CONDITIONS - Sigmoid Volvulus

1. Background

Most common volvulus of the GI tract
Accounts for 5% of the causes of large bowel obstruction
 
2. Epidemiology

Increased incidence in South America, Africa and parts of Asia
More common in children where roundworm is endemic
  
3. Aetiology

Risk factors include
Anatomic defect (see pathology)
Age (more common in the elderly)
Male
High fibre diet
Chronic constipation
Patients from nursing home or mental health institutions
Mobile sigmoid colon
 
4. Pathology

Redundant loops of sigmoid colon on a long mesentery
Narrow band attaching the posterior abdominal wall to the sigmoid mesentery predisposes patients to twisting of the sigmoid colon upon its axis
 
5. Symptoms & Signs

Symptoms and signs are of those of large bowel obstruction
Abdominal pain
Absolute constipation
Abdominal distension
Empty rectum on DRE
Examine closely for signs of ischaemia e.g. PR bleeding
 
6. Diagnosis & Investigation

Diagnosis is made by a combination of history, examination and imaging
Delay in diagnosis can lead to ischaemia and perforation
Digital Rectal Exam (DRE)
Bloods: FBC, U&E's

6.1 Abdominal X-Ray
Compression of the medial walls of the two sigmoid loops produces the pathognomonic "coffee bean sign"
Loops of colon converge in the left hand side of the pelvis with loop extending to the right upper quadrant

6.2 Water Soluble Enema
May show the "birds beak" sign where contrast stops at the point of convergence of the loops
Confirms the diagnosis

7. Management
 
7.1 Conservative Management
7.1.1 Flatus tube decompression
Indicated in the elderly and in those with no signs of ischaemia
Place patient into left lateral decubitus position
Under endoscopic control with rigid sigmoidoscopy a soft rubber flatus tube is passed through the obstruction
Tube is left in place for 48 hours
 
7.1.2 Colonoscopic decompression
Indicated for patients unfit for surgery and in whom flatus decompression using rigid sigmoidscopy has failed
 
7.2 Surgical Management
Indications
Perforation
Ischaemia
Failed tube decompression
Repeated volvulus - prophylaxis against recurrence
Surgical options include
Sigmoid colectomy and primary anastomosis
Hartmann's procedure - in the presence of ischaemia/perforation