A 16-day-old male infant, born at 27 weeks gestation, is being evaluated in the neonatal i… — USMLE Step 2 CK

A $16$ -day-old male infant, born at $27$ weeks gestation, is being evaluated in the neonatal intensive care unit for sudden clinical deterioration. For the past $24$ hours, he has been managed for necrotizing enterocolitis with bowel rest, nasogastric decompression, intravenous fluids, and broad-spectrum antibiotics. Over the last $2$ hours, the infant has developed recurrent apnea and profound bradycardia. His temperature is $35.1^\circ\text{C}$ ( $95.2^\circ\text{F}$ ), heart rate is $190$ /min, respiratory rate is $70$ /min, and blood pressure is $40/20 \text{ mm Hg}$ . Physical examination reveals a grossly distended, shiny, and erythematous abdomen with absent bowel sounds. Capillary refill time is $5$ seconds. A stat bedside cross-table lateral abdominal radiograph reveals massive pneumoperitoneum. Which of the following is the most appropriate next step in the management of this patient?

A
Continue conservative medical management and perform serial abdominal examinations
Proceed with immediate exploratory laparotomy or peritoneal drainageAnswer
C
Transport the patient to the radiology department for a contrast-enhanced abdominal computed tomography scan
D
Discontinue broad-spectrum antibiotics and await specific sensitivities from blood cultures
E
Administer intravenous furosemide and restrict total daily fluid intake

Answer

Proceed with immediate exploratory laparotomy or peritoneal drainage

The correct answer identifies that the infant has suffered an intestinal perforation, a life-threatening complication of necrotizing enterocolitis. The cross-table lateral radiograph showing massive pneumoperitoneum (free air) confirms the perforation. In the setting of NEC, pneumoperitoneum is an absolute indication for immediate surgical intervention, which may consist of an exploratory laparotomy with bowel resection or, in highly unstable extremely low birth weight infants, primary peritoneal drainage.

Step-by-Step Solution

Assess the patient's clinical and hemodynamic status.

The premature infant demonstrates signs of severe septic shock, including hypothermia, tachycardia, tachypnea, hypotension, and prolonged capillary refill.

Recognizing instability dictates the urgency of intervention and precludes unsafe diagnostic transfers.

Interpret the physical examination and radiographic findings.

The shiny, erythematous abdomen combined with massive pneumoperitoneum on the radiograph confirms full-thickness intestinal perforation.

Abdominal wall erythema and pneumoperitoneum are hallmark signs of advanced (Stage IIIB) necrotizing enterocolitis with perforation.

Determine the definitive treatment based on findings.

Immediate surgical intervention (laparotomy or primary peritoneal drainage) is indicated.

While necrotizing enterocolitis is initially managed medically, the development of a pneumoperitoneum is an absolute indication for emergency surgery to control the source of sepsis.

Key Concept

The absolute indication for surgical intervention in a neonate with necrotizing enterocolitis is the presence of pneumoperitoneum (intestinal perforation) or rapid clinical deterioration despite maximal medical therapy.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic