Colonic Volvulus Summary

Pathophysiology

  • Axial rotation of colon on mesenteric attachments
  • Sigmoid colon most affected (76%), then caecum (22%)
  • 360° twist creates closed loop obstruction

Risk Factors

  • Older age, institutionalization, mental illness
  • Chronic constipation, megacolon
  • High-fiber diet, previous abdominal surgery

Clinical Features

  • Colicky abdominal pain
  • Inability to pass feces or flatus
  • Abdominal distension, tenderness, tympany

Investigations

  • Abdominal x-ray (75% diagnostic accuracy)
  • Coffee-bean sign, inverted U-shaped loop
  • Characteristic patterns for sigmoid vs. caecal

Management

  • Sigmoidoscopy with rectal tube for sigmoid volvulus
  • Laparotomy for caecal volvulus or complications
  • Emergency surgery if peritonitis or gangrene

Colonic Volvulus

Medical guide to pathophysiology, diagnosis, and management

Introduction

Colonic volvulus is a surgical emergency that occurs when a segment of the colon twists around its mesentery, leading to obstruction and potential compromise of blood supply. Early recognition and appropriate management are crucial to prevent serious complications.

Epidemiology

Colonic volvulus accounts for approximately 10-15% of all large bowel obstructions, with higher incidence in certain regions including Eastern Europe, Africa, and South America.

Clinical Significance

Without prompt intervention, colonic volvulus can progress to bowel ischemia, necrosis, perforation, and life-threatening sepsis.

Mortality

Mortality rates range from 17-40% in emergency settings, with higher rates in elderly patients and those with delayed diagnosis.

Pathophysiology

Mechanism of Volvulus Formation

Colonic volvulus arises following axial rotation of the colon on its mesenteric attachments: the sigmoid colon is the most frequently affected segment (76%), then the caecum (22%).

Pathophysiological Process

Rotation can be clockwise or anti-clockwise around the mesenteric axis.
A 360° twist produces a closed loop obstruction, trapping gas and fluid within the affected segment.
Fluid and electrolyte shifts result from fluid secretion into the closed loop.
Increasing pressure and tension on the colonic wall impairs blood supply.
Compromised blood flow results in ischemia, necrosis, and potential perforation.

Risk Factors

Several factors predispose individuals to developing colonic volvulus, often related to abnormal colonic mobility or changes in colonic anatomy.

Demographic Factors

  • Older age
  • Institutionalization
  • Mental illness
  • Chronic constipation

Anatomic Factors

  • Megacolon
  • Elongated colon
  • Narrow mesenteric attachment
  • Previous abdominal surgery

Lifestyle Factors

  • High-fiber diet
  • Laxative abuse
  • Diabetes (with autonomic neuropathy)

Clinical Features

Presentation

Patients with colonic volvulus typically present with signs and symptoms of large bowel obstruction, which may progress to peritonitis if ischemia develops.

Symptoms and Signs

Colicky abdominal pain - Often sudden in onset and severe
Inability to pass feces or flatus - Complete obstruction
Nausea and vomiting - Typically a late sign
Abdominal distension - Often marked and asymmetric
Abdominal tenderness - May indicate developing ischemia
Tympanic abdomen - Due to trapped gas
Abnormal bowel sounds - May be hyperactive early, then hypoactive

Investigations

Prompt and appropriate imaging is essential for diagnosis and to guide management decisions in suspected colonic volvulus.

Abdominal X-ray

Colonic volvulus is identified in 75% of x-rays
Characteristic coffee-bean shape seen with the "apex" locating the origin of volvulus
Sigmoid volvulus:
  • Dilated inverted U-shaped loop of colon projected towards the right side of abdomen
  • Opposing colonic walls produce radio-opaque line
  • Proximal large and small bowel dilation may also be evident
Caecal volvulus:
  • Dilated right colon rotates to the left side
  • Dilated small bowel may also be present
  • Caecum appears in epigastrium or left upper quadrant

Additional Investigations

CT Scan

Provides more detailed visualization of the twist ("whirl sign") and can assess for complications like ischemia or perforation.

Contrast Enema

May show characteristic "bird's beak" sign at the point of obstruction, but is contraindicated if perforation is suspected.

Laboratory Tests

Complete blood count, electrolytes, lactate (to assess for ischemia), and coagulation studies.

Management

Urgent Intervention Required

Immediate management is necessary due to risk of perforation from either ischemia of the affected segment or obstruction.

Sigmoid Volvulus

Flexible or rigid sigmoidoscopy with insertion of a rectal tube
Should be performed immediately after diagnosis
Ensure the affected segment is viable before proceeding
The rectal tube is fixed and left in situ for 24 hours
Repeat abdominal x-ray to ensure decompression has been successful
Where peritonitis or mucosal gangrene is identified, emergency midline laparotomy is required

Caecal Volvulus

Laparotomy is the primary treatment
Diagnosis is often made at laparotomy due to difficulty in preoperative diagnosis
Colonoscopic and percutaneous decompression has been attempted but is reserved for patients who are not candidates for surgery
Attempted decompression may only delay necessary surgical intervention

Surgical Options

Detorsion Only

Simple untwisting of the volvulus, but has high recurrence rates (up to 40-50%).

Resection with Primary Anastomosis

Preferred approach for viable bowel without significant contamination.

Resection with Stoma

Hartmann's procedure or ileostomy/colostomy for compromised patients or non-viable bowel.

Complications

Serious Sequelae

Without prompt diagnosis and appropriate management, colonic volvulus can lead to life-threatening complications.

Bowel Compromise

  • Intestinal perforation
  • Intestinal ischemia
  • Bowel necrosis
  • Peritonitis

Systemic Complications

  • Sepsis
  • Intra-abdominal abscess
  • Fluid and electrolyte imbalance
  • Septic shock

Long-term Issues

  • Recurrent volvulus
  • Short bowel syndrome (after extensive resection)
  • Adhesive bowel obstruction
  • Stoma-related complications