[A case of delayed subrachnoid hemorrhage from vertebrobasilar artery dissecting aneurysm].

We report a case of delayed subarachnoid hemorrhage (SAH) from a vertebrobasilar artery dissecting aneurysm (VBA-DA). The patient was a healthy 32-year-old woman with a sudden onset of severe occipitalgia. Next day, her headache improved gradually, and she consulted with our department. Although we initially suspected that she was suffering from SAH, neurological findings, CT, and cerebrospinal fluid examination did not reveal any abnormal conditions, including SAH. Therefore, she was treated conservatively with analgesics. Twelve days after the initial onset of the headache, she was admitted because of severe re-attack of headache, rt. hemiparesis with rt. oculomotor nerve palsy and loss of consciousness. CT revealed moderate SAH and cerebral angiograms showed VBA-DA. After the cerebral angiography, bleeding reoccurred two times and she lost her life. We present the case, review the literature and discuss the relationship between presenting symptom of headache and non-hemorrhagic VBA-DA. A few cases of non-hemorrhagic VBA-DA have been reported in the literature in which the only presenting symptom was headache, followed by delayed SAH from non-hemorrhagic dissecting aneurysm. Consequently, we concluded that her initial symptom of headache was due to dissection of vertebrobasilar artery, and that SAH was due to delayed hemorrhage of non-hemorrhagic VBA-DA. Even when neurological findings, CT and cerebrospinal fluid examination reveal no abnormalities in the early stage after the sudden onset of headache, especially in the occiptal or nuchal regions, non-hemorrhagic VBA-DA, which has a risk of fatal hemorrhage, cannot be ruled out with certainty. Therefore, MRI, MRA, three-dimensional CT, or cerebral angiography should be performed in such cases.