Description

Cytomegalovirus (CMV) is a ubiquitous double-stranded DNA virus that is a member of the herpesvirus family. It establishes latency in peripheral blood mononuclear cells and endothelial cells.

Epidemiology

• Primary infection occurs from early childhood into adolescence and childbearing years.
• Transmission occurs by contact with infected body fluids such as saliva, urine, blood, or breast milk through sexual contact or solid organ transplantation. Intrauterine transmission is the most common route of acquiring congenital infection.

General Prevention

• Pregnant women should receive education about CMV transmission. Precautions should be instituted for hospitalized patients known to be shedding CMV.
• Seriously ill neonates should receive blood products from CMV-negative donors.
• CMV-seronegative solid organ transplantation recipients should receive organs (and all blood products) from CMV-negative donors whenever possible.
• Hyperimmunoglobulin has been used in high-risk CMV-negative recipients of CMV-positive donors to prevent severe CMV disease.

Pathophysiology

Infection leads to intranuclear inclusions with massive enlargement of cells. Almost any organ may become infected with CMV in severe disseminated infection.

Commonly Associated Conditions

• Congenital infection
  • Occurs in about 1% of newborns in United States
  • Intrauterine transmission is more common in pregnant women mothers with primary infection during pregnancy (40–50%) compared to recurrent infection (<1%).
  • Postnatal acquisition of CMV via breast milk: Controversy exists over whether this precludes breastfeeding in premature infants (has a lower risk for neurologic sequelae than congenital infection).
  • 10% of infected infants are symptomatic at birth, with severe disease characterized by growth retardation, hepatosplenomegaly, thrombocytopenia, and central nervous system (CNS) involvement.
  • 10–20% of infants who are asymptomatically infected at birth may develop sensorineural hearing loss.
  • Of symptomatically infected infants, 90% will have some neurologic sequelae. Degree of impairments may be predicted by CT findings and microcephaly at birth.
• Mononucleosis syndrome
  • Syndrome similar to that caused by Epstein-Barr virus (EBV) infection in immunocompetent patients
  • The most common symptoms are malaise (67%) and fever (50%). ~70% of patients have abnormal liver enzymes.
  • Pharyngitis and splenomegaly less common and severe than observed with EBV-induced mononucleosis
• Interstitial pneumonitis
  • Seen primarily in severely immunosuppressed children and adults
  • Begins with fever and nonproductive cough but may progress to dyspnea and severe hypoxia over 1 to 2 weeks
  • Mild, self-limited pneumonitis may occur in immunocompetent patients.
• Retinitis
  • Observed in infants with symptomatic congenital infection and in patients with advanced AIDS
  • Immunosuppressed children should have regular eye exams.
• Hepatitis
  • Occurs in healthy individuals with primary infections and in immunosuppressed patients with either primary or reactivated disease
  • Fever, mild elevation of liver enzymes, and hepatomegaly are typical. Jaundice and severe hepatitis are uncommon.
• Gastrointestinal (GI) disease
  • Severely immunosuppressed patients may experience esophagitis, gastritis, colitis, or pancreatitis.
  • Diagnosis requires endoscopy with biopsy.
• CNS disease
  • Commonly seen in infants with symptomatic congenital infection
  • Characterized by microcephaly, periventricular calcifications, seizures, developmental delay, and sensorineural hearing loss
  • Encephalitis or meningoencephalitis may occur in immunocompromised patients and very rarely reported in literature in immunocompetent hosts.
• Hearing loss
  • Congenital CMV is the most common infectious cause of deafness.
  • Onset of deafness often seen after 1st month of life and is progressive; may be missed by newborn hearing screen (if only done in first 2 weeks of life)