Overview
Volvulus
1. Clinical Overview
Summary
Volvulus is the twisting of a segment of bowel on its mesentery, leading to closed-loop obstruction and vascular compromise (ischaemia). If untreated, it progresses rapidly to gangrene, perforation, and sepsis. The two main types are:
- Sigmoid Volvulus (~80%): Commonest in elderly, institutionalised patients with chronic constipation.
- Caecal Volvulus (~20%): Occurs in younger patients with a congenitally mobile caecum. Sigmoid volvulus can often be decompressed endoscopically (flatus tube), but recurrence is high, and definitive treatment is surgery. Caecal volvulus almost always requires surgery. [1,2]
Clinical Pearls
The "Coffee Bean" Sign: Classic AXR finding of Sigmoid Volvulus. A massively dilated, inverted-U-shaped sigmoid loop arising from the pelvis, pointing towards the Right Upper Quadrant.
Recurrence after Flatus Tube is High (50-90%): While endoscopic decompression is the immediate treatment for uncomplicated sigmoid volvulus, definitive surgery (sigmoid colectomy) is usually required to prevent recurrence.
Sigmoid Volvulus = Old, Constipated, Institutionalised: The classic patient is an elderly, debilitated individual in a nursing home with chronic constipation and a massively redundant sigmoid colon.
Caecal Volvulus = Younger, Surgery Usually Needed: Unlike sigmoid, caecal volvulus is rarely decompressible endoscopically. Patients are often younger. Right Hemicolectomy is the definitive treatment.
2. Epidemiology
Demographics
| Type | Typical Patient | Age | Risk Factors |
|---|---|---|---|
| Sigmoid | Elderly, Neuropsychiatric illness, Institutionalised | 60-80 years | Chronic Constipation, Megacolon, High Fibre Diet (Africa, Asia), Chagas Disease |
| Caecal | Younger | 30-60 years | Congenitally Mobile Caecum (Incomplete fixation), Pregnancy, Previous Surgery/Adhesions |
Incidence
- Volvulus accounts for ~5-10% of large bowel obstruction in Western countries.
- Much higher incidence in Africa and Middle East (endemic constipation, high fibre diet leading to redundant colon).
3. Pathophysiology
Mechanism
- Predisposing Factors: A long, redundant sigmoid colon (from chronic constipation) or a mobile caecum (congenital malrotation) allows the bowel to twist.
- Twisting (Volvulus): The bowel rotates around the axis of its mesentery, typically 180-360 degrees or more.
- Closed-Loop Obstruction: Both the inflow (proximal) and outflow (distal) points are obstructed. The segment becomes isolated and distends massively with gas.
- Venous Congestion: Mesenteric veins are compressed first, causing venous congestion and oedema of the bowel wall.
- Arterial Occlusion: As twisting progresses, mesenteric arteries are compressed, leading to ischaemia.
- Gangrene & Perforation: Without intervention, the bowel wall necroses and perforates, causing faecal peritonitis and sepsis.
Sigmoid vs Caecal
| Feature | Sigmoid Volvulus | Caecal Volvulus |
|---|---|---|
| Site | Sigmoid Colon | Caecum (& Ascending Colon) |
| Direction of Twist | Anticlockwise typically | Axial twist or "Bascule" (folding) |
| Mesentery | Long, redundant sigmoid mesentery | Mobile caecum (unfixed) |
| Content | Faeces (distal colon) | Ileal effluent (proximal) |
4. Differential Diagnosis (Large Bowel Obstruction)
| Condition | Key Features |
|---|---|
| Colorectal Carcinoma | Commonest cause of LBO. History of change in bowel habit, PR bleeding. "Apple-core" on Barium Enema. |
| Diverticulitis with Stricture | Prior episodes of diverticulitis. Inflammation on CT. |
| Faecal Impaction / Pseudo-obstruction (Ogilvie's) | Massive colonic dilatation without mechanical obstruction. Seen in unwell/immobile patients. |
| Intussusception | More common in children. "Target sign" on imaging. |
| Adhesive Small Bowel Obstruction | Prior abdominal surgery. SB affected, not large bowel. |
5. Clinical Presentation
Sigmoid Volvulus
Caecal Volvulus
Signs of Ischaemia / Gangrene (RED FLAGS)
Symptoms
Insidious onset of abdominal distension, constipation, colicky abdominal pain. Vomiting is a late feature.
Signs
Massively distended abdomen (tympanic). May be asymmetric. Tenderness is initially mild unless ischaemia develops.
6. Investigations
Plain Abdominal X-Ray (AXR)
- Sigmoid Volvulus: "Coffee Bean Sign" (Large, inverted U-shaped loop arising from pelvis, pointing towards RUQ). "Bent Inner Tube Sign". Loss of haustral markings. Apex "points" to the Right Hypochondrium.
- Caecal Volvulus: "Embryo Sign" / "Kidney Bean Sign". Dilated caecum in LUQ (displaced from its normal RIF position). Single large loop.
CT Abdomen / Pelvis (with IV Contrast) - Gold Standard
- Demonstrates the "Whirl Sign" (Twisted mesentery and vessels).
- Identifies the transition point.
- Assesses for bowel wall ischaemia (Lack of enhancement, Pneumatosis, Portal venous gas).
- Rules out alternative diagnoses.
Bloods
- FBC: Raised WCC (Inflammatory response, ischaemia).
- U&Es: Dehydration, AKI.
- LFTs: May elevate with sepsis.
- Lactate: Elevated suggests ischaemia.
- Blood Gas: Metabolic acidosis in severe cases.
- Group & Save / Crossmatch: For potential surgery.
