Hirschsprung Disease Workup

Updated: Aug 02, 2018
  • Author: Justin P Wagner, MD; Chief Editor: BS Anand, MD  more...
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Workup

Laboratory Studies

Chemistry panel

For most patients, electrolyte and renal panel findings are within reference ranges. Children presenting with diarrhea may have findings consistent with dehydration. Test results may aid in directing fluid and electrolyte management.

Complete blood cell (CBC) count

This test is obtained to ensure that the preoperative hematocrit and platelet count are suitable for surgery. In most cases, values are within the reference ranges.

Coagulation studies

These studies are obtained to ensure that clotting disorders are corrected before surgery. Coagulation parameters are expected to be within the reference ranges.

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Imaging Studies

Plain abdominal radiographs may show distended bowel loops with a paucity of air in the rectum.

With regard to barium enema, avoid washing out the distal colon with enemas before obtaining the contrast enema because this may distort a low transition zone. The catheter is placed just inside the anus without inflation of the balloon to avoid distortion of a low transition zone and perforation. Radiographs are taken immediately after hand injection of contrast and again 24 hours later.

The classic finding of Hirschsprung disease is a narrowed distal colon with proximal dilation; however, the findings are difficult to interpret in neonates (age < 1 mo) and do not demonstrate this transition zone in approximately 25% of the time. [45] Retention of rectal contrast for longer than 24 hours after the barium enema also suggests a diagnosis of Hirschsprung disease.

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Other Tests

Anorectal manometry detects the relaxation reflex of the internal sphincter after distention of the rectal lumen. This normal inhibitory reflex is presumed absent in patients with Hirschsprung disease. [46] Swenson initially used this test. In the 1960s, it was refined but has fallen out of favor because of its many limitations. Sedation is usually necessary. Although some authors find this test useful, false-positive results have been reported in up to 62% and false-negative results have been reported in up to 24% of cases. Because of these limitations, anorectal manometry is not commonly performed in the United States.

Echocardiography and chromosomal analyses may be warranted to evaluate for any associated congenital conditions.

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Procedures

Full-thickness rectal biopsy

The definitive diagnosis of Hirschsprung disease is confirmed by a full-thickness rectal biopsy demonstrating the absence of ganglion cells. The specimen must be obtained at least 1.5 cm above the dentate line because aganglionosis may normally be present below this level. Disadvantages of full-thickness rectal biopsy include the necessity of general anesthesia and the risks of bleeding and scarring.

Suction rectal biopsy

Simple suction rectal biopsy has been used to obtain tissue for histologic examination. Rectal mucosa and submucosa are sucked into the suction device, and a self-contained cylindrical blade excises the tissue. The distinct advantage of the suction biopsy is that it can be easily performed at the bedside. The diagnostic yield of the full-thickness rectal biopsy is significantly better than that of the suction biopsy.

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Histologic Findings

Acetylcholinesterase staining reveals hypertrophied nerve trunks throughout the lamina propria and muscularis propria layers of the bowel wall. Although acetylcholinesterase histochemistry can be a useful ancillary technique to help in the diagnosis and preoperative planning, [47] studies have suggested that immunohistochemical (IHC) staining for calretinin might be more accurate than acetylcholinesterase staining in diagnosing congenital aganglionosis in suction biopsy specimens. [48, 49]

Guinard-Samuel and colleagues evaluated the diagnostic value of calretinin IHC for Hirschsprung disease in 131 pediatric rectal biopsies. Of the 131 biopsies, 130 were accurately diagnosed based on calretinin staining. When an additional 12 cases were considered doubtful based on the standard evaluation method, they were accurately diagnosed with calretinin IHC. The investigators found calretinin superior to acetylcholinesterase to complete histology. [49]

In another study that evaluated the diagnostic value of calretinin IHC staining compared with standard hematology and eosin (H&E) staining of rectal suction biopsies over 1 year in 188 children with Hirschsprung disease, Tran et al confirmed the disease in 80 children (42.6%), with 1 false positive, no false negatives, and no serious complications associated with the procedure. [50] Calretinin and H&E staining both had a 100% sensitivity, but whereas the specificity was 99.1% for calretinin staining, it was 85.2% for H&E.

Yang and colleagues identified the presence or absence of ganglion cells via IHC staining for calretinin and microtubule associated protein-2 (MAP-2) in 52 samples of normal and aganglionic bowel. Calretinin IHC correctly identified ganglia in 11 samples originally reported as false positives from surgical pathology reports. [51]

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