A toddler with acute onset of intestinal obstruction. He had vomiting of bilious fluid and abdominal distension
A portion of the small bowel (intussusceptum) has telescoped into the immediately adjacent distal segment (intussuscipien). The invaginated portion, propelled by peristalsis, has pulled the mesentery along leading to bowel obstruction, and compression of lymphatics and vessels in the mesentery. If this is left too long, haemorrhagic infarction will occur, with possible perforation.
Sometimes, a physical abnormality such as a polyp or a Meckel diverticulum is seen causing the intussusception.