Differences in circadian variation of cerebral infarction, intracerebral haemorrhage and subarachnoid haemorrhage by situation at onset.

BACKGROUND: The precise time of stroke onset during sleep is difficult to specify, but this has a considerable influence on circadian variations of stroke onset. AIM: To investigate circadian variations in situations at stroke onset--that is, in the waking state or during sleep--and their differences among subtypes. METHODS: 12,957 cases of first-ever stroke onset diagnosed from the Iwate Stroke Registry between 1991 and 1996 by computed tomography or magnetic resonance imaging were analysed. Circadian variations were compared using onset number in 2-h periods with relative risk for the expected number of the average of 12 2-h intervals in the waking state or during sleep in cerebral infarction (CIF), intracerebral haemorrhage (ICH) and subarachnoid haemorrhage (SAH). RESULTS: ICH and SAH showed bimodal circadian variations and CIF had a single peak in all situations at onset, whereas all three subtypes showed bimodal circadian variations of stroke onset in the waking state only. These variations were different in that CIF showed a bimodal pattern with a higher peak in the morning and a lower peak in the afternoon, whereas ICH and SAH had the same bimodal pattern with lower and higher peaks in the morning and afternoon, respectively. CONCLUSIONS: Sleep or status in sleep tends to promote ischaemic stroke and suppress haemorrhagic stroke. Some triggers or factors that promote ischaemic stroke and prevent haemorrhagic stroke in the morning cause different variations in the waking state between ischaemic and haemorrhagic stroke.

[Fenestrated basilar artery aneurysm: case report].

The authors reported an operated case with an aneurysm arising from the proximal end of basilar artery fenestration, and discussed its etiology and surgical strategy. A 47-year-old woman presented with slight memory disturbance. Neuroradiologic examination revealed an aneurysm located on the proximal end of the basilar artery 12 x 9 mm in size at the level of the outer auditory meatus. The union of vertebral arteries had deviated toward the right side, and the aneurysmal dome had projected into the fenestration. Through the right far lateral approach, we applied two straight fenestrated clips X configuration to the aneurysm. Several authors have reported a variety of approaches for vertebrobasilar aneurysms along the midline with consideration of the height of the aneurysmal. However, another point of view is that attention should be paid to the direction of the clip blade and applied at the final clipping, because, for vertebrobasilar aneurysms adjacent to the midline, the surgical view and working space are extremely restricted.

[Multiple dural arteriovenous shunts presenting as subarachnoid hemorrhage: a case report].

We present here an interesting case of multiple dural arteriovenous shunts (dAVS) in different locations at the same time. There have been very few reports on multiple dAVS. A 63-year-old man was admitted with a sudden onset of headache and vomiting. CT scan showed a typical subarachnoid hemorrhage (Fisher Group 3). Cerebral angiogram (6 vessel study) revealed two dural arteriovenous shunts at the same time. One was located on the anterior fossa fed by the anterior ethmoidal artery, and the other was located on the posterior fossa near the marginal sinus fed by the left ascending pharyngeal and occipital arteries. At first, transarterial embolization was performed for dAVS located on the posterior fossa. Radical operation was performed for both anterior and posterior fossa dAVS. Both dAVS had disappeared on postoperative angiograms.

[An acute epidural hematoma soon after nose blowing: a case report].

We reported a very rare case of an epidural hematoma soon after nose blowing. A 22-year-old male visited our hospital complaining of severe headache and nausea soon after he blew his nose. Thirteen years ago, he had a ventriculo-peritoneal (V-P) shunt operation for a pineal region tumor which had not recurred after irradiation. His left auditory tube had been patent. He hit his head about 3 months ago. On his arrival, his consciousness was almost clear but we observed slight right hemiparesis. Computed tomography of his head obtained on the first day showed the air in the hematoma in the left parietal epidural space which penetrated his petrosal bone from the mastoid air cells. Removal of his epidural hematoma was performed the next day and there was no abnormality of his parietal bone, dura and meningeal arteries. We supposed that nose blowing was what triggered his epidural hematoma. From pressure of nose blowing, the air of his nasopharyngeal space passed through his patent auditory tube into the tympanic cavity, and entered into the epidural space penetrating a microfracture or dissociation in the petrosal bone. In addition to this, V-P shunt system and the looser adhesion of dura to the skull in the young promoted entrance of air. Associated with formation of epidural hematoma in this case were four factors, "patency of auditory tube", "defect or microfracture of petrosal bone", "V-P shunt", "younger age" and triggered by nose blowing.