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Difficulty: MediumNeonatal Disorders

A 33-hour-old male neonate is evaluated in the nursery for jitteriness, lethargy, and poor feeding. He was born at 3939 weeks gestation to a mother with poorly controlled type 2 diabetes mellitus. His birth weight was 4.5 kg4.5\text{ kg} (9.9 lb9.9\text{ lb}). Vital signs include a temperature of 36.8∘C36.8^\circ\text{C} (98.2∘F98.2^\circ\text{F}), heart rate of 150/min150/\text{min}, and respiratory rate of 45/min45/\text{min}. Physical examination reveals a markedly plethoric (ruddy) skin appearance. Small, firm, white nodules are noted on the alveolar ridges. A peripheral venous hematocrit is 72%72\%. Capillary blood glucose is 52 mg/dL52\text{ mg/dL}. Which of the following is the most appropriate next step in management?

  1. A
    Administer an intravenous bolus of 10% dextrose in water
  2. B
    Administer empiric intravenous ampicillin and gentamicin
  3. Perform a partial exchange transfusion with normal salineAnswer
  4. D
    Apply topical oral nystatin suspension
  5. E
    Obtain an echocardiogram to evaluate for congenital heart disease

Answer

The most appropriate next step in management is to perform a partial exchange transfusion with normal saline.
This patient has symptomatic neonatal polycythemia, defined as a venous hematocrit greater than 65% accompanied by clinical signs. The maternal history of poorly controlled diabetes leads to fetal hyperglycemia and hyperinsulinemia. Hyperinsulinemia increases fetal metabolic demand and oxygen consumption, resulting in relative fetal hypoxia. This stimulates erythropoietin production, leading to increased red blood cell mass and polycythemia. The resulting hyperviscosity reduces tissue perfusion and can cause symptoms such as jitteriness, lethargy, poor feeding, plethora, and respiratory distress. In a symptomatic infant with a venous hematocrit of 72%, the definitive treatment is a partial exchange transfusion, typically with normal saline, to reduce blood viscosity without altering the circulating blood volume. This intervention prevents severe ischemic complications like cerebral infarction or necrotizing enterocolitis.

Step-by-Step Solution

1
Analyze the maternal history and birth weight.
The mother has poorly controlled diabetes, and the infant is large for gestational age (4.5 kg).
Maternal diabetes is a major risk factor for neonatal polycythemia and hypoglycemia.
2
Interpret the clinical signs and laboratory findings.
The infant is symptomatic (jitteriness, lethargy) with a plethoric appearance, a normal glucose level (52 mg/dL), and a highly elevated venous hematocrit (72%).
This confirms a diagnosis of symptomatic neonatal polycythemia and rules out hypoglycemia as the cause of the symptoms.
3
Determine the appropriate intervention for symptomatic neonatal polycythemia.
Partial exchange transfusion is selected.
Symptomatic infants with a hematocrit > 65% require a partial exchange transfusion to reduce blood viscosity and prevent ischemic organ damage.

Key Concept

Management of symptomatic neonatal polycythemia
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Topics

Neonatal Disorders

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