Seasonal Variation in Cases of Acute Appendicitis.

Objectives: To investigate whether the incidence of acute appendicitis increases in summer and whether complicated cases present more in summer.

Methods: A single-center cross-sectional, retrospective study on 697 cases of appendicitis admitted in the year 2018. Inclusion criteria: patients admitted with acute appendicitis who underwent appendectomy of all ages. Exclusion criteria: conservative management. Analysis was performed using Microsoft Excel. Pearson correlation coefficient was calculated to assess the correlation between monthly incidence of appendicitis and mean temperature in that month.

Results: Fifty-one patients who were managed conservatively were excluded. Accordingly, 646 patients were included. Ages ranged from three to 77 years. Males comprised the majority (500, 77.4%). Gangrenous, perforated, and purulent appendices were regarded as complicated appendicitis. The highest number of cases were admitted in summer (234), comprising 36.2% of cases. Complicated cases were equal to 65, of which 23 (35.4%) were admitted in summer and 30 (46.2%) in winter. The highest number of cases was during the month of July (68), while the lowest (40) was during February. This corresponded to the highest recorded mean temperature (36.2°C) and second lowest (19.8°C), respectively. Moderate positive correlation (Pearson's R 0.5183) between the monthly incidence of appendicitis and the mean temperature is noted.

Conclusion: More cases of appendicitis were noted during summer. Monthly incidence correlated positively with the temperature. Larger numbers over several years are needed to draw better conclusions and reach the possible causes behind such variation.