Ileocolic Intussusception

  • Etiology: idiopathic (90%) due to hypertrophied Peyer’s patches after viral URI, consider secondary causes when > 3 years old – lymphoma / Meckel’s diverticulum / bowel wall hemorrhage in Henoch-Schonlein Purpura / polyp / inspissated stool in cystic fibrosis, invagination of part of intestine (intussusceptum) into distal intestine (intussuscipiens), intussusceptum includes mesentery as well as bowel wall and compression of mesentery leads to compromise of venous drainage which over time can lead to arterial perfusion being reduced which can lead to subsequent infarction and necrosis
  • AXR: can show small bowel obstruction, usually unremarkable so normal AXR does not rule out intussusception, Currarino’s sign of not seeing air in hepatic flexure of colon
  • US: for diagnosis – target / pseudokidney signs that are > 3 cm in transverse diameter
  • Enema: coiled spring + filling defect caused by intussusceptum
  • Treatment: pediatric surgery consult, IV fluids, ruling out peritonitis + perforation which are contraindications to reduction, air enema for reduction done prone with tight buttock seal done according to Rule of 3’s: 3 attempts each lasting 3 minutes and with bag of contrast 3 feet off table (= not exceeding a pressure of 120 mm of Hg in air enema) with end point being massive reflux of air into terminal ileum, an 18 gauge needle readily available to treat pneumoperitoneum in case of perforation
  • Clinical: peak age is 6 months, 75% in patients less than 2 years, presents by passing blood / currant jelly stool, drawing legs up to abdomen, air reduction is 80-90% successful with 0.5% perforation rate, 10% re-intussuscept within 24 hours post reduction

Cases of Ileocolic Intussusception

AXR of small bowel obstruction due to intussusception
AXR supine (left) shows decompressed loops of bowel (presumed jejunum) in the left upper quadrant and multiple dilated loops of bowel (presumed ileum) in the right lower quadrant. AXR upright (right) shows multiple air-fluid levels.
US of ileocolic intussusception
XR supine (upper left) shows a non-obstructive bowel gas pattern but suggests a soft tissue mass in the right lower quadrant. Transverse US of the right lower quadrant (upper middle) shows a soft tissue mass with a target sign measuring 3 cm in diameter while the longitudinal US (upper right) shows a pseudokidney sign. AP spot image from an air enema (bottom) shows a soft tissue mass being encountered in the cecum.
AXR of pneumoperitoneum
Supine AXR obtained during an intussusception reduction shows air outlining both the inner and outer walls of the small bowel (Rigler’s sign).
Surgical image of ileocolic intussusception
Surgical image shows an ileocolic intussusception extending into the mid ascending colon with a dusky terminal ileum (to the right) intussuscepting into the cecum (to the left). Note that the appendix (in the middle of the image) is intussuscepted with the ileum. The intussusception was reduced without great difficulty manually. No lead point was seen.