Seasonal and diurnal Variations of Predisposing Factors to Cerebral Aneurysm Rupture

Yim, Man Bin; Lee, Jang Chull; Son, Eun Ik; Kim, Dong Won; Kim, In Hong

Abstract

In order to determine the predisposing factors to cerebral aneurysm rupture and to examine the relationship between circadian periodicity of blood pressure change and the rupture of an aneurysm, the authors investigated activities of the patients of events as well as diurnal and seasonal variations in the onset of subarachnoid hemorrhage (SAH) in 766 consecutive patients. The authors also compared the difference of these data between patients with a history of hypertension and patients without a history of hypertension. The results showed that the onset of SAH was associated with defecation and/or urination in 12.3%, working on the jab in 11.8%, housework including washing clothes in 10.3%, sleeping in 7.4% and bathing and/or washing up in 7.2%. The incidence of the onset of SAH associated with defecation an/or urination was higher in patients with a history of hypertension than in patients without a history of hypertension(p<0.05). The diurnal variation of the onset of SAH showed two broad peak times from 6 to 10 a.m.(21.8%) and from 5 to 8 p.m.(18.3%). The seasonal variation of the onset of SAH showed the incidence to be slightly higher in winter than in any other seasons autumn and winter, the leading activities of the patients or events in the onset of SAH was defecation and/or urination and, in summer, it was job performing. We concluded that the onset of the SAH is related not only to the physiological circadian periodicity of blood pressure change but also to the activities or events which induced a sharp rising blood pressure and changing the venous and cerebrospinal fluid pressure.