1145. Monsoon Rain and Rupture of Cerebral Aneurysms in Sri Lanka

Authors: Charith Ishan Janendra Nanayakkara, MBBS, MD, MRCS; Nishantha Gunasekera; Nadun Mohotti (Galle, Sri Lanka)


The seasonal variation of cerebral aneurysm rupture is a a well described occurrence in western literature. The seasons in the Asian tropics is somewhat different from the typical four seasons that we encounter in the west.


A retrospective analytical study was conducted on the ruptured cerebral aneurysms that were operated at Teaching Hospital Karapitiya, Galle, Sri Lanka using the theatre database for a time period of five years. Aneurysms (n=61) were analysed based on the Time of the year which was clustered into Tertiles which resembled the seasons in SriLanka based on the Monsoon rain. Average rainfall and temperature of Sri Lanka in different months was also calculated and correlated from online resources of the department of Meteorology.


Out of 61 patients, 33 were male (54.1%) and 28 female (45.9%). ACOM aneurysms were by far the commonest type (68.8%). The average age is 54 with the age range from 24 to 78. Statistical analysis of the rate of aneurysm rupture at each tertile gave a Chi square value of 6.50 which indicated that the probability of this occurrence is statistically significant at a p value of 0.05. The rupture rate appears to have an association with the average rainfall. The average rainfall in each Tertile was different but was not statistically significant even though classified as different monsoon seasons in SriLanka.


There is a statistically significant difference between the rupture rate of cerebral aneurysms depending on the time of the year. This appears to have some correlation with the seasons in Sri Lanka which is related to the rainfall and the monsoons but the exact climate variable (Average temperature, fluctuation of temperature, average rainfall) could not be statistically established.