A 2-year-old boy is brought to the emergency department after his parents found a dark red, formed stool in his diaper. He has been eating and drinking well but seems more tired than usual. The family lives on a ranch raising cattle and goats. Temperature is 37 C (98.6 F). Examination shows a pale, cooperative boy. The abdomen is soft, nondistended, nontender, and without masses. There are no anal fissures or hemorrhoids. A fecal occult blood test is positive. Laboratory results are as follows: Which of the following is most likely to confirm the diagnosis for this patient?

Question

A 2-year-old boy is brought to the emergency department after his parents found a dark red, formed stool in his diaper.  He has been eating and drinking well but seems more tired than usual.  The family lives on a ranch raising cattle and goats.  Temperature is 37 C (98.6 F).  Examination shows a pale, cooperative boy.  The abdomen is soft, nondistended, nontender, and without masses.  There are no anal fissures or hemorrhoids.  A fecal occult blood test is positive.  Laboratory results are as follows:  Which of the following is most likely to confirm the diagnosis for this patient?

Quizplus · Accepted Answer

11ec25c8_d684_3c5d_bc81_f743f101683a_MD0003_00 This patient has painless dark red stool (gastrointestinal bleed) concerning for a Meckel diverticulum, the most common gastrointestinal congenital anomaly. Meckel diverticulum results from a partial remnant of the fetal vitelline duct, an embryologic structure that typically obliterates in the first trimester. A Meckel diverticulum may contain ectopic gastric mucosa (or, less commonly, pancreatic tissue), which secretes hydrochloric acid. Acidity can cause surrounding small-bowel ulceration and subsequent bleeding, which may lead to pallor and anemia if chronic, as in this case. Stools can range in color from dark red or maroon to black depending on colonic transit time; the latter is more common in adults. Abdominal pain, diarrhea, and vomiting are uncommon. vitelline duct The best diagnostic test is a technetium-99m pertechnetate scan (Meckel scan), which shows increased uptake of technetium-99m by gastric mucosa and therefore identifies ectopic gastric tissue. This test is noninvasive, highly sensitive and specific, and emits little radiation. In symptomatic patients, surgical resection is necessary to prevent further bleeding or other complications (eg, intussusception, obstruction). Meckel scan (Choice A) CT scans cannot reliably differentiate the diverticulum from other loops of bowel. (Choices B and C) Meckel diverticulum is a potential lead point for intussusception, which classically presents as severe, intermittent abdominal pain with or without hematochezia. Workup of intussusception includes abdominal ultrasonography and/or diagnostic and therapeutic air enema. This patient has no pain, making intussusception unlikely. abdominal ultrasonography (Choice D) Stool cultures can identify the offending pathogen in bacterial colitis, which may present with bloody diarrhea, crampy abdominal pain, and fever, none of which are present in this patient. (Choice E) Milk-protein-induced allergic proctocolitis can cause painless rectal bleeding that resolves with elimination of dietary cow's milk. This non-IgE-mediated condition is virtually exclusive to infants and resolves by age 1. (Choice G) Upper endoscopy is often performed for upper gastrointestinal bleeding, which presents with hematemesis and melena (black, sticky stools), neither of which are seen in this patient. Educational objective: Meckel diverticulum often presents in young toddlers as painless lower gastrointestinal bleeding without abdominal pain, diarrhea, or vomiting. Diagnosis is with a technetium-99m pertechnetate scan, which can identify ectopic gastric mucosa. References: Meckel's scan in children: a review of 183 cases referred to two paediatric surgery specialist centres over 18 years. (http://www.ncbi.nlm.nih.gov/pubmed/23417523)

A 2-Year-Old Boy Is Brought to the Emergency Department After