Master the board step 3

Master the Boards: USMLE Step 3
Prevention
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Perform first-trimester screening and have mother avoid infected individuals.
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Immunize seronegative women after delivery.
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No postexposure prophylaxis is available.
A 24-year-old child-care worker is 29 weeks pregnant and is currently working.
One of the children was diagnosed with rubella last week. Rubella antigen testing
is performed and her IgG titer is negative. What is the risk of neonatal transmission
in this patient? What is the next step in management?
a. Give anti-rubella antibodies
b. Give betamethasone
c. Give rubella vaccine now
d. Give rubella vaccine after delivery
e. Ultrasound of the fetus
Answer: D. There is no postexposure prophylaxis available, and immunization during
pregnancy is contraindicated (live vaccine). The only correct management is to await
normal delivery and give vaccination to the mother after delivery.
Cytomegalovirus (CMV)
CMV is also in the family Herpesviridae, HHV-5.
Congenital CMV syndrome is the most common congenital viral syndrome in
the United States. CMV is the most common cause of sensorineural deafness
in children. CMV is spread by infected body fluid secretions.
The greatest risk for vertical transmission occurs with primary infection
(infection rate is 50 percent).
Most mothers develop asymptomatic infections or describe mild, mononucleosis-like
symptoms. About 10 percent of infants with congenital CMV
infection are symptomatic at birth.
Manifestations include intrauterine growth restriction, prematurity, microcephaly,
jaundice, petechiae, hepatosplenomegaly, periventricular calcifications,
chorioretinitis, and pneumonitis.
Diagnostic Testing
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Send CMV IgM and IgG levels from the mother:
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IgG (+) / IgM (–) indicates past exposure and no risk for primary infection.
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IgG (+) / IgM (+) or IgG (–) / IgM (+) indicates recent infection.
Prevention
· · Follow universal precautions with all body fluids. Avoid transfusion with
CMV-positive blood.
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