University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• In children suspected of having intussusception, how does ultrasonography compare to contrast enema in terms of accuracy?

Clinical Bottom Lines

1. US for the initial diagnosis of intussusception:
Advantages:  1) Allows rapid and confident diagnosis or exclusion by noninvasive test  with lack of ionizing radiation, 2) useful in making alternative diagnosis, 3) useful in characterizing lead points.
Disadvantages:  1) Experienced sonographer needed, 2) not therapeutic.
2. If vague abdominal symptoms, plain abdominal radiographs provide useful initial screening procedure – may find adynamic ileus, pneumonic consolidation, appendicolith, or other diagnoses.
3. Contrast enema is reasonable for classic presentations (triad of intermittent abdominal pain, vomiting, and right upper quadrant mass) to avoid duplication of investigation.
4. Surgery for shock, necrosis, perforation, lead points, or irreducible intussusception.

Summary of Key Evidence

1. Objective: Determine correlation of ultrasound and air enema in establishing diagnosis of intussusception.  Design: prospective descriptive cohort.  Setting: tertiary care pediatric ER.  Participants: all 245 were examined for correlation of ultrasound and air enema.  Interventions:  questionnaire, ultrasound, and air enema.  Results:  Intussusception ruled out by US in 97.4%.  Alternate US findings comprised 27% of negative cases.
2. Summary:
Sensitivity     96.7%¹                   Specificity     95.5%
LR +            21.4                        LR -              0.035
PPV             92.6%                    NPV             98%

Additional Comments

• Poor inter-rater reliability is common in plain abdominal radiographs for intussusception, thus limiting its usefulness.  In a study of 182 suspected cases, 60 pts had intussusception by subsequent air enema.  Three observers agreed intussusception to be present or absent in only 7 of these 60 cases.²
• This study also prospectively evaluated clinical predictors based on questionnaire, history, and physical examination.  88 of 245 candidates were assessed for predictors.  Excellent positive predictors were identified (see below). However, no reliable negative predictors were found.

 

Predictors	PPV	p-value
RUQ mass	94%	0.0001
Gross blood in stool	80%	0.014
Gross blood on rectal exam	78%	0.01
Triad: intermittent abdominal pain, Vomiting, RUQ mass	93%	<0.001

Citation

1. Harrington L, et al.  Ultrasonographic and clinical predictors of intussusception. Journal of  Pediatrics. 1998; 132(5): 836-9.
2. Sargent MA, et al. Plain abdominal radiography in suspected intussusception: a reassessment.  Pediatric Radiology. 1994; 24(1):17-20.
3. Del-Pozo G, et al.  Intussusception in Children: Current Concepts in Diagnosis and Enema Reduction.  Radiographics. 1999; 19(2):299-319.

CAT Author: Uptal Patel, MD

CAT Appraisers: John G. Frohna, MD

Date appraised: December 6, 1999