Seasonal Pattern of Acute Appendicitis in Basrah

Appendicitis is the most common acute surgical condition of the abdomen. The aim of the project is to study the seasonal variation in the incidence of acute appendicitis in Basrah and its correlation to gender, age, presentation and length of hospital stay of affected patients. Patients with acute appendicitis who admitted to the surgical unit in Basrah General hospital during the period from January 2010 to December 2013 were prospectively evaluated according to the demographic features, particularly age and sex, length of hospital stay, seasonal variation and the postoperative outcome. Out of 1261 patients included in this study 57% patients were males and 43% of patient were females with age range from 3-70 years. All the patients treated surgically by open and laparoscopic means. 34 patients found to have perforated appendix, 25 patients presented with abdominal mass and 7 patients were presented with appendicular abscess. A significant seasonal effect was observed, with the rate of acute appendicitis being higher in the summer months. It is concluded that acute appendicitis is more common in males, in those aged 10-19years, and during the summer months.


Introduction
The most common emergent surgical operation in the world is appendicectomy. [1] It is reported that about 7% of people in the world underwent appendectomy due to acute appendicitis (AA) during their life. The rate of appendectomy over the life for male patients is 12% and for female patients is 25%, during approximately a 10-year period from 1987 to 1997. [2], [3] It is observed that the rate of appendectomy for acute appendicitis has reported at 10 per 10,000 patients per year. [2], [3] It is observed that the second to the fourth decades are the most frequent ages of patients affected by acute appendicitis during their life reporting that 31.3 years as a mean age and 22 years as a median age. [2], [3], [4] Consistently, other report has observed that in infant, acute appendicitis is relatively rare, and becomes increasingly common in childhood and early adult life, reaching a peak incidence in the adolescents and early 20s. after middle age, the risk of developing acute appendicitis is quite small. [5] It is shown that the male is slightly more affected than female (male: female ratio 1.2-1.3:1). [5], [2], [3] showing that there is approximately equal incidence of acute appendicitis among males and females before puberty. [5] To the best of our knowledge and although acute appendicitis is a common surgical condition, we could not find any report studying the seasonal pattern of acute appendicitis in Basrah city and generally, little is known about this point. Hence, this subject was studied in this project in one hand as well as gender and age variations in other hand and examining their influence or correlation to the complications of acute appendicitis and subsequently the length of hospital stay for patients underwent appendicectomy.

Patients and Methods
This is a cross-section prospective study of patients who underwent appendicectomy for acute appendicitis admitted to Basrah General Hospital, department of surgery from January 2010 to December 2013. The demographic features, length of hospital stay, seasonal variation and post-operative outcome were assessed in this study. population in current study were divided by sex and age into 7 groups (0-9, 10-19, 20-29, 30-39, 40-49, and ≥50 years).
In current study the diagnosis of acute appendicitis were established by history, examination and investigations in term of leukocyte count, urinalysis and ultrasound exam in many of these cases. All the normal appendices were excluded from the study.
In southern Iraq, the year is divided into two well-marked seasons with short transitional periods between the long hot rainless Summer (May to October) and comparatively short cool winter (December to February). [6] SPSS version 16 was used for all the statistical assessments and analysis.

Results
One thousand two hundred and sixty one patients included in this study, the mean age of the patient is 21. age range from 3-70years, 727 patients were males (57.7%) and 534 patients were females (42.3%) as in table 1. Monthly and seasonal fluctuations of the incidence of acute appendicitis are shown in figure 1 and 2 respectively. It shows increase in incidence of acute appendicitis in May to October (Summer) in comparison to December to February (Winter). This study shows that 520 patients (41%) were presented in Summer in comparison to 293 (23.2%) and 248 (20%) in winter and autumn respectively. Whereas in short spring season only 200 patients (15.8%) were presented with acute appendicitis (Figure 2). This shows that there was statistically significant seasonal pattern variation in the incidence of acute appendicitis, which was evident and peaked in summer and dipped in spring (P value 0.01). Sixty six patients were presented with complicated appendicitis. Thirty four patients (3.4%) presented with perforated appendix, 25 (1.9%) patients presented with abdominal mass and 7 (0.05%) patients presented with appendicular abscess (Figure 3). The current study showed that complicated appendicitis in male (3.5%) more than the female (1.66% ) as shown in table 2. This might be explained by more overall number of male 727 (57.7%) with acute appendicitis in comparison to female patients 534 (42.3%) and male to female ratio is 1.36:1. The complications of acute appendicitis was observed mainly in patients in age group 40 and over (table 3). Complicated appendicitis in current study was significantly correlated to age variation (P value 0.01). Complicated appendicitis in this study was significantly distributed over the different seasons of year and showed more complicated appendicitis in summer probably due to more overall cases of acute appendicitis (P value 0.02) as in table 4. It was found that the mean length of hospital stay for patients with acute appendicitis was 2 days and the mean length of hospital stay for patients with complicated appendicitis was 4 days. There was no difference in the length of hospital stay between males and females and between patients presented in summer and winter. But this parameter linked to whether the case associated with complications or not.

Discussion
In the current project the highest incidence of acute appendicitis was observed in the summer months and the lowest incidence in the spring months and this represents seasonal variation. This comes in accord with the results of other reports. [7] In other report, a higher incidence of acute appendicitis has been observed in the summer months and a low incidence in the winter months. [2], [8] In the current study, the highest incidence of acute appendicitis was observed in people aged 10-19 years, both males and females. This finding is consistent with the results of other reports. [7], [8], [9], [10], [11], [12] In all age groups, a higher incidence of appendicitis were observed in this study in male patients. Similar result was mentioned in the work of others. [8], [9].
The aetiology of differences in presentations of patients with acute appendicitis in terms of sex, age and seasonal variations are not clear. The higher incidence of acute appendicitis in the summer may be explained in a view of longer summer period in our region. [6] In addition, it is known that the growth of many microorganisms such as Salmonella species is much more in summer than other seasons like winter. Hence, Summer is blamed to provide an approximately a favorable or even optimal conditions for culture media. [13] In this study, the complications of acute appendicitis reported mainly in patients in age group 40 and over. This might be attributed to a delay in the presentation of those patients or the diagnosis was late. This is possibly due to the unnecessary usage of analgesia particularly for patients in such age groups. In other records they observe a high perforation rate in patients in the 0-9 year age group and those older than 50 years. [9] In addition, in current study, acute appendicitis in current study was obviously correlated to gender variation possibly explained by more overall number of male with acute appendicitis in comparison to female patients but there was not correlated to seasonal variation. In addition, more complicated acute appendicitis in summer observed in this study could be attributed to more over all patients with acute appendicitis in this season.
The mean length of stay for patients underwent appendicectomy comes in accord with results of other workers. [9], [14] It was observed that the difference in length of hospital stay strongly related to whether the case complicated or not complicated appendicitis and it is not linked to the seasonal, gender and age variations. This finding is agreed upon it in other reports. [9]

Conclusion
Acute appendicitis is more common in males, in people aged 10-19 years, and during the summer months particularly in May. the complicated acute appendicitis mostly seen in older age groups and the mean length of hospital stay is more among patients with complicated appendicitis in comparison to the non-complicated appendicitis.