Congenital rubella syndrome: symptoms, pathogenesis

Congenital rubella syndrome in the form of a triad of the most common developmental anomalies - cataracts, heart defects and deafness was first described by the Australian ophthalmologist Gregg (Greg's triad). Later, CNS lesions with mental retardation, microphthalmia, low birth weight, dermatitis, etc. were described. Some developmental defects caused by the rubella virus do not always manifest themselves at an early age; they can also occur later. Lesions of some organs in the first days of life are not always easy to diagnose. It is especially difficult to recognize developmental defects of the hearing organ, retinopathy, high myopia, congenital glaucoma. Developmental defects of the cardiovascular system are also not always possible to recognize in the first days of a child's life. Fetal brain damage by the rubella virus often leads to the development of chronic meningoencephalitis, but clinical manifestations in the newborn may be very weakly expressed in the form of drowsiness, lethargy or, conversely, increased excitability. Sometimes convulsions occur. In these cases, microcephaly is gradually revealed.

Early neonatal manifestations of congenital rubella include multiple hemorrhages accompanied by thrombocytopenia. The rash lasts 1-2 weeks, sometimes longer. There are hepatitis with jaundice, enlarged spleen, hemolytic anemia, interstitial pneumonia, damage to tubular bones (X-ray examination reveals areas of rarefaction and compaction of bones).

Less frequently observed are malformations of the skeleton and skull, genitourinary and digestive systems, etc. Developmental anomalies depend on the time of exposure of the fetus to the virus.

All children whose mothers had rubella in the first 8 weeks of pregnancy have some defects. When the disease occurs in subsequent periods, the frequency of anomalies is significantly reduced. However, the teratogenic effect of the virus manifests itself in the 4th and even 5th month of pregnancy. In addition, with rubella, pregnancy often ends in miscarriage or stillbirth.

Congenital rubella is a chronic infection with persistence of the virus from several months to 1 year or longer. Such children pose an epidemiological danger to others.

Pathogenesis of congenital rubella

The virus enters the fetus through the mother's bloodstream during the viremia period, which lasts 7-10 days before the rash appears and for some time during the rash period. It is assumed that the rubella virus affects the epithelium of the chorionic villi and the endothelium of the placental capillaries and from there, in the form of tiny emboli, is carried into the fetus's bloodstream and disseminates into the tissues. A chronic infection occurs, which causes the formation of congenital malformations.

Cytodestructive action is not characteristic of the rubella virus, it manifests itself only in the lens of the eye and the cochlea of the inner ear. The rubella virus inhibits local mitotic activity of cells, which leads to slow growth of cell populations that are unable to participate in differentiation and interfere with the proper development of the organ.

By affecting the embryo at different stages of gestation, the rubella virus causes different developmental defects depending on which organ is developing at a given period. It is important to determine the indications for termination of pregnancy in case of rubella in the first 3 months of pregnancy. If a pregnant woman comes into contact with a rubella patient, a repeated serological examination is necessary at intervals of 10-20 days to detect asymptomatic infection.

The use of immunoglobulin to prevent rubella in pregnant women is ineffective.

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