CAUSATIVE ORGANISM:
Cytomegalovirus (CMV) or herpesvirus type 5(HHV-5). Family: Herpesviridae
TRANSMISSION:
CMV is transmitted through exposure to bodily fluids. Such as Urine, Feces, Blood, Semen, Urogenital secretions, Breast milk, urine. Vertical (Transplacental), Blood Transfusion, Organ Transplant.
RISK FACTORS:
Higher socioeconomic class (less likely to have immunity through childhood infection), immunosuppression (e.g. HIV).
EPIDEMIOLOGY:
CMV is ubiquitous, 50% adults develop immunity in pregnant women. 1% of seronegative pregnant women will contract CMV antenatally.
CLINICAL FINDINGS and COMPLICATIONS:
o Congenital- 90% infected infants appear normal, later 20% develop sensory nerve hearing loss, psychomotor mental retardation, or both. The infants with symptomatic illness (about 0.1% of all births) show congenital defects or disorders (jaundice, anemia, hepatosplenomegaly, thrombocytopenia, low birth weight, microcephaly, and chorioretinitis).
o Perinatal- Almost all of these perinatally infected infants have no discernible illness unless the baby is premature or immunocompromised. CMV can also be efficiently transmitted from mother to child by breast milk, but these postpartum infections are also usually benign.
o Post neonatal- CMV infections during childhood and adulthood are totally asymptomatic. CMV may cause a mononucleosis-like syndrome.
o Adults: Persons having AIDS, latent CMV may be reactivated and cause very serious disease. interstitial pneumonia (90% mortality), chorioretinitis, gastroenteritis, neurologic and other organs involvements.
SIGNS:
Often no clinical signs, may find lymphadenopathy.
PATHOLOGY/PATHOGENESIS:
Incubation period 1–2 months.
Cytomegalovirus infects epithelial cells and leukocytes. In vitro, CMV DNA can be demonstrated in monocytes showing no cytopathology, indicating a restricted growth potential in these cells. In addition to nuclear inclusions (“owl eye cells”), CMV produces perinuclear cytoplasmic inclusions and enlargement of the cell (cytomegaly), a property which gives the virus its name. Following primary infection can remain dormant and then reactivate (e.g. in immunosuppression).
INVESTIGATIONS
Bloods: CMV IgM (current infection)/IgG (immunity).
USS: Fetal anomaly scan.
Other: Amniocentesis for CMV PCR (6–9 weeks after primary infection).
MANAGEMENT:
No treatment to prevent transmission to fetus. May offer termination of pregnancy if evidence of CNS damage. Ganciclovir, a nucleoside analog of acyclovir (INN: Aciclovir), inhibits CMV replication and reduces the severity of CMV syndromes, such as retinitis and gastrointestinal disease. When given with hyper immune globulin, ganciclovir is thought to reduce the mortality. Neonatal gancyclovir can attenuate audiological complications.
PROGNOSIS:
Rate of transmission to the fetus is 40%. Of these, only 10% will develop the congenital Syndrome. Ninety percent of babies who are symptomatic at birth will have later neuro-developmental problems.
