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Difficulty: EasyPediatric Gastrointestinal Disorders

A 2-year-old boy is brought to the pediatric clinic by his parents after they noticed a large amount of dark red blood in his diaper this morning. The parents report the child has been entirely asymptomatic otherwise; he has had no fever, vomiting, abdominal pain, diarrhea, or changes in his appetite. His medical history is unremarkable, and he has reached all developmental milestones appropriately. Vital signs are within normal limits for his age. Physical examination reveals a soft, non-tender abdomen with normal active bowel sounds. Rectal examination shows dark blood in the vault but no anal fissures, skin tags, or palpable masses. Which of the following is the most appropriate next diagnostic test for this patient?

  1. Technetium-99m pertechnetate scanAnswer
  2. B
    Computed tomography scan of the abdomen
  3. C
    Nasogastric tube placement and gastric lavage
  4. D
    Reassurance and dietary modification
  5. E
    Intravenous administration of broad-spectrum antibiotics

Answer

Technetium-99m pertechnetate scan
The correct answer is a technetium-99m pertechnetate scan. The patient's presentation of painless, large-volume lower gastrointestinal bleeding in a toddler is the classic presentation for Meckel diverticulum. Meckel diverticulum often contains ectopic gastric mucosa, which secretes hydrochloric acid that ulcerates the adjacent normal ileal mucosa, leading to painless bleeding. The technetium-99m pertechnetate scan (Meckel scan) specifically identifies this ectopic gastric tissue, making it the most accurate initial diagnostic test.

Step-by-Step Solution

1
Analyze the patient's clinical presentation.
The patient is a 2-year-old boy with a large volume of painless, dark red rectal bleeding and no other systemic or gastrointestinal symptoms.
Identifying the nature of the bleeding (painless lower gastrointestinal bleed) and the patient's age points toward a specific congenital etiology.
2
Determine the most likely diagnosis.
Meckel diverticulum is the most common congenital abnormality of the gastrointestinal tract and classically presents in toddlers as painless hematochezia.
The bleeding is caused by ulceration of normal adjacent small bowel mucosa due to acid secretion from ectopic gastric tissue within the diverticulum.
3
Select the appropriate diagnostic study.
A technetium-99m pertechnetate scan (Meckel scan) is the diagnostic test of choice.
Pertechnetate has a high affinity for gastric mucosa and will concentrate in the ectopic gastric tissue, allowing for visualization and confirmation of the diagnosis.

Key Concept

Diagnosis of Meckel diverticulum in a toddler presenting with painless hematochezia.
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Topics

Pediatric Gastrointestinal Disorders

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