What are the common causes of bowel obstruction in a 60-year-old male?

Common Causes of Bowel Obstruction in a 60-Year-Old Male

In a 60-year-old male, the most common causes of bowel obstruction are adhesions from previous surgeries for small bowel obstruction and cancer for large bowel obstruction. 1

Small Bowel Obstruction Causes

Small bowel obstruction accounts for approximately 76% of all bowel obstructions 2. The primary causes in a 60-year-old male include:

1. Adhesions (55-75%) - Post-surgical fibrous bands are the most common cause 1

   • Risk increases with history of previous abdominal surgeries
   • Having a history of previous abdominal surgery has 85% sensitivity and 78% specificity to predict adhesive small bowel obstruction 1

2. Hernias (15-25%) 1

   • Incarcerated hernias carry a significantly higher risk of strangulation compared to other causes 2
   • Common sites include inguinal, femoral, umbilical, and incisional hernias

3. Malignancies (5-10%) 1

   • Primary small bowel tumors (adenocarcinoma, neuroendocrine tumors, gastrointestinal stromal tumors, lymphomas)
   • Metastatic disease causing extrinsic compression

4. Other causes (15%) 1

   • Carcinomatosis
   • Inflammatory bowel disease strictures
   • Intussusception
   • Radiation-induced strictures
   • Post-ischemic strictures
   • Gallstones (gallstone ileus)
   • Foreign bodies and bezoars

Large Bowel Obstruction Causes

Large bowel obstruction accounts for approximately 24% of all bowel obstructions 2. The primary causes in a 60-year-old male include:

1. Cancer (60%) 1

   • Colorectal cancer is the predominant cause in this age group
   • Previous rectal bleeding and unexplained weight loss are suggestive of colorectal cancer 1

2. Volvulus (15-20%) 1

   • Sigmoid volvulus is more common than cecal volvulus
   • Often associated with chronic constipation and redundant colon 3

3. Diverticular disease (10%) 1

   • Strictures from recurrent diverticulitis
   • Previous diverticulitis episodes may suggest diverticular stenosis 1

4. Other causes (10%) 1

   • Inflammatory bowel disease
   • Radiation-induced strictures
   • Ischemic colitis with stricture formation

Warning Signs of Complications

Certain clinical features suggest bowel ischemia or strangulation, which require urgent surgical intervention:

• Intense, untreatable pain unresponsive to analgesics 1
• Peritoneal signs on examination 1
• Hyponatremia (≤134 mmol/L) 4
• CT findings of bowel wall thickening or suspected closed loop 4

Diagnostic Approach

Multidetector computed tomography (MDCT) is the gold standard for diagnosis of bowel obstruction 5. The CT scan should focus on:

1. Confirming the obstruction
2. Determining if there is a single transition point or closed loop
3. Establishing the cause of obstruction
4. Identifying signs of complications (ischemia, perforation) 5

Clinical Pearls

• Abdominal distension is a strong predictive sign of bowel obstruction (positive likelihood ratio of 16.8) 1
• Absence of passage of flatus (90%) and/or feces (80.6%) are the most common symptoms of bowel obstruction 2
• Hernias, large bowel cancer, and adhesions are the most frequent causes of bowel ischemia (57.2%, 19.1%, 14.3%), necrosis (42.8%, 21.4%, 21.4%), and perforation (50%, 25%, 25%) 2
• In patients with cancer, malignant bowel obstruction may be due to recurrent cancer or peritoneal carcinomatosis 1

Remember that prompt diagnosis and appropriate management are crucial, as the incidence of bowel ischemia (14%), necrosis (9.3%), and perforation (5.3%) is significantly high in bowel obstruction 2.