage anterior to the midbrain with no evidence of an intracranial aneurysm on four vessel craniocervical angiogram. Although vasospasm is a common occurrence after aneurysmal subarachnoid hemorrhage and can lead to significant morbidity and mortality, vasospasm in the setting of PNSAH is rare.


METHODS
The purpose of this report is to describe the case of a patient with PNSAH who developed significant radiographic vasospasm of the basilar artery that altered clinical management. The current literature on this uncommon disease entity and management considerations are discussed.


RESULTS
A four-vessel cerebral angiogram was performed on hospital day (HD) two that did not demonstrate any apparent vascular abnormality or vasospasm. A repeat craniocervical angiogram on HD 8 demonstrated significant stenosis of the basilar artery consistent with vasospasm. The patient continued to be neurologically intact. A repeat cerebral angiogram performed on HD 15 demonstrated resolving vasospasm. There continued to be no evidence of a source of his initial hemorrhage.


CONCLUSIONS
PNSAH is associated with an excellent clinical course that is rarely associated with long-term sequelae. Although cerebral vasospasm rarely develops radiographically or clinically in patients with PNSAH, evidence suggests that clinical observation comparable to that performed in patients with aneurysmal SAH should be performed until a second confirmatory study has conclusively ruled out an aneurysmal source and until clinical and radiographic evidence of resolution of severe vasospasm is obtained.
Hsu
Wesley
W
Department of Neurosurgery, The Johns Hopkins University School of Medicine, Johns Hopkins Medical Institutions, Meyer Bldg. 8-161, 600 N. Wolfe St., Baltimore, MD 21287, USA. weshsu@jhmi.edu
Pradilla
Gustavo
G
Garonzik
Ira M
IM
Conway
James E
JE
D001342:Autonomic Nervous System Diseases / Q000000981:diagnostic imaging / Q000209:etiology; D001488:Basilar Artery / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D006801:Humans; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D014057:Tomography, X-Ray Computed; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging* / Q000209:etiology; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging*