Thursday, June 23, 2011

Neonatal infections - Congenital rubella

The consequence of infection with rubella is congenital rubella syndrome can occur when rubella is transmitted in utero during maternal primary infection.When infection occurs in the first 11 weeks of pregnancy, babies presents heart defects and deafness, and between weeks 13 to 16 only deafness. When infection occurs after 16 weeks, babies do not have any congenital defect. So fetal pathology is common when infection occurs in the first 16 weeks of pregnancy.Pathogenic mechanisms induced teratogenic effect of rubella are not well known, the most common hypothesis is to suggest direct involvement of viral replication in cell clones during fetal organogenesis.
Clinical signs:
Rubella virus may infect one or all fetal organs and persist for a long time, so congenital rubella should be considered a chronic disease with a wide spectrum of clinical manifestations of dead newborn infant with multiple birth defects or apparently healthy infant.Clinical manifestations are grouped into three categories:- Transients: Thrombocytopenia, hepatitis;- Permanent structural defects: Cataracts;- Defects occur in time: deafness, Dia bet mellitus (DM).During neonatal infection may occur without clinical signs and they do not notice earlier than 2 months of life.
Congenital rubella syndrome is the classical one triad consists of: cataracts, deafness and heart defects.Cataracts and microphthalmia in 1 / 3 of cases.Sensory or central deafness is the most common sequel, occurs at a rate of 80% of infected children. It is the only event that can occur as isolated congenital rubella.
Clinical signs at birth are: IUGR, splenomegaly, thrombocytopenia, signs of meningoencephalitis, signs of interstitial pneumonia, lymphadenopathy, radiolucent bone.Meningoencephalitis occurs in 10-20% of cases, can cause mental retardation and motor and can present as a chronic progressive encephalitis.
Chronic disorders in development are:- Endocrinopathies: insulno-dependent diabetes mellitus (IDDM);- Worsening or sudden hearing defects;- Glaucoma;- Hypertension (HTA) with renal artery stenosis secondary or aorta;- Progressive mental retardation;- Conduct disorder.In addition to congenital infection syndromes mother near term is commonly associated with fatal neonatal disease, possibly due to fetal exposure to maternal antibodies in the absence of transplacental viremia protectors.
Positive diagnosis:
The diagnosis of congenital rubella must for any newborn suspected of proven or suspected mother with rubella during pregnancy or any child with IUGR or other stigmata of congenital rubella.Virus isolation is from: nasofaringe, conjunctival secretions, urine, CSF, blood.
Serological diagnosis can be obtained by monitoring IgG.Persistence of specific IgG increased in strength from 6-12 months of life is probable evidence of intrauterine infection. Diagnosis by specific IgM antibodies is doubtful.
Treatment:
Prophylactic treatment provides rubella vaccination, it protects children from measles and eliminating the risk of primary infection in childhood.It requires that vaccination fertile women who did not have rubella during childhood. Passive immunization with immunoglobulins does not guarantee fetal safety.
There is no effective therapy for congenital rubella virus. These children require recovery efforts, continuous monitoring of hearing defects and other defects that may occur as a result of intrauterine infection.Isolation newborn should be instituted as soon as infection was suspected.Children with congenital rubella should be considered contagious during the first year of life, except those who have negative cultures (cultures that are rarely negative before 3-6 months).

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