A 15-Year-Old Boy with Abdominal Pain

Posted by • August 17th, 2012

In the latest Case Record of the Massachusetts General Hospital, a 15-year-old boy had intermittent abdominal pain and diarrhea for 8 months. The abdomen was mildly tender. There was iron deficiency and occult blood in the stool. A diagnostic test was performed.

In an older child presenting with abdominal pain and an abdominal CT scan showing intussusception without a distinct mass, it is likely that the patient has an ileocolonic intussusception with a pathological lead point — possibly a small-bowel polyp or a vascular lesion not visible on imaging — and this would require surgical intervention.

Clinical Pearls

How does a disaccharidase deficiency present?

Disaccharidase deficiency, particularly lactase deficiency, should be considered when abdominal pain occurs intermittently after lactose exposure. As colonic bacteria ferment undigested lactose, hydrogen and other gases are produced that may cause abrupt cramping. Diarrhea occurs, since the lactose serves as a luminal osmotic agent. Lactase persistence after infancy is less common in Asian populations than in populations of European descent.

What are the clinical manifestations of Yersinia enterocolitica infection?

Yersinia enterocolitica is one organism that may cause chronic symptoms of diarrhea and occult blood in the stool of an otherwise well-appearing individual; when it affects the terminal ileum, it may mimic Crohn’s disease, with stool blood and leukocytes, diarrhea, and abdominal pain. The organism is difficult to isolate from commensal bowel flora in stool culture, and a single stool culture may not be sufficient for identifying the bacteria. Many microbiology laboratories do not routinely look for yersinia in stool cultures, so it is important to specify this request if Y. enterocolitica is suspected.

Morning Report Questions

Q: What are the clinical manifestations and epidemiology of intussusception?

A: Periods of pain alternating with pain-free periods are typical in patients with intussusception. Eighty percent of cases of intussusception occur in children less than 24 months of age, and only 5% of cases occur in adults. The major difference between childhood and adult intussusception is that a precipitating lesion (or “lead point”) is found in approximately 10% of childhood cases and 90% of adult cases. Bleeding is not common in classic childhood intussusception and usually occurs only when there is bowel ischemia.

Q: How common is an isolated colonic adenoma in a child?

A: Isolated colonic adenomas occur in children but are exceedingly rare, with a reported incidence of less than 1 to 3% among all nonsyndromic intestinal polyps. The pathogenesis and natural history of isolated pediatric adenomas are not well understood. Billingham et al. found no cancers in 10 patients under 20 years of age who had solitary colorectal adenomas and were followed for an average of 10 years, suggesting that most isolated adenomas are truly incidental. More recently, however, isolated adenomas have been described in patients with variant forms of hereditary  onpolyposis colorectal cancer.

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