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[Necessity of cerebral angiography in thunderclap headache patients who show no evidence of subarachnoid hemorrhage: investigation of 350 cases].

PURPOSE
The necessity of cerebral angiography was assessed in patients with thunderclap headache in whom subarachnoid hemorrhage had been ruled out on CT findings and the color of cerebrospinal fluid (CSF).


SUBJECTS AND METHODS
The subjects of this study were 350 patients with thunderclap headache in whom subarachnoid hemorrhage was ruled out at our clinic based on CT findings and the color of CSF. The time span from the onset of thunderclap headache to the first visit to our clinic ranged from 1 to 9 days (mean: 2.5 days). The ages of the patients ranged from 22 to 64 years. 147 were male and 203 female. All patients underwent CT angiography. Percutaneous cerebral angiography was also performed in cases in which cerebral aneurysms were suspected on CT angiography or the CSF cell count was elevated (over 10/3mm3 on white blood cells).


RESULTS
(1) Of the 350 patients, 162 were suspected to have cerebral aneurysms when examined by CT angiography. When these 162 patients were examined by percutaneous cerebral angiography, cerebral aneurysms were found in 34 patients (9.7%). (2) Four patients had an elevated CSF cell count. Cerebral aneurysms were found in all these patients. (3) Of the 34 patients with cerebral aneurysms, 31 consented to and underwent direct surgery. Localized subarachnoid hemorrhage around their aneurysms was found in seven (22.6%) of these 31 patients intraoperatively. Elevation in CSF cell count was shown in three of these patients.


CONCLUSION
Even when CT and CSF studies reveal no abnormalities in the early stage after the onset of thunderclap headache, subarachnoid hemorrhage can not be ruled out. Therefore, cerebral angiography is recommended in patients with thunderclap headache.