Diagnosis

A barium enema demonstrated an intussusception at the hepatic flexure which was successfully reduced.

Teaching points and Discussion:

1. Intussusception is a common abdominal emergency in young children. A delay in establishing the diagnosis leads to a delay in treatment, bowel ischemia, and bowel infarction. An early diagnosis is essential.



2. The most common is ileocolic, with the lead point proximal to the ileocecal valve. Bloody mucousy stool (currant-jelly stool) is a late sign,       resulting from engorgement of the intestine, edema, and then bleeding from the mucosa. Although this finding is known as currant jelly stools, it can resemble blood mixed with stool as in dysentery. This can easily be dismissed as being caused by gastroenteritis due to       shigella or salmonella. This pitfall can be avoided by considering the diagnosis of intussusception in all cases of bloody diarrhea and       bloody stools.



3. Males outnumber females 2:1. The 3 - 12 month old age group is the most common.



4. The triad of symptoms: a) intermittent crampy abdominal pain (episodic pain, child may appear comfortable in between episodes); b)    emesis, and c) passage of bloody, mucousy stools. Most patients with intussusception do not present with this triad, therefore it is not useful to use this set of findings to rule out intussusception.



5. An abdominal mass is not part of the triad, but this finding, that represents the leading head of the intussusception, may be helpful in establishing the diagnosis. The mass may be present in any part of the abdomen depending on where the intussusception originates and where it ends. This mass is usually palpated in the right abdomen, but in severe cases, it may be present in the left abdomen if the intussusception has passed the splenic flexure and has entered the descending colon.



6. Plain abdominal films may be normal. There may be evidence of bowel obstruction after 6-12 hours of symptoms. Thus, plain abdominal films cannot be used to rule out intussusception. However, plain films may be used to add to the body of clinical evidence prompting one to do a barium enema.



7. Radiographic signs on plain abdominal films include the target sign, the crescent sign, the absent liver edge sign, and other signs that are less specific for intussusception.

Target sign: Two approximately concentric circles of fat density to the right of the spine, due to layers of peritoneal fat surrounding and within the intussusceptum alternating with layers of mucosa and muscle. This sign resembles a very faint target, or bull's eye, or dough-nut appearance.

View a target sign example.

This radiograph shows a classic target sign in the right upper quadrant just below the liver. It resembles a chubby doughnut with a puffy center. It is very subtle. You may need to adjust the contrast control on your monitor to appreciate it. This radiograph also shows the absent liver edge sign and the crescent sign. A paucity of bowel gas is also noted.

Crescent sign: Soft-tissue density mass of the intussusceptum projecting into the colon (leading edge). If the head of the intussusceptum is projecting into a gas filled pocket, it will show itself. It often takes on a crescent shape; however, it may also merely resemble a protruding head into a gas filled pocket.