An emergency medical team evaluates a 22-day-old male neonate who was rushed to the hospit… — USMLE Step 2 CK

An emergency medical team evaluates a $22$ -day-old male neonate who was rushed to the hospital after developing forceful, green-tinged emesis. His parents note that he became suddenly lethargic and irritable this morning. Previously, the infant had been breastfeeding adequately and gaining weight appropriately. Vital signs reveal significant tachycardia at $190$ /min, tachypnea at $58$ /min, and profound hypotension ( $58/34$ mm Hg). The patient appears pale, mottled, and diaphoretic. Palpation of the abdomen elicits diffuse rigidity and involuntary guarding, with visually apparent distension. Digital rectal examination yields normal-appearing stool with no gross blood. Venous blood analysis demonstrates a pH of $7.21$ , bicarbonate of $12$ mEq/L, and a lactate level of $7.1$ mmol/L. A plain radiograph of the abdomen demonstrates a gasless abdomen with a single prominent gastric bubble. Which of the following is the most appropriate next step in the management of this patient?

A
Upper gastrointestinal contrast fluoroscopy
B
Nasogastric decompression and serial abdominal examinations
Emergency exploratory laparotomyAnswer
D
Intravenous sodium bicarbonate infusion
E
Computed tomography of the abdomen and pelvis

Answer

Emergency exploratory laparotomy

The correct answer is emergency exploratory laparotomy. This neonate presents with classic signs of intestinal malrotation complicated by midgut volvulus, leading to bowel ischemia and hypovolemic/septic shock (evidenced by marked hypotension, tachycardia, poor perfusion, and severe lactic acidosis). The presence of diffuse abdominal rigidity (peritonitis) and hemodynamic instability in the setting of bilious emesis is an absolute indication for immediate surgical intervention (the Ladd procedure). There is no time for confirmatory diagnostic imaging when the patient is in extremis with an acute surgical abdomen.

Step-by-Step Solution

Identify the key clinical syndrome.

The patient is a neonate with bilious emesis, hemodynamic instability (shock), peritonitis (rigid abdomen), and severe lactic acidosis.

Recognizing bilious emesis in a neonate as a surgical emergency is the first step in directing care.

Determine the most likely underlying diagnosis.

The presentation is highly suspicious for intestinal malrotation complicated by midgut volvulus and subsequent bowel ischemia.

Midgut volvulus twists the superior mesenteric artery, leading to rapid bowel necrosis, which presents as peritonitis, shock, and elevated lactate.

Select the appropriate intervention based on patient stability.

Because the patient is hemodynamically unstable with signs of necrotic bowel, immediate surgery (exploratory laparotomy) is required.

Unstable patients with an acute surgical abdomen cannot tolerate the delay of diagnostic imaging; definitive operative management is life-saving.

Key Concept

Hemodynamically unstable pediatric patients presenting with bilious emesis and peritonitis require immediate emergency exploratory laparotomy for suspected midgut volvulus with bowel ischemia.

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