A 34-year-old woman, gravida 2 para 1, at 20 weeks gestation comes to the office in November for a routine prenatal visit. She is feeling well and has had no vaginal bleeding or cramping. Several weeks ago, the patient had 2 days of fever and pharyngitis that resolved spontaneously. Her 3-year-old son and several of his playmates at day care had similar symptoms. The pregnancy has otherwise been uncomplicated; prenatal screening results from 13 weeks gestation were as follows:
| HIV-1/2 antibody | negative |
| Rapid plasma reagin | positive, 1:64 titer |
| Treponemal antibody absorption test | negative |
| Rubella antibody IgG | positive |
The patient has no chronic medical conditions and is current on her vaccinations. Vital signs are normal. The uterine fundus is below the umbilicus. Ultrasound shows a fetus with bilateral periventricular intracranial calcifications and an enlarged liver with multiple intrahepatic calcifications. The estimated fetal weight is consistent with 16 weeks gestation. Which of the following pathogens is the most likely cause of this patient's ultrasound findings?
Congenital cytomegalovirus | |
Ultrasound findings |
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Neonatal features |
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Long-term sequelae |
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This patient's ultrasound findings are likely due to congenital cytomegalovirus (CMV) infection. CMV is commonly acquired via close contact with young children, as seen in this patient, and maternal infection can result in either a subclinical or mild febrile illness. During this maternal infection, transplacental (vertical) transmission can occur and cause fetal infection. CMV spreads throughout the fetus and preferentially replicates in the placenta, liver, and central nervous system, resulting in the clinical features of fetal growth restriction, an enlarged liver with multiple intrahepatic calcifications, and bilateral periventricular intracranial calcifications (ie, tissue necrosis). Additional ultrasound findings may include hydrops fetalis, microcephaly, and ventriculomegaly. Long-term sequelae include neurologic abnormalities, sensorineural hearing loss, seizures, and development delay.
Maternal infection is diagnosed via serology, and fetal infection is diagnosed via amniocentesis. Maternal antiviral therapy is not indicated as it has not been proven to prevent fetal infection. Therefore, management is generally expectant; however, pregnancy termination may be considered for fetuses with severe congenital CMV infection identified early during pregnancy.
(Choice B) Although influenza is common in the fall and winter, influenza is neither vertically transmitted nor associated with fetal anomalies.
(Choice C) Listeria monocytogenes infection, which typically occurs after consumption of an unpasteurized dairy product, can be vertically transmitted. However, fetal infection generally results in spontaneous abortion or preterm delivery of a fetus with multiple abscesses and granulomas (ie, granulomatous infantiseptica). Ultrasound findings typically include dilated loops of bowel and ascites.
(Choice D) Parvovirus B19 infection is associated with fetal anemia and hydrops fetalis (eg, pleural effusion, ascites) rather than intracranial and intrahepatic calcifications.
(Choice E) Congenital rubella syndrome can cause fetal growth restriction and hepatomegaly. However, this is unlikely in patients with a current vaccination status and immunity to rubella (positive IgG) on first-trimester screening.
(Choice F) Congenital syphilis from a Treponema pallidum infection can cause fetal intracranial and intrahepatic calcifications. Although this patient has a positive rapid plasma reagin, the confirmatory treponemal antibody absorption test is negative, making this diagnosis unlikely.
Educational objective:
Congenital cytomegalovirus occurs due to transplacental (vertical) transmission. Ultrasound findings consistent with congenital cytomegalovirus infection include bilateral periventricular intracranial calcifications, intrahepatic calcifications, and fetal growth restriction.