Twisting of a loop of bowel on its mesentery.

Epidemiology:- Volvulus: 3rd most common cause (∼ 10-15%) of intestinal obstruction in the United States→ Sigmoid volvulus (most common, 80%)→ Cecal volvulus (15%)- Intestinal malrotation and midgut volvulus: neonates and infants

Risk factors:- Chronic constipation, laxative abuse, antimotility drugs- Megacolon (Hirschsprung's disease, Chagas disease)- Intestinal bands/adhesions

Clinical features:- Acute onset of colicky abdominal pain- Obstipation, abdominal distention- Anorexia, nausea, vomiting

Diagnostics:- Abdominal x-ray (erect and supine) → Sigmoid volvulus: coffee bean sign (bent inner tube sign) → Cecal volvulus: kidney bean sign

Treatment:- Initial resuscitation: IV fluids; acid-base and electrolyte imbalance correction; nil per oral; placement of a nasogastric tube- Sigmoid volvulus: Nonoperative reduction (decompression via sigmoidoscopy) is successful in >70% of cases. The recurrence rate is high, so elective sigmoid colonresection is recommended.- Cecal volvulus: Emergent surgery is indicated.