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Difficulty: HardNeonatal Disorders

A full-term male neonate (gestational age 40 weeks) is evaluated in the nursery at 48 hours of life due to progressive abdominal distension and two episodes of bilious emesis. A review of the nursing logs indicates that the infant has not yet passed meconium. Vital signs are within normal limits. Physical examination reveals a markedly distended abdomen that is soft and non-tender, with hypoactive bowel sounds. A digital rectal examination results in a sudden, explosive release of foul-smelling gas and stool. Arrange the following diagnostic and therapeutic steps in the most appropriate chronological sequence for managing this patient's likely condition.

  1. 1Obtain a plain abdominal radiograph
  2. 2Perform a water-soluble contrast enema
  3. 3Obtain a rectal suction biopsy
  4. 4Proceed with surgical resection of the affected bowel segment

Answer

The correct sequence is: 1) Obtain a plain abdominal radiograph, 2) Perform a water-soluble contrast enema, 3) Obtain a rectal suction biopsy, 4) Proceed with surgical resection of the affected bowel segment.
The correct sequence prioritizes patient safety and escalating diagnostic certainty. A plain abdominal radiograph is first to rule out life-threatening perforation. Once safety is established, a contrast enema characterizes the obstruction and identifies a transition zone. Because imaging is not definitive, a rectal suction biopsy follows to provide histological confirmation (absent ganglion cells). Only after tissue confirmation is the definitive surgical resection (pull-through procedure) performed.

Step-by-Step Solution

1
Analyze the clinical presentation to identify the underlying pathophysiology.
The patient is a term infant with delayed meconium passage, bilious emesis, abdominal distension, and a positive "squirt sign" (explosive expulsion of stool on digital rectal exam).
These findings are highly characteristic of Hirschsprung disease, caused by the failure of neural crest cells to migrate to the distal colon, resulting in an aganglionic segment that fails to relax.
2
Determine the most immediate initial intervention for a neonate with signs of bowel obstruction.
Obtain a plain abdominal radiograph.
Plain radiography is required to confirm the presence of a distal bowel obstruction (multiple dilated loops of bowel) and to rule out intestinal perforation before considering any contrast administration.
3
Select the subsequent imaging modality to narrow the differential diagnosis.
Perform a water-soluble contrast enema.
This step distinguishes Hirschsprung disease from other causes of distal obstruction (like meconium ileus) by identifying a characteristic transition zone.
4
Identify the procedure needed for definitive diagnosis.
Obtain a rectal suction biopsy.
Imaging is suggestive but not definitively diagnostic. Histological confirmation demonstrating the absence of ganglion cells is strictly required prior to any permanent surgical intervention.
5
Determine the ultimate therapeutic management.
Proceed with surgical resection of the affected bowel segment.
After pathological confirmation, the definitive treatment is removing the dysfunctional aganglionic segment to relieve the obstruction and restore continuity.

Key Concept

The management of suspected Hirschsprung disease follows a strict escalation pathway: identify obstruction and rule out perforation (plain film) → localize the defect (contrast enema) → confirm histologically (rectal biopsy) → treat definitively (surgical resection).
Estimated Time:1m 30s
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Topics

Neonatal Disorders

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