[The relationship between the rupturing of intracranial aneurysm and season, weather and patient's acitivity (author's transl)].

Some physical and mental stresses have been notices as the exciting factors for the occurrence of cerebrovascular diseases. However, little has been known about them of ruptured intracranial aneurysms. From this point of view, the correlation between the several physical strains and the occurrence of ruptured intracranial aneurysm were studied in this report. This study was based on 920 cases of ruptured intracranial saccular aneurysm which were verified by direct aneurysmal surgery. As for the season, the occurrence of ruptured intracranial aneurysms was apt to be frequent in winter and infrequent in summer. No relation between the onsets and the meteorological fronts could be found. The incidence during sleep was about 6%. This incidence was thought to be rather lower considering the fact that one-third of our lives is spent in sleep. Lifting and bending, defecation and/or urination and emotional strain were among the commonest environmental events associated with the onset. Based on these results, wheather or season, which is mild physical stress, can in no way be considered a great cause of rupturing of intracranial aneurysm, but it should seen that patient's activities or events have some influences in rupturing of aneurysm to a great extent.