Acute intestinal obstruction (AIO) remains a critical surgical challenge worldwide, accounting for a significant proportion of emergency admissions. It represents a complex clinical condition characterized by the partial or complete blockage of intestinal contents, potentially leading to severe complications such as bowel ischemia, perforation, and systemic sepsis if not promptly diagnosed and managed [1]. The global burden of AIO is substantial, with an estimated incidence of 350–500 cases per 100,000 people annually [2].

The etiological spectrum of AIO is vast and varies significantly with age, geography, and healthcare infrastructure. Mechanical obstructions dominate and include causes such as adhesions, tumors, hernias, volvulus, and congenital anomalies, while functional and pseudo-obstructions constitute a smaller subset [3,4]. In developing countries, infectious etiologies like abdominal tuberculosis remain relevant, whereas in developed settings, postoperative adhesions and malignancies are more frequent [5].

Clinically, AIO presents with nonspecific but classic symptoms including abdominal pain, distension, vomiting, and obstipation. Accurate diagnosis relies on a combination of clinical acumen and imaging modalities, including abdominal X-rays, ultrasonography, and CT scans [6]. Prompt surgical intervention, especially in mechanical obstructions with signs of strangulation, is crucial to reduce morbidity and mortality.

Given the variation in causes across demographics, this study aims to evaluate the incidence and etiology of AIO across all age groups in a tertiary care centre. Identifying the most common causes within different age brackets can assist clinicians in optimizing early diagnosis and appropriate management strategies.

This prospective observational study was carried out in the Department of Surgery at a tertiary care centre over a two-year period, from October 2022 to October 2024. The required sample size was calculated based on the formula for estimating a population proportion, with p = 0.36, d = 0.09, and Z = 1.96, yielding a minimum sample size of 110 patients.

All patients presenting with clinical and radiological features suggestive of acute intestinal obstruction and requiring surgical management were included after obtaining informed consent. Patients presenting with non-obstructive emergencies or who declined participation were excluded. Data were collected using a predesigned proforma documenting demographic details, clinical findings, imaging results, intraoperative findings, and final diagnosis.

The collected data were compiled in Microsoft Excel and analyzed using Minitab version 13. Descriptive statistics such as frequencies and percentages were calculated, and the chi-square test was applied for inferential analysis. A p-value less than 0.05 was considered statistically significant.

A total of 110 patients were enrolled. The most affected age group was 0–20 years (36.36%). The incidence declined with advancing age. However, male predominance i.e. 68 (61.82%) were noted.

Table 1: Age & gender distribution of patients with acute intestinal obstruction.

Adhesions were the most common cause (27.27%), followed by neoplasms (17.27%) and volvulus (12.73%).

Table 2- incidence of acute intestinal obstruction by etiology.

Hypertension was the most common comorbidity (23.64%), followed by heart disease (14.55%) and obesity (10.91%).

Table 3- Association between comorbidities and postoperative complications.

Acute intestinal obstruction (AIO) presents a diverse spectrum of etiologies across various age groups, with findings from this study revealing notable patterns in its incidence and causes. The highest incidence of AIO was observed in individuals under 40 years of age, with the largest concentration (36.36%) in the 0–20 year age group. These findings challenge the conventional view that AIO primarily affects older populations, contrasting with previous studies, such as Udo et al. (2023), who reported peak incidence in middle-aged adults [7]. The observed age distribution suggests a need for broader diagnostic consideration, extending beyond the elderly.

A significant male predominance (61.82%) was observed in the cohort, consistent with studies by Poudel et al. (2022) and Jena et al. (2021) [2,8]. This gender disparity may reflect biological factors, as well as differences in exposure to risk factors such as trauma, surgical procedures, and healthcare access, which might contribute to the higher incidence in males [8].

Adhesions emerged as the predominant cause of AIO in this study, accounting for 27.27% of cases, aligning with global reports by Catena et al. (2019) and Markogiannakis et al. (2007) [3,4]. The dominance of adhesions is a well-established finding in surgical literature, particularly in adults with a history of prior abdominal surgery. However, in contrast, the frequency of neoplasms and volvulus was notably higher in older age groups, reinforcing the age-related shift in the types of etiologies encountered [2]. This finding mirrors the results seen in studies from more developed healthcare settings, where malignancies and volvulus are often the leading causes of AIO in older individuals [2].

Interestingly, the frequency of intussusception and abdominal tuberculosis, particularly among younger patients, stands out in these findings. These etiologies are commonly observed in pediatric populations and reflect endemic infectious disease patterns in developing regions [5]. The presence of such causes emphasizes the need for tailored diagnostic and treatment strategies for younger patients, who are more likely to present with infectious or congenital conditions [5]. Rare etiologies, such as congenital atresia, Hirschsprung’s disease, and necrotizing enterocolitis (NEC), were also identified in the study, further highlighting the diverse, age-dependent nature of AIO [6]. These findings underscore the importance of considering a wide range of differential diagnoses when evaluating pediatric and adolescent patients.

The diverse etiological spectrum revealed by this study reinforces the necessity of age-specific diagnostic approaches. In adults, a history of prior abdominal surgery should prompt clinicians to consider adhesions as the leading cause of obstruction [3]. In contrast, younger patients, particularly those presenting with AIO for the first time, may require heightened suspicion for congenital anomalies or infectious causes, such as tuberculosis [5]. Acknowledging these age-related differences can significantly improve diagnostic accuracy, leading to more effective and timely interventions [6].

Overall, these findings underscore the critical importance of early and precise etiological diagnosis in the management of AIO. The predominance of surgically correctable causes further highlights the role of prompt surgical intervention in reducing morbidity and mortality [3]. By improving the understanding of varying etiological patterns across age groups, clinical decision-making can be enhanced, surgical planning optimized, and ultimately, patient outcomes improved in the management of AIO.

Acute intestinal obstruction (AIO) presents a diverse spectrum of etiologies across all age groups, with adhesions remaining the leading cause. The highest incidence was observed in the 0–20 year age group, with male predominance. Younger patients often presented with congenital or infectious causes, while older individuals showed a higher incidence of neoplasms and volvulus. Early and accurate etiological diagnosis is crucial for effective surgical management, as most cases are surgically treatable. Comorbidities, especially hypertension, significantly impacted postoperative outcomes, emphasizing the importance of preoperative optimization. Timely intervention, particularly in mechanical obstructions, is essential to reduce morbidity and mortality, ultimately improving patient outcomes in AIO.

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