A Pediatric Radiology Textbook and Pediatric Radiology Digital Library
Ileocolic Intussusception
Etiology Idiopathic (90%): — Due to hypertrophied Peyer’s patches related to viral upper respiratory infection — Is invagination or telescoping of terminal ileum (intussusceptum) through the ileocecal valve into colon (intussuscipiens) causing obstruction — Intussusceptum includes mesenteric vessels and fat as well as bowel wall and compression of mesentery which leads to compromise of venous drainage which over time can lead to arterial perfusion being reduced which can lead to subsequent bowel ischemia and infarction and necrosis
Etiology Pathologic (10%): — Increasing prevalence of pathologic lead point with increasing age (greater than 3 years old) so always look for lead point with ultrasound — Surgeon may still want reduction attempted if lead point is found in order to avoid emergency surgery — Most common pathologic lead points – Meckel diverticulum or polyp or duplication cyst or lymphoma — Less common pathologic lead points – bowel wall hemorrhage in Henoch-Schonlein Purpura or inspissated stool in cystic fibrosis or acute appendicitis
Imaging AXR: — Can show distal small bowel obstruction — Currarino’s sign of seeing soft tissue mass in hepatic flexure of colon with meniscus or cutoff sign in colon around soft tissue mass — Useful in excluding free air which is contraindication to reduction via enema — Usually unremarkable so normal AXR does not rule out intussusception so move on to US for diagnosis
Imaging US: — For diagnosis: Target sign that is greater than 3 centimeters in transverse diameter on transverse image and pseudokidney sign on sagittal image — May see lymph nodes and fat and appendix along with small bowel in intussusceptum
Note: Predictors of difficult to reduce intussusception are entrapped fluid and decreased vascularity
Note: Appendix can be part of intussusception and it does not affect reduction
Imaging Contrast Enema: Coiled spring appearance caused by intussusceptum
Imaging Air Enema: Filling defect caused by intussusceptum
DDX: — Small bowel-small bowel intussusception – size should be less than 3 centimeters, should never see fat or lymph nodes in transient small bowel-small bowel intussusception — Edematous ileocecal valve which has a small size and length and which does not involve the appendix
Complications: Longstanding intussusception can lead to bowel ischemia and necrosis and bowel perforation
Treatment: — Pediatric surgery consult — IV fluids and antibiotics — Rule out peritonitis and 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 millimeters of Hg in air enema) with end point being massive reflux of contrast or air into terminal ileum — An 18 gauge needle should be readily available to treat pneumoperitoneum in case of perforation
Note: Ileocolic intussusception can reduce spontaneously between time of diagnosis and enema and can also reduce spontaneously with induction of general anesthesia
Clinical: — Peak age is 6 months — 75% in patients less than 2 years old — Presents with intermittent abdominal pain or palpable mass or passing bloody currant jelly stool or drawing legs up to abdomen — Most common cause of obstruction in young children, — Air reduction is 80-90% successful with 0.5% perforation rate — 10% re-intussuscept within 24 hours post reduction — In children with recurrent intussusception think of pathological lead point — If adolescent has ileocolic intussusception look for pathologic lead point — Burkitt lymphoma is most common cause of intussusception in child greater than 4 years old — Meckel diverticulum and gastrointestinal duplication can be pathologic lead points — Intussusception is complication of retroperitoneal surgery in children (Wilms tumor resection)
Radiology Cases of Ileocolic Intussusception
Radiology Cases of Ileocolic Intussusception With Peritoneal Signs
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.AXR AP (left) and AXR left lateral decubitus (right) show multiple distended loops of small bowel with multiple air fluid levels. There was no gas in the colon and no free air. As the patient had peritoneal signs, no further imaging was performed.
Radiology Cases of Ileocolic Intussusception That Were Successfully Reduced With Air Enema
AXR supine (left) shows multiple dilated loops of small bowel. AXR upright (right) shows a round soft tissue mass filling the lumen of the mid transverse colon. AP image from an air enema (below) shows reduction of the soft tissue mass to the cecum just before it disappeared and a large amount of air was observed to reflux into the terminal ileum.AXR (left) shows a paucity of air in the ascending colon. AP image from an air enema (above right) shows a soft tissue mass which was encountered at the hepatic flexure. Magnified view of the mass (below right) shows it to have a coiled-spring appearance.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 (left) was unremarkable. Sagittal US of the right lower quadrant (middle) showed a pseudokidney sign in the ascending colon. Air enema encountered a mass at the ileocecal valve which was rapidly reduced with reflux of a large amount of air into the terminal ileum (right).AXR AP (left) shows a non-obstructive bowel gas pattern and a suggestion of a soft tissue mass in hepatic fluxure. AP image from an air enema (right) shows a round soft tissue mass in the hepatic flexure which was successfully reduced. The next day the pediatric radiologist received a box of pastries from the grateful family.AXR AP (left) shows a nonobstructive bowel gas pattern and a soft tissue mass over the spine, with its left border outlined by air in the transverse colon. AP image from an air enema (right) shows a large round soft tissue mass in the hepatic flexure that was successfully reduced, evidenced by a large amount of air being refluxed into the small bowel.AXR AP (above left) shows multiple dilated loops of small bowel. AP image from an UGI exam to rule out malrotation as the source of bilious vomiting (above right) shows normal position of the ligament of Treitz. Transverse US of the abdomen (middle left) shows a soft tissue mass with a target sign while sagittal US (below left) shows the mass to have a pseudokidney sign. When the enema tip was inserted in the rectum the patient passed a bloody stool. AP image from an air enema (below right) shows a mass in the hepatic flexure which was reduced on the first attempt. AXR AP (left) shows a non-obstructive bowel gas pattern and a round soft tissue mass in the right upper quadrant obscuring the inferior margin of the liver (Currarino sign). Transverse US of the mass (right) shows it to have a hyperechoic center and a hypoechoic rim (Target sign). The mass was successfully reduced, recurred and was rereduced successfully.AXR AP (left) shows a non-obstructive bowel gas pattern and a soft tissue mass in the hepatic flexure obscuring the inferior margin of the liver (Currarino sign). AP image from an air enema (above right) shows the soft tissue mass has been reduced from the hepatic flexure to the cecum. AXR AP taken after the air enema (below right) shows disappearance of the soft tissue mass from the cecum and reflux of a large amount of air into the terminal ileum.
