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Difficulty: HardPediatric Gastrointestinal Disorders

A 33-week-old female infant is rushed to the emergency department by her parents after she began forcefully vomiting green-tinged fluid earlier in the day. She has vomited several times and has become increasingly lethargic over the past few hours. Her parents note that she had a normal bowel movement yesterday. The pregnancy was uncomplicated, and she was born at full term.

Vital signs reveal a heart rate of 185185/min, respiratory rate of 6060/min, and blood pressure of 62/3462/34 mm Hg. Her temperature is 37.9∘37.9^\circ C (100.2∘100.2^\circ F). On physical examination, the infant appears pale and poorly responsive. Capillary refill time is 55 seconds. Abdominal evaluation shows marked distension, absent bowel sounds, and involuntary guarding with rigidity when palpated. Additionally, there are scattered erythematous macules with central tiny yellow pustules on her anterior trunk.

Laboratory results are as follows:

Arterial blood gas:
pH: 7.217.21
pCO 2_2: 3232 mm Hg
HCO 3−_3^-: 1212 mEq/L

Serum lactate: 6.86.8 mmol/L (Normal: 0.50.5 - 2.22.2 mmol/L)

A plain radiograph of the abdomen displays a few dilated loops of small intestine without any gas in the distal bowel. There is no evidence of free intraperitoneal air.

Which of the following is the most appropriate next step in the management of this patient?

  1. A
    Upper gastrointestinal fluoroscopic contrast study
  2. B
    Intravenous acyclovir therapy
  3. Surgical abdominal explorationAnswer
  4. D
    Computed tomography of the abdomen with intravenous contrast
  5. E
    Intravenous sodium bicarbonate infusion for isolated metabolic acidosis

Answer

Surgical abdominal exploration
The correct approach for this patient is emergent surgical abdominal exploration. Bilious emesis in a neonate is a cardinal sign of intestinal obstruction, most threateningly due to malrotation with midgut volvulus. In a classic presentation without signs of ischemia, the next best step is an upper gastrointestinal contrast study. However, this infant presents with overt hemodynamic instability (shock, capillary refill of 5 seconds, lactic acidosis) and peritonitis (abdominal rigidity and involuntary guarding). These findings are highly specific for strangulated, ischemic bowel. In any patient with an acute surgical abdomen and peritonitis, especially a neonate with suspected volvulus, diagnostic imaging must be bypassed to perform an immediate exploratory laparotomy (Ladd procedure) to untwist the bowel and preserve viable intestine.

Step-by-Step Solution

1
Analyze the primary presentation.
A neonate presenting with bilious (green-tinged) emesis.
Bilious emesis in a neonate is considered a surgical emergency (typically midgut volvulus) until proven otherwise.
2
Evaluate the patient's hemodynamic status and physical examination findings.
The patient exhibits signs of severe shock (tachycardia, hypotension, prolonged capillary refill) and peritonitis (rigid, guarded abdomen).
These findings indicate compromised bowel perfusion and likely necrosis (strangulation), moving the patient out of the diagnostic pathway and into the emergent resuscitation/surgical pathway.
3
Interpret the laboratory and imaging data in the context of the clinical picture.
Lactic acidosis and a mixed acid-base disorder are present. X-ray shows dilated loops with absent distal gas.
The severe lactic acidosis confirms tissue ischemia. The concurrent respiratory acidosis (inadequate respiratory compensation) suggests impending respiratory failure, likely secondary to abdominal distension and shock.
4
Determine the single most appropriate next intervention.
Surgical abdominal exploration must be performed immediately.
When midgut volvulus leads to peritonitis and hemodynamic instability, diagnostic imaging (like an upper GI series) is bypassed in favor of emergent laparotomy to salvage the ischemic bowel.

Key Concept

Management algorithm for neonatal bilious emesis and midgut volvulus
Estimated Time:2m 0s
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Topics

Pediatric Gastrointestinal Disorders

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