CHAPTER 9: INFECTIONS

9.1 CYTOMEGALIC INCLUSION DISEASE

EPIDEMIOLOGY/GENETICS

Definition Cytomegalovirus (CMV) is a large, enveloped DNA herpesvirus. Adult infection is frequently asymptomatic, but fetal infection may cause severe damage to multiple organ systems. CMV is transmitted in adults by bodily secretions. Fetal exposure occurs transplacentally.

Epidemiology CMV is the most common cause of in utero infection; approximately 0.5% to 1% of pregnant women are infected. Maternal CMV infection usually presents with few, if any, side effects. When first infected, some people may have symptoms similar to mononucleosis (i.e., fatigue, weakness, fever, lymphadenopathy). Most people in the United States are infected during childhood or as adults if they work around children. Pregnant women who have not been infected with CMV in the past and become infected during pregnancy (i.e., a primary infection) are at particularly increased risk of fetal CMV infection. Of note, recurrent or reactivation CMV infection in women can also cause fetal CMV infection, although the likelihood and severity of fetal infection is lower and less severe than with primary maternal CMV infection. For pregnant women, the two most common exposures to CMV are through sexual contact and through contact with the urine of young children with CMV infection. Most CMV infections encountered in pregnant women are asymptomatic, even during the acute stage. Less than 5% of pregnant women with primary infection are reported to be symptomatic, and an even smaller percentage suffer from a mononucleosis syndrome

Prognosis The severity of disease and its manifestations are determined by the timing of infection and the affinity of nervous tissue to different CMV strains. A normal second-trimester scan does not exclude an abnormal ultrasound examination later in gestation.

SONOGRAPHY

FREQUENT FINDINGS

• Hepatic calcifications

• Splenic calcifications

• Hydrops

  • Pleural effusions

  • Ascites

  • Anasarca

  • Scalp edema

  • Placentomegaly

• Cardiomegaly

• Ventriculomegaly

LESS FREQUENT

• Central nervous system

  • Microcephaly

  • Periventricular echogenic halo, indicating white matter necrosis

  • Linear calcifications in the basal ganglia

  • Punctate cerebellar calcifications

  • Intraventricular hemorrhage

  • Porencephaly

  • Lissencephaly

  • Subependymal cysts

  • Microphthalmia

• Echogenic small bowel

• Hepatomegaly

• Splenomegaly

• Punctate calcifications

  • Pericardial

  • Placental

• Echogenic nephropathy

PREGNANCY MANAGEMENT

Investigations and Consultations Required Maternal blood serologic testing is helpful in delineating the acuity of CMV infection. Serologic testing for CMV may be considered for women who develop influenza-like illness or a viral hepatitis-like illness during pregnancy or following detection of sonographic findings suggestive of CMV infection. Maternal blood ought to be tested for CMV immunoglobulin (Ig) M, IgG, and IgG avidity. To ascertain if fetal infection has occurred, amniocentesis can be performed, with testing of amniotic fluid for CMV-specific polymerase chain reaction (PCR). Amniocentesis should be timed for at least 7 weeks after the presumed time of maternal infection and at 21 weeks or more of gestation. This interval is important because it takes 5 to 7 weeks ...