Large bowel obstruction is a blockage of the colon, most often from colon cancer, followed by sigmoid volvulus and diverticular strictures. If the ileocecal valve stays closed, the colon swells like a closed loop and the cecum may perforate.
Key symptoms
- Gradual belly swelling
- No passage of stool or gas
- Crampy lower abdominal pain
- Late nausea and vomiting, sometimes feculent
- Recent change in bowel habits or weight loss
What you find on exam
- Marked distension, tympanic to percussion
- High-pitched or absent bowel sounds
- Check for hernias and do a rectal exam for a mass
- Signs of peritonitis: guarding, rebound, fever, fast pulse
Tests
- CT abdomen and pelvis with contrast: site and cause
- Abdominal X-ray: dilated colon; coffee bean sign in sigmoid volvulus
- Blood count, electrolytes, kidney function, lactate
- Cecum wider than 12 cm raises concern for perforation
Treatment basics
- Nothing by mouth, IV fluids, nasogastric tube if vomiting
- Correct electrolytes
- Sigmoid volvulus without ischemia: endoscopic detorsion, then elective surgery
- Cancer: surgical resection, or a colonic stent as a bridge
- Emergency surgery for perforation, ischemia or peritonitis
Red flags
- Peritonitis, fever or rising lactate
- Cecum wider than 12 cm or severe right lower tenderness
- Signs of shock
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.