An exceptional cause of intestinal obstruction: intussusception due to a large colonic polyp
Colonic intussusception represents a condition in which one intestinal segment - called the intussusceptum - 'telescopes' inside of another, causing a mechanical intestinal obstruction; herein, the pathologic lead point is a large polyp, which pulls the colonic wall and associated mesocolon within the engulfing segment - called the intussuscipiens (Fig. 1-3). It represents a rare cause of intestinal obstruction in adults and accounts for 1-5% of all obstructions. After the invagination, acute abdominal pain occurs, accompanied by continuous vomiting and bloody stools. The clinical diagnosis is difficult and requires a high index of suspicion - an abdominal mass of unspecified aetiology is identified at abdominal palpation. Abdominal tomography with contrast represents the investigation of choice. Abdominal ultrasound is fast and inexpensive but operator dependent. Also in obese patients, the thick abdominal wall limits the correct visualization of the abdominal contents. When intestinal obstruction occurs, the distended intestinal loop also limits the use of echography. The treatment recommendation in the cases of intussusception is the resection of the affected colonic segment due to the high risk that the respective polyp is malignant. If wall ischemia is present the resection should be extended in accordance with the length of the necrotic colonic segment.