Volvulus of the Transverse Colon

Volvulus of the transverse colon is torsion of the transverse colon around its mesentery, causing a closed-loop obstruction and vascular compromise. It is the rarest form of colonic volvulus, accounting for 1 to 4% of cases (sigmoid volvulus accounts for about 60 to 75% and cecal volvulus about 20 to 30%). It occurs at all ages, mostly in adults aged 40 to 70, with a slight male predominance.

Predisposing factors

• A long, redundant transverse colon with a narrow mesenteric base and fixation at the flexures
• Chronic constipation and a high-fiber diet
• Megacolon (including Chagas disease and Hirschsprung disease), psychiatric disease and neurological disease
• Previous abdominal surgery, adhesions, pregnancy and colonic distension
• Malrotation and congenital bands

Mechanism: the loop twists, usually in a counterclockwise direction, and bowel and mesenteric vessels are strangled. The result is massive distension, venous congestion, ischemia, gangrene and perforation. Mortality is about 10 to 35%, and is higher with gangrene. Recurrence after decompression alone is high (up to 50 to 90%). Complications: gangrene, perforation, peritonitis and sepsis.

• Sudden onset of severe colicky abdominal pain, marked distension, vomiting and obstipation
• A tympanic abdomen, often with the distended loop palpable in the epigastrium
• Previous similar episodes that resolved spontaneously (about a third)
• Tachycardia, fever, peritonism and shock in gangrene or perforation
• Red flags: peritonitis, hypotension, rising lactate, free air and bowel wall pneumatosis

1. Abdominal radiograph: a grossly dilated transverse colon in an inverted U shape, rising into the upper abdomen, often with a double air-fluid level, haustral markings and loss of the normal flexures. Small bowel dilatation and collapse of the distal colon.
2. CT of the abdomen and pelvis with intravenous contrast (sensitivity over 90%): a whirl sign of twisted mesentery, a bird's beak at the transition, a dilated closed loop, and signs of ischemia (wall thickening, reduced enhancement, pneumatosis, free fluid and free gas).
3. Contrast enema (water-soluble): a bird's beak taper at the point of obstruction, when CT is not available and perforation is not suspected.
4. Laboratory tests: full blood count, C-reactive protein, creatinine, electrolytes, lactate and blood gases.

Differentials: sigmoid or cecal volvulus, colonic pseudo-obstruction, obstructing colon cancer, adhesive small bowel obstruction, toxic megacolon.

1. Resuscitation: nil by mouth, nasogastric tube, IV crystalloid 20 mL/kg initially then by response, urinary catheter and electrolyte correction.
2. Without peritonitis or ischemia:
   • Endoscopic detorsion with a flexible colonoscope, with a decompression tube left in place for 24 to 48 hours. Success is lower than for sigmoid volvulus.
   • Early elective surgery on the same admission, because of the high recurrence rate.
3. Surgery (emergency, for gangrene, perforation, peritonitis or failed decompression):
   • Resection of the non-viable segment with extended right hemicolectomy or transverse colectomy.
   • Primary anastomosis in a stable patient with viable bowel, with a defunctioning stoma if the patient is high risk.
   • End colostomy or ileostomy (Hartmann-type) in unstable patients.
4. Elective options after endoscopic decompression: transverse colectomy with anastomosis, subtotal colectomy in megacolon, or colopexy (less favored because of recurrence).
5. Prophylaxis: cefazolin 2 g IV as a single dose before incision (3 g if over 120 kg), with metronidazole 500 mg IV as a single dose. Continue piperacillin-tazobactam 4.5 g IV every 6 hours for 4 to 7 days if there is gangrene or perforation. Enoxaparin 40 mg SC once daily for 7 days.
6. Prevention of recurrence: treat constipation with macrogol 3350 17 g orally once to twice daily and a high fluid intake.
7. Complications: anastomotic leak (5 to 15%), sepsis, wound infection, ileus and recurrence.

Follow-up at 2 and 6 weeks. Counsel on the return of obstructive symptoms.