Radiology Cases of Ileocolic Intussusception That Were Successfully Reduced With Air Enema With an Edematous Ileocecal Valve Mimicking a Residual Ileocolic Intussusception
AXR AP (left) showed an unremarkable bowel gas pattern. An air enema encountered a round soft tissue mass in the ascending colon which had been reduced to the ileocecal valve (above right) before reflux of large amount of air into the small bowel was seen. Post procedure AXR (below right) shows the large amount of air refluxed into the small bowel but there was a persistent round soft tissue mass at the ileocecal valve. US exam of this region then showed this round soft tissue mass was an edematous ileocecal valve.
Radiology Cases of Ileocolic Intussusception Unsuccessful Reductions
AXR obtained after an outside barium enema shows the cecum to have a coiled spring appearance. There is no reflux of contrast into the terminal ileum.AXR supine (above left) shows multiple dilated loops of small bowel and AXR upright (above right) shows multiple air-fluid levels. There is no air in the colon. AP image from an air enema (below) shows a soft tissue mass outlined by air in the hepatic flexure which was then easily reduced to the ileocecal valve on the first attempt but could not be reduced further on subsequent attempts. In the operating room the terminal ileum and cecum were found to be necrotic and were resected.AXR supine (left) shows a round soft tissue mass in the mid transverse colon. AP image of an air enema (right) shows the round soft tissue mass to have been reduced to the level of the ileocecal valve, however it could not be reduced further.
Radiology Cases of Ileocolic Intussusception Unsuccessful Reductions Initially That Were Eventually Successful
Outside AXR (above left) has a suggestion of a soft tissue mass in the hepatic flexure. Lateral spot image from an outside barium enema (above middle) shows a coiled spring appearance to the ascending colon. Post procedure outside AXR (above right) shows barium refluxed into the appendix but not into the terminal ileum. The soft tissue mass remains at the hepatic flexure. AP image from a repeat air enema at our institution (below left) shows a soft tissue mass outlined by air in the cecum. Post procedure AP image after the air enema (below right) shows a massive amount of air refluxed into the terminal ileum.
Radiology Cases of Ileocolic Intussusception Complications From Reduction
Supine AXR obtained during an intussusception reduction shows air outlining both the inner and outer walls of the small bowel (Rigler’s sign).AXR scout image (above left) shows a non-obstructive bowel gas pattern. AP image from the start of an air enema begun after manual reduction of the mass into the rectum (above right), shows the tip of the rectal catheter in contact with the mass in the rectum. AP image from later in the study (below left) shows the mass now in the transverse colon near the splenic flexure. Despite multiple attempts the intussusception could not be reduced further and the exam was ended when air was seen outlining the liver and both sides of the wall of the small bowel (Rigler’s sign)(below right). In the operating room the intussusception was reduced manually and a site of perforation could not be found.
Radiology Cases of Meckel Diverticulum Serving as Lead Point For Ileocolic Intussusception
Transverse US of the right lower quadrant (above) shows a round structure with a hyperechoic center and a hypoechoic rim (target sign). AXR supine (below left) shows multiple dilated loops of air-filled small bowel. Final AP image from an air enema exam (below right) shows an air filled colon with a large oval soft tissue mass in the cecum.
Radiology Cases of Juvenile Polyps Serving as Lead Point For Ileocolic Intussusception
Axial CT with contrast of the abdomen (above) at initial presentation shows a large round soft tissue mass in the region of the ascending colon that has alternating circles of soft tissue density and fat density which give it a target sign appearance. Transverse US of the abdomen obtained two weeks later (below) shows recurrence of a nearly identical appearing soft tissue mass in the region of the ascending colon that has alternating circles of decreased and increased echogenicity giving it a target sign appearance.
Radiology Cases of Lymphoid Hyperplasia Serving as Lead Point For Ileocolic Intussusception
Axial CT with contrast of the abdomen (above left) shows a mass involving the ascending colon which has a target sign appearance which on sagittal CT (above right) has a pseudokidney appearance. Transverse US of the ascending colon mass (below left) again demonstrates a target sign while the sagittal US of the mass (below right) again demonstrates a pseudokidney sign.
Clinical Cases of Ileocolic Intussusception
Clinical image shows currant jelly stools.
Surgery Cases 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. Surgical image shows forceps in a 1.5 cm perforation in the mid point of the transverse colon. The ascending colon (on the right) is distended and is full of necrotic intussuscepted ileum up to the level of the hepatic flexure.Surgical image (above) shows an ileocolic intussusception which upon reduction is seen to be caused by a Meckel diverticulum (below in center of image with forceps pointing to it) on the antimesenteric border of the small bowel.
Histopathology Cases of Ileocolic Intussusception
Histopathological image H&E stained section shows the intussusception characterized by viable small intestine on one (left) side with non-viable, intussuscepted portion of intestine on the other (right) side. Note the homogeneous, eosinophilic staining of the non-viable intestinal wall with no appreciable nuclear detail (ischemic necrosis). A few viable cells are floating in the lumen of the nonviable intestine.
