From the Guidelines
Small bowel obstruction is most commonly caused by adhesions, which account for approximately 55-75% of cases, followed by hernias, malignancies, and other less common causes. The etiology of small bowel obstruction can be attributed to various factors, including:
- Adhesions from previous abdominal surgeries, which form as scar tissue develops, creating bands that can trap segments of intestine 1
- Hernias, where portions of bowel protrude through weakened areas in the abdominal wall 1
- Malignancies that can grow and block the intestinal lumen, such as carcinomas, lymphoma, and neuroendocrine tumors 2, 3
- Inflammatory bowel disease causing strictures, such as Crohn's disease 1
- Foreign bodies, gallstones (gallstone ileus), intussusception (telescoping of bowel into itself), volvulus (twisting of the bowel), and congenital abnormalities 1, 3
- Less common causes include radiation enteritis, endometriosis involving the bowel, and bezoars (collections of undigested material) 1, 3
The pathophysiology of small bowel obstruction involves either mechanical blockage of the intestinal lumen or functional impairment of intestinal motility, leading to accumulation of fluid and gas proximal to the obstruction 1. This distension triggers vomiting, abdominal pain, and if left untreated, can progress to ischemia, necrosis, and perforation of the bowel wall, resulting in peritonitis and sepsis 1, 2.
According to the most recent study 3, adhesions are also a common cause of small bowel obstruction in patients with a virgin abdomen, accounting for approximately 47.9% of cases. Other etiologies reported for small bowel obstruction in virgin abdomen include malignant or benign tumors, bezoar, small bowel volvulus, intussusception, and Meckel’s diverticulum 3.
It is essential to note that the management of small bowel obstruction depends on the underlying cause and may involve non-operative management, such as bowel decompression, water-soluble contrast agents, and fluid resuscitation, or surgical exploration in cases of suspected malignancy, internal hernia, or other complications 2.