A 58-year-old man with a history of peptic ulcer disease presents with acute onset abdominal pain, vomiting, and abdominal distension. Imaging reveals small bowel obstruction. What is the most common cause of small bowel obstruction in this clinical context?

Explanation

## Most Common Cause of Small Bowel Obstruction ### Epidemiology in India and Globally **Key Point:** Adhesions account for 60–75% of all small bowel obstructions in developed countries and approximately 40–50% in developing countries (where external hernias are more common). **High-Yield:** In a patient with a history of abdominal surgery (peptic ulcer surgery, appendicectomy, or any laparotomy), adhesions are the most likely cause of mechanical small bowel obstruction. ### Pathophysiology Adhesions form as a result of: 1. Peritoneal trauma during surgery 2. Inflammatory response and fibroblast proliferation 3. Formation of fibrous bands that kink or compress bowel loops 4. Can occur months to years after the initial surgery ### Clinical Context In this patient with a history of peptic ulcer disease (suggesting previous surgical intervention), adhesions are the most probable diagnosis. The acute presentation with classic signs of obstruction (pain, vomiting, distension) is typical. ### Comparison with Other Causes | Cause | Frequency | Risk Factors | Clinical Features | |-------|-----------|--------------|-------------------| | **Adhesions** | 60–75% (developed) | Prior abdominal surgery | Recurrent episodes, variable onset | | **Hernia** | 10–15% | Congenital/acquired defects | Palpable mass, acute onset | | **Crohn's disease** | 5–10% | IBD history | Chronic symptoms, skip lesions | | **Malignancy** | 5–10% | Age >50, weight loss | Insidious onset, constitutional symptoms | **Clinical Pearl:** Adhesions are the leading cause of small bowel obstruction in patients with prior abdominal surgery, and recurrent episodes are common due to the chronic nature of adhesion formation. ### Management Approach - Initial conservative management (nasogastric decompression, fluid resuscitation) - Surgery indicated if signs of strangulation or failed conservative management after 48–72 hours - Careful adhesiolysis during surgery to minimize recurrence