International Journal of Collaborative Research on Internal Medicine & Public Health

A study of anatomical, seasonal and diurnal variation in the occurrence of ischemic stroke

Introduction: Stroke is the third largest cause of mortality in India after heart attack and cancer. The stroke mortality rates are declining or stabilising in developed countries but there is concern over the emerging epidemic of stroke in India. Study of topographical distribution, seasonal and temporal variations in occurrence of ischemic stroke provides insight into factors that trigger onset of stroke which might lead to more rational treatment.

Objective: To assess and categorize anatomical distribution of ischemic strokes, seasonal and diurnal variations in occurrence of stroke.

Method: A retrospective analysis of MRI data of patients of Jabalpur Diagnostic Center, Jabalpur M.P. India who were enrolled during 1st January 2010 to 31st December 2010 was performed. The Demographic and medical history from the patients who met WHO criteria for stroke and had undergone MRI were collected and analyzed. We examined MRI data to find out early and late signs of IS and determine topography (cerebral arterial territory). Study subjects were categorized into three groups: young (<40 years), middle age (41-65 years) and elderly (>65 years). Season was categorized as: winter (December–February); summer (March–May); monsoon (June–August); and post monsoon (September- November). Time of onset of ischemic stroke was defined as the time when neurological symptoms were first noticed. It was divided into four subgroups: night (00:00–05:59 hours), morning (06:00-11:59), noon (12:00-17:59) and evening (18:00-23:59). Association between topographical distribution, season, and time of stroke onset were derived.

Result: A total of 216 subjects were included (59.3% males and 40.7% females) with median age observed at 58 years (range: 20-80 years). Middle cerebral arterial territory (MCA) was the most commonly affected (38.9%) followed by posterior cerebral artery (PCA) 13%, brainstem 13%, anterior cerebral artery (ACA) lesion in 11.1%, multiple vessel territory 9.3%, small vessel infarcts in 8.4% and cerebellum 6.5%. The rate of occurrence of stroke (33.3%) was highest in morning (0600–1159 hours) irrespective of gender or age of the patient. Summer season recorded significantly higher frequency of IS with 35.2% (P<0.05) followed by winter 27.8%, post monsoon 20.4% and monsoon 16.7%. The young (50.0%) and middle (55.6%) age group cases showed a peak incidence of ischemic stroke in summer, while in elderly age (43.4%)group the highest ischemic stroke incidence were reported in winter .

Conclusion: Acute ischemic stroke displays seasonal and diurnal characteristics according to gender, age group and anatomical distribution. These results may have important clinical implications in ischemic stroke prevention.

Author(s): Divyanshu Dubey , Anshudha Sawhney, Arvind Kavishwar, Sonjjay Pande, Devashish Dubey

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