The Effects of Temperature and Prothrombotic Conditions on Cerebral Venous Sinus Thrombosis Frequency: An Institutional Experience

OBJECTIVES: The pathogenesis of cerebral venous sinus thrombosis (CVST) is complex and involves the interplay of underlying provocative factors. Upon observing a higher frequency of CVST cases presenting to our hospital in summer, we hypothesized that CVST may be influenced by variations in climate. MATERIALS AND METHODS: A retrospective review of all patients who were diagnosed with CVST at a tertiary care hospital in Pakistan between January 2010 and December 2019 was conducted. After dividing patients into groups based on the type of risk, the frequency of CVST in these groups between four seasons (spring, summer, fall, and winter) was compared. RESULTS: A total of 256 patients diagnosed with CVST were included, of which 129 were female and 127 were male. The mean age was 41.7 ± 15.2 years. Of the total patients, 91.4% had some sort of risk factor, either systemic (162 patients) or local (72 patients), while 22 patients did not have any identifiable risk factor. The number of patients with more than one known risk factor was 93 (36.3%). Of the total number of patients, 96 (37.5%) patients had hyperhomocysteinemia, followed by 85 patients (33.2%) with a prothrombotic risk factor other than hyperhomocysteinemia and 44 (17.2%) patients with central nervous system infections. The most commonly affected sinuses were a combination of the transverse sinus and sigmoid sinus (21%), There was a statistically significant seasonal variation in CVST cases among all patients (P = 0.03) and in the systemic risk factor group (P = 0.05), with the highest number of cases occurring in the summer season. CONCLUSIONS: CVST may be influenced by seasonal changes in atmospheric temperatures and humidity, especially in patients with underlying prothrombotic risk factors.