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Difficulty: HardPediatric Infectious Diseases

A 3-week-old boy is brought to the pediatric clinic by his mother because his 5-year-old sister developed a diffuse, pruritic, vesicular rash 2 days ago and was subsequently diagnosed with chickenpox. The mother reports having had a documented case of chickenpox during her own childhood. The patient was born prematurely at 27 weeks gestation and was recently discharged from the neonatal intensive care unit. Over the past 24 hours, the neonate has developed clear rhinorrhea and a mild cough. His temperature is 37.2°C (99.0°F), pulse is 150/min, respirations are 48/min, and oxygen saturation is 97% on room air. Physical examination shows a well-appearing neonate with scattered erythematous macules and papules on his chest. Auscultation of the lungs reveals mild, bilateral expiratory wheezes. Which of the following is the most appropriate next step in management for this patient?

  1. Administer varicella-zoster immune globulinAnswer
  2. B
    Administer the live-attenuated varicella vaccine
  3. C
    Reassure the mother that the rash is erythema toxicum neonatorum and observe closely
  4. D
    Prescribe nebulized albuterol and discharge home
  5. E
    Admit to the hospital for empirical intravenous ampicillin and gentamicin

Answer

Administer varicella-zoster immune globulin
The correct answer is to administer varicella-zoster immune globulin (VZIG). This patient has experienced a significant household exposure to varicella. Although his mother is immune to varicella, transplacental transfer of maternal IgG antibodies occurs predominantly late in the third trimester (after 32 weeks gestation). Because this infant was born at 27 weeks gestation, he did not receive adequate maternal antibodies and is considered highly susceptible to varicella infection, which can be severe and fatal in neonates. Standard guidelines dictate that premature infants born at <28< 28 weeks gestation or weighing ≤1000\leq 1000 g should receive VZIG following a significant varicella exposure, regardless of maternal immune status.

Step-by-Step Solution

1
Evaluate the risk level of the infectious exposure.
The neonate had a significant household exposure to varicella 2 days ago.
Significant exposures within a 10-day window require evaluation for post-exposure prophylaxis (PEP) to prevent severe disease.
2
Determine the neonate's underlying immune status based on maternal history and gestational age.
Although the mother has natural immunity to varicella, the infant was born at 27 weeks gestation.
Transplacental transfer of protective maternal IgG primarily occurs in the third trimester (after 32 weeks). Therefore, extreme premature infants lack maternal antibodies.
3
Select the appropriate prophylactic intervention.
Varicella-zoster immune globulin (VZIG) must be administered.
According to guidelines, premature infants born at <28< 28 weeks gestation or weighing ≤1000\leq 1000 g require VZIG after varicella exposure regardless of maternal immune status.

Key Concept

Post-exposure prophylaxis for varicella in extremely premature infants
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Topics

Pediatric Infectious Diseases

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