Intussucception occurs when one part of bowel invaginates (intussusceptum) into an adjacent section (intussuscipiens) which results in intestinal obstruction and venous compression. If uncorrected it can result in arterial insufficiency and necrosis. It is the commonest abdominal emergency between 3 months and 2 years . Peak incidence is between 6 and 9 months. Most cases are idiopathic with the lead point due to enlarged Peyer's patches, Usually due to a viral infection.5% are due to polyp, Meckel's diverticulum, duplication cyst or tumour .Commonest site involved is the ileocaecal junction.
Clinical features are Intermittent colicky abdominal pain and vomiting, Each episode classically last 1-2 min and recurs every 15-20 min, there is Passage of blood - 'red currant jelly' per rectum. Per abdomen a Sausage shaped abdominal mass is felt in upper abdomen. Diagnosis confirmed with water soluble contrast enema or ultrasound.
Treatment is Resuscitation with intravenous fluids and nasogastric tube. Attempt reduction with air or contrast enema under radiological guidance. If peritonitis, shock or failed reduction requires surgery , If bowel necrosis require resection with primary anastomosis