STROKE

SEASONAL VARIATION IN ETIOLOGY

Abstract

Objective: To document seasonal variations in
various types of stroke and to identify possible precipitating/aggravating factors. Design: Analytical. Place and
Duration of Study: Military Hospital Rawalpindi and Combined Military Hospital Rawalpindi, for one year, from Ist
October 2001 to 30th September 2002. Patients and Methods: 116 adult stroke patients diagnosed on the basis of
history, clinical examination and CT Scan and admitted during this period were included in the study. The findings were
documented and analyzed using SPSS and frequency of stroke in relation to seasons was calculated. Chi square test
was used to determine significance of differences in frequency of different types of stroke in the winter and summer.
Results: The age of the patients ranged from 20-87 years.83 were males while 33 were females. Sixty-nine out of 116
cases presented in summer and the rest 47 in winter. In summer out of 69 subjects, 48(69.56%) had ischaemic strokes
and 21(30.44%) had hemorrhagic strokes, of which 19 had Intra Cerebral Hemorrhage (ICH) and 2 subarachnoid
hemorrhage (SAH). In winter, out of 47 subjects, 28(59.57%) had ischaemic strokes and 19(40.43%) had haemorrhagic
strokes (all ICH). Two definite seasonal peaks one in extreme summer (June, July) and the other in extreme winter
(December, January) were seen. Conclusions: There is a significant variation in frequency of stroke and its different
types in different seasons of the year with higher occurrence in peak summer (June, July) and extreme winter
(December, January).