Intussusception Workup

Updated: Dec 18, 2018
  • Author: A Alfred Chahine, MD; Chief Editor: Carmen Cuffari, MD  more...
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Workup

Approach Considerations

Laboratory investigation is usually not helpful in the evaluation of patients with intussusception, although leukocytosis can be an indication of gangrene if the process is advanced. With persistent vomiting and sequestration of fluid in the obstructed bowel, dehydration and electrolyte imbalance occur.

Ultrasonographic imaging has been found to have a high sensitivity and specificity in the detection of ileocolic intussusception. Abdominal radiographs can also reveal diagnostic characteristics of intussusception, but their sensitivity and specificity has been called into question.

If a segment of intestine is resected at the time of operative reduction, intestinal obstruction with edema, congestion, lymphocytic infiltration, and transmural infarction are typical findings.

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Radiographs

After obtaining a thorough history and performing a careful physical examination, obtain plain radiographs of the abdomen with the patient in the supine and upright positions.

Plain abdominal radiography reveals signs that suggest intussusception in only 60% of cases. (See the images below.) Plain radiograph findings may be normal early in the course of intussusception. [19] As the disease progresses, the earliest radiographic evidence includes an absence of air in the right lower and upper quadrants and a right upper quadrant soft tissue density present in 25-60% of patients.

Abdominal radiograph shows small bowel dilatation Abdominal radiograph shows small bowel dilatation and paucity of gas in the right lower and upper quadrants.
Note intussusception in the left upper quadrant on Note intussusception in the left upper quadrant on this plain film of an infant with pain vomiting. Courtesy of Kelley W Marshall, MD, Children's Healthcare of Atlanta, Emory University School of Medicine.

These findings are followed by an obvious pattern of small bowel obstruction, with dilatation and air-fluid levels in the small bowel only. If the distention is generalized and the air-fluid levels are also present in the colon, the findings more likely represent acute gastroenteritis than intussusception.

A left lateral decubitus view is also helpful. [20] If the view exhibits air in the cecum, the presence of ileocecal intussusception is highly unlikely.

Limitations of radiography

Morrison et al concluded that, when interpreted by pediatric emergency physicians, abdominal radiographs have a low sensitivity and specificity for diagnosing intussusception. [19] In a prospective experimental study, 14 pediatric emergency physicians interpreted radiographs of 50 cases of intussusception and 50 matched controls; these interpretations showed a sensitivity of 48% and a specificity of 21%. In 11% of cases, the abdominal radiographs were incorrectly interpreted as reassuring.

A study by Tareen et al concluded that abdominal radiography is not recommended for the diagnosis of intussusception in children, for the prediction of the outcome of pneumatic reduction of intussusception or for the detection of occult pneumoperitoneum. The study further noted that abdominal radiography should always be performed when clinical peritonism is present but is not otherwise necessary. [21]

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Ultrasonography and CT Scanning

Hallmarks of ultrasonography include the target and pseudokidney signs. (See the image below.)

Abdominal ultrasonography reveals the classic targ Abdominal ultrasonography reveals the classic target sign of an intussusceptum inside an intussuscipiens.

One study reported that the overall sensitivity and specificity of ultrasonography for detecting ileocolic intussusception was 97.9% and 97.8%, respectively. The authors concluded that ultrasonography should be used as a first-line examination for the assessment of possible pediatric intussusception. [22]

Ultrasonography eliminates the risk of exposure to ionizing radiation and can help to depict lead points and residual intussusceptions. It also helps to rule out other possible causes of abdominal pain. Even so, ultrasonography is highly operator dependent; therefore, interpret results with caution.

The presence of ascites and long segments of intussusception can be used as sonographic predictors of failure for nonoperative management. [23] Sonographic detection of ascites, air, and absence of blood flow in the intestinal wall strongly suggest bowel gangrene.

Computed tomography (CT) scanning has also been proposed as a useful tool to diagnose intussusception (see the image below); however, CT scan findings are unreliable, and CT scanning carries risks associated with intravenous contrast administration, radiation exposure, and sedation.

CT scan reveals the classic ying-yang sign of an i CT scan reveals the classic ying-yang sign of an intussusceptum inside an intussuscipiens.
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Contrast Enema

The traditional and most reliable way to make the diagnosis of intussusception in children is to obtain a contrast enema (either barium or air). Contrast enema is quick and reliable and has the potential to be therapeutic. [24] (See the images below.)

Barium enema shows intussusception in the descendi Barium enema shows intussusception in the descending colon.
Intussusception evident during air contrast enema Intussusception evident during air contrast enema prior to reduction. Courtesy of Kelley W Marshall, MD, Children's Healthcare of Atlanta, Emory University School of Medicine.

Exercise caution when performing contrast enema in children older than 3 years, because most of these patients have a surgical lead point, usually in the small bowel. The diagnostic and therapeutic yield of the enema is lower in these patients. Enema is contraindicated in patients in whom bowel gangrene or perforation is suspected.

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