Gastroenterology · Small and Large Bowel Obstruction
The facts most likely to be tested
Sigmoid volvulus is the most common type of colonic volvulus and typically presents in elderly patients with a history of chronic constipation.
Cecal volvulus is associated with a congenital mobile cecum and is more common in younger patients compared to sigmoid volvulus.
The classic radiographic finding for sigmoid volvulus is the coffee bean sign or bent inner tube sign pointing toward the right upper quadrant.
Cecal volvulus presents on abdominal imaging as a comma-shaped or embryo-shaped dilated loop of bowel located in the left upper quadrant.
Flexible sigmoidoscopy is the initial diagnostic and therapeutic procedure of choice for sigmoid volvulus in the absence of peritonitis or gangrene.
Surgical detorsion with cecopexy or right hemicolectomy is required for cecal volvulus because endoscopic decompression is ineffective.
Emergency laparotomy is mandatory for any patient with volvulus who presents with signs of peritonitis, fever, leukocytosis, or hemodynamic instability.
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An 82-year-old male nursing home resident presents to the emergency department with a 2-day history of progressive abdominal distension, obstipation, and nausea. His medical history is significant for chronic constipation and dementia. Physical examination reveals a tympanitic, markedly distended abdomen without signs of peritonitis. An abdominal radiograph demonstrates a large, dilated loop of bowel arising from the pelvis and extending toward the right upper quadrant, resembling a coffee bean.
What is the most appropriate initial management for this patient?
Flexible sigmoidoscopy
The patient's presentation and imaging are classic for sigmoid volvulus; in the absence of peritonitis, endoscopic decompression is the first-line treatment.
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Etiology / Epidemiology
Sigmoid volvulus is common in elderly/institutionalized patients; cecal volvulus occurs in younger patients with congenital malrotation.
Clinical Manifestations
Presents with obstipation, abdominal distension, and tinkling bowel sounds. Peritonitis indicates bowel necrosis.
Diagnosis
CT scan with contrast is the diagnostic test of choice; abdominal X-ray shows the coffee bean sign.
Treatment
Flexible sigmoidoscopy is first-line for sigmoid; peritonitis requires emergent surgical resection.
Prognosis
Recurrence is high without elective surgery; mortality increases significantly with bowel ischemia.
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Epidemiology & Etiology
Sigmoid volvulus is the most common type, frequently associated with chronic constipation and high-fiber diets in the elderly. Cecal volvulus is rarer and typically results from a mobile cecum due to incomplete mesenteric fixation during development.
Pertinent Anatomy
The sigmoid colon is the most common site due to its redundant, mobile mesentery. The cecum is the second most common site, occurring when the right colon fails to fixate to the posterior peritoneum.
Pathophysiology
Axial rotation of a bowel segment around its mesenteric axis leads to closed-loop obstruction. This causes venous congestion, followed by arterial compromise and eventual bowel ischemia. If untreated, the loop undergoes gangrene and perforation.
Clinical Manifestations
Patients present with acute, severe abdominal pain, nausea, and obstipation. Physical exam reveals marked distension and tinkling bowel sounds. Peritonitis, fever, and tachycardia are signs of bowel necrosis and require immediate surgical consultation.
Diagnosis
Abdominal X-ray is the initial screening tool, classically showing the coffee bean sign. CT scan with contrast is the gold standard for confirming the diagnosis and identifying the site of obstruction. Look for the whirl sign on CT, representing the twisted mesentery.
Treatment
For sigmoid volvulus without signs of peritonitis, flexible sigmoidoscopy is the first-line treatment for decompression. If the bowel is viable, elective surgical resection is recommended to prevent recurrence. Peritonitis or failed decompression mandates emergent laparotomy with resection.
Prognosis
Recurrence rates after endoscopic decompression alone are as high as 40-50%. Bowel ischemia and perforation are the most feared complications, carrying a high mortality rate if not addressed via surgical resection.
Differential Diagnosis
Small bowel obstruction: usually presents with prior surgical history/adhesions
Colonic pseudo-obstruction: Ogilvie syndrome, lacks a mechanical transition point
Fecal impaction: common in elderly, diagnosed by digital rectal exam
Colorectal cancer: presents with progressive weight loss and change in bowel habits
Mesenteric ischemia: pain out of proportion to physical exam findings