7. Management
Management Algorithm
SUSPECTED VOLVULUS
(LBO + Classic X-Ray/CT Findings)
↓
RESUSCITATE (IV Fluids, NBM, NGT)
↓
SIGNS OF ISCHAEMIA / PERITONITIS?
┌──────────┴──────────┐
YES NO
↓ ↓
EMERGENCY DECOMPRESSION ATTEMPT
LAPAROTOMY (Depends on Type)
↓ ↓
RESECTION ┌──────┴──────┐
(Hartmann's if SIGMOID CAECAL
unstable, or ↓ ↓
Primary Anastomosis RIGID SURGERY
if stable) SIGMOIDOSCOPY (Right
+ FLATUS TUBE Hemicolectomy)
↓ ↓
SUCCESSFUL?
┌────┴────┐
YES NO
↓ ↓
ELECTIVE EMERGENCY
SIGMOID LAPAROTOMY
COLECTOMY
(Prevent
Recurrence)
Initial Resuscitation (All Patients)
- A-E Approach.
- IV Fluids: Crystalloid resuscitation for dehydration.
- NG Tube: For decompression.
- NBM (Nil By Mouth).
- IV Antibiotics: If signs of sepsis or ischaemia.
- Catheterise: Monitor urine output.
- Analgesia.
Sigmoid Volvulus (Uncomplicated)
- Endoscopic Decompression (First-Line):
- Rigid Sigmoidoscopy (or Flexible Sigmoidoscopy).
- A Flatus Tube is passed beyond the twist into the sigmoid loop.
- A gush of gas and faeces indicates successful decompression.
- The tube is left in situ for 24-48 hours to prevent immediate re-twist.
- Success Rate: ~80%.
- Elective Surgery (Definitive):
- Sigmoid Colectomy (Primary Anastomosis or Hartmann's if high risk).
- Recommended due to high recurrence rate (50-90%) after flatus tube alone.
Sigmoid Volvulus (Complicated - Ischaemia/Perforation)
- Emergency Laparotomy.
- Sigmoid Resection + Primary Anastomosis (if stable, clean field) OR Hartmann's Procedure (End Colostomy + Rectal Stump) if unstable or contaminated.
Caecal Volvulus
- Surgery is almost always required (Endoscopic decompression is rarely successful due to anatomy).
- Right Hemicolectomy (Resection of caecum and ascending colon) is the definitive treatment.
- Caecopexy (fixing the caecum without resection) has a high recurrence rate and is generally avoided.
8. Complications
Of Volvulus Itself
- Bowel Ischaemia / Gangrene.
- Perforation.
- Faecal Peritonitis.
- Sepsis / Septic Shock.
- Death (Mortality 10-30% if ischaemia/perforation present).
Post-Operative
- Anastomotic Leak.
- Stoma Complications (Hartmann's).
- Recurrence (Especially after non-resective procedures).
9. Prognosis and Outcomes
- Early Presentation (No Ischaemia): Good outcome with decompression and elective surgery.
- Late Presentation (Ischaemia / Perforation): High mortality (10-30%).
- Recurrence: High (50-90%) if only decompressed without definitive resection.
10. Evidence and Guidelines
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Colonic Volvulus | ASCRS (2017) | Endoscopic decompression for uncomplicated sigmoid. Resection for recurrent or complicated. Right Hemicolectomy for caecal. |
| Emergency Surgery | ASGBI | Hartmann's vs Primary Anastomosis based on patient stability and contamination. |
Landmark Evidence
- Retrospective Series: Show that recurrence after flatus tube alone is 50-90%, supporting elective colectomy after initial decompression.
11. Patient and Layperson Explanation
What is Volvulus?
Volvulus is when a loop of your bowel twists around itself, like wringing out a towel. This twist blocks the bowel and cuts off its blood supply. If not treated quickly, the bowel can die (gangrene) and burst.
What causes it?
- Sigmoid Volvulus: Usually happens in older people who have had long-term constipation. The bowel becomes long and floppy, making it easier to twist.
- Caecal Volvulus: Happens in younger people whose first part of the large bowel (caecum) isn't attached properly from birth.
How is it treated?
- Untwisting with a Tube (Sigmoid): For the sigmoid type, we can often pass a tube through the back passage to untwist the bowel and release the pressure. This is a temporary fix.
- Surgery: We often need an operation to remove the twisted section of bowel to stop it from happening again. In emergencies, you might wake up with a stoma bag (where the bowel comes out onto your tummy).
12. References
Primary Sources
- Vogel JD, et al. Clinical Practice Guidelines for Colon Volvulus and Acute Colonic Pseudo-Obstruction. Dis Colon Rectum. 2016.
- Halabi WJ, et al. Sigmoid Volvulus: A Nationwide Analysis of Treatment Patterns and Outcomes. Ann Surg. 2014.
13. Examination Focus
Common Exam Questions
- X-Ray Finding: "Coffee Bean Sign?"
- Answer: Sigmoid Volvulus. Points to RUQ.
- Management: "First-line for uncomplicated Sigmoid Volvulus?"
- Answer: Rigid Sigmoidoscopy + Flatus Tube decompression.
- Complication: "Why is recurrence high after flatus tube?"
- Answer: The underlying redundant colon remains. Definitive sigmoid colectomy is needed.
- Surgery: "Caecal Volvulus treatment?"
- Answer: Right Hemicolectomy.
Viva Points
- Closed-Loop Obstruction: Explain why volvulus is more dangerous than simple obstruction (both ends blocked, rapid ischaemia).
- Hartmann's vs Primary Anastomosis: Discuss factors influencing decision (Contamination, Stability, Surgeon experience).
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.