From the Guidelines
The primary causes of small bowel obstruction are adhesions, hernias, and tumors, with adhesions being the most common cause, accounting for approximately 60% of all cases. According to the most recent and highest quality study available, 1, adhesions are the leading cause of small bowel obstruction, followed by hernias and tumors. The study found that adhesions were the cause of bowel obstruction in 47.9% of cases of small bowel obstruction in patients with a virgin abdomen. Hernias, particularly internal hernias, are also a common cause of small bowel obstruction, especially after bariatric surgery, as reported in 1 and 1. Tumors, both malignant and benign, can cause obstruction by growing into the bowel lumen or by external compression. Less common causes include inflammatory bowel disease, foreign bodies, gallstones, intussusception, volvulus, and strictures from radiation therapy.
Causes of Small Bowel Obstruction
- Adhesions: bands of scar tissue that form after abdominal surgery, accounting for approximately 60% of all cases
- Hernias: particularly inguinal, femoral, and ventral hernias, responsible for about 20% of cases
- Tumors: both malignant and benign, can cause obstruction by growing into the bowel lumen or by external compression
- Inflammatory bowel disease: particularly Crohn's disease
- Foreign bodies: such as gallstones
- Intussusception: telescoping of the bowel
- Volvulus: twisting of the bowel
- Strictures: from radiation therapy
Clinical Presentation
Small bowel obstruction presents with symptoms including:
- Abdominal pain
- Distension
- Vomiting
- Constipation The pathophysiology involves mechanical blockage of intestinal contents, leading to fluid accumulation, bowel distension, and potential ischemia if blood supply is compromised.
Management
Initial management typically includes:
- Bowel rest
- Nasogastric tube decompression
- IV fluids
- Pain management Surgical intervention may be necessary for complete obstruction, strangulation, or when conservative management fails, as reported in 1 and 1.
From the Research
Primary Causes of Small Bowel Obstruction
The primary causes of small bowel obstruction include:
- Adhesions, which are the leading cause of small bowel obstruction 2
- Malignant tumors 3, 4
- Hernias 3, 4
- Volvulus 3
- Postoperative intussusception, an unusual cause of small bowel obstruction 5
- Enteroliths, a rare cause of small intestinal obstruction 6
Other Causes
Other causes of small bowel obstruction may include:
- Diverticulitis, which can cause large bowel obstructions 4
- Bezoars, which can form in patients with previous gastric surgeries 6
- Cancer, which can cause both small and large bowel obstructions 4
Diagnostic Challenges
Small bowel obstruction can pose a diagnostic challenge, especially in cases where the cause is rare or unusual, such as enteroliths 6 or postoperative intussusception 5.