A newborn boy is evaluated in the nursery an hour after delivery. The infant was born via vaginal delivery to a 20-year-old primigravid mother who had routine prenatal care. The pregnancy was complicated by mild gestational hypertension without preeclampsia. The mother developed a fever 2 days ago and a vesicular rash on her face yesterday. On the day of delivery, the rash spread to her chest and abdomen and became intensely pruritic. She went into labor later that day and delivered the infant without difficulty. Skin-to-skin contact between the mother and infant was deferred due to the maternal rash. Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. The boy weighs 2.95 kg (6 lb 8 oz). Vital signs and physical examination are normal. The mother does not recall having similar symptoms previously, but the father had a similar rash during his childhood. Which of the following is the most appropriate management of this infant?

Question

A newborn boy is evaluated in the nursery an hour after delivery.  The infant was born via vaginal delivery to a 20-year-old primigravid mother who had routine prenatal care.  The pregnancy was complicated by mild gestational hypertension without preeclampsia.  The mother developed a fever 2 days ago and a vesicular rash on her face yesterday.  On the day of delivery, the rash spread to her chest and abdomen and became intensely pruritic.  She went into labor later that day and delivered the infant without difficulty.  Skin-to-skin contact between the mother and infant was deferred due to the maternal rash.  Apgar scores were 8 and 9 at 1 and 5 minutes, respectively.  The boy weighs 2.95 kg (6 lb 8 oz).  Vital signs and physical examination are normal.  The mother does not recall having similar symptoms previously, but the father had a similar rash during his childhood.  Which of the following is the most appropriate management of this infant?

Quizplus · Accepted Answer

11ec25c8_d6b5_5ef3_bc81_ebf1be75e1c6_MD0003_00 This mother's fever and pruritic, vesicular rash are consistent with a primary outbreak of varicella-zoster virus (VZV), or chickenpox. VZV is transmitted via aerosolized droplets and is extremely contagious. Therefore, postexposure prophylaxis (PEP) is recommended for exposed individuals who are not immune, including patients who have not received 2 doses of VZV vaccine or who have not had confirmed varicella infection. A single dose of VZV vaccine does not provide sufficient protection to consider a patient immune. For immunocompetent individuals, PEP is limited to immunization with the live VZV vaccine. However, for high-risk patients who cannot receive VZV vaccine, PEP is achieved by administering passive immunization with varicella-zoster immunoglobulin (VZIG). Patients eligible for VZIG include neonates, pregnant women, and immunocompromised patients. VZIG for neonatal PEP is effective if maternal infection developed 5 days before to 2 days after delivery. (Choice A) VZV vaccine is the recommended method of PEP for patients who are eligible for the vaccine. However, VZV vaccine is a live-virus vaccine and is contraindicated for patients age <1 year. (Choice B) Close observation and follow-up is not indicated in this case as >90% of at-risk, exposed individuals develop varicella and neonatal varicella is a severe disease that usually progresses to systemic involvement (eg, meningoencephalitis, hepatitis). Therefore, PEP is indicated for this newborn. (Choice D) Testing this infant for protective antibody (ie, varicella-specific IgG) is not useful. This infant has not had time to make his own IgG, and because IgG takes 2-3 weeks to develop after illness, the mother will not have transferred any varicella-specific IgG to the infant via the placenta. Therefore, this infant lacks protective antibody. (Choice E) Antiviral therapy (eg, acyclovir) would be indicated if the infant develops varicella disease. However, antiviral therapy has not been shown to be effective for PEP; VZV vaccine or VZIG (for patients who cannot receive vaccine) are the recommended agents. (Choice F) Viral testing is used for diagnosis rather than prevention, and effective PEP in this infant is likely to prevent varicella disease. Furthermore, the incubation period for varicella is 2-3 weeks, and viral testing at 24 hours is likely to be negative even in infected infants. Educational objective: Postexposure prophylaxis is indicated for newborns born to mothers with varicella developing 5 days before to 2 days after delivery. Prophylaxis is achieved by administering varicella-specific immunoglobulin to the infants, who are too young to receive live varicella-zoster virus vaccine. References: Perinatal varicella. (http://www.ncbi.nlm.nih.gov/pubmed/23281363) Varicella-zoster virus (chickenpox) infection in pregnancy. (http://www.ncbi.nlm.nih.gov/pubmed/21585641)

A Newborn Boy Is Evaluated in the Nursery an Hour