RESUMO
La toxoplasmosis congénita es la consecuencia de la transmisión fetal por vía transplacentaria de Toxoplasma gondii tras la primoinfección materna. El riesgo de infección fetal es bajo en infecciones en el primer trimestre y va aumentando con la edad gestacional, mientras que la gravedad de la infección disminuye con esta. El diagnóstico de infección materna se realiza mediante la demostración de seroconversión o ante la presencia de IgM positiva con anticuerpos IgG de baja avidez. Las gestantes con infección demostrada deben recibir espiramicina para intentar evitar su transmisión al feto. El diagnóstico de infección fetal se realiza mediante reacción en cadena de la polimerasa (PCR) en líquido amniótico obtenido a partir de la semana 18 de gestación. Si esta prueba resulta positiva, debe iniciarse tratamiento a la embarazada con pirimetamina, sulfadiazina y ácido folínico. La mayoría de los niños infectados nacen asintomáticos pero hasta el 80% desarrolla secuelas visuales o neurológicas durante su infancia y adolescencia. El diagnóstico neonatal es complicado porque los anticuerpos IgM e IgA y la PCR en sangre y líquido cefalorraquídeo pueden ser falsamente negativos. En estos casos, el diagnóstico puede realizarse mediante la constatación de un ascenso significativo de los anticuerpos IgG o la persistencia de los mismos después del año de vida. El tratamiento neonatal con pirimetamina y sulfadiazina disminuye la posibilidad de secuelas a largo plazo. La toxoplasmosis congénita es una enfermedad prevenible mediante el cribado pregestacional y la adopción de medidas de profilaxis primaria en las gestantes seronegativas (AU)
Congenital toxoplasmosis is the result of transplacental fetal infection by Toxoplasma gondii after the primary maternal infection. The severity of the disease depends on the gestational age at transmission. First trimester infections are more severe, but less frequent, than third trimester infections. Acute maternal infection is diagnosed by seroconversion or by the detection of IgM antibodies and a low IgG avidity test. In these cases, spiramycin should be initiated to prevent transmission to the fetus. For identification of fetal infection, polymerase chain reaction (PCR) testing of amniotic fluid after 18 weeks gestation should be performed. If fetal infection is confirmed, the mothers should be treated with pyrimethamine, sulfadiazine and folinic acid. Most infants infected in utero are born with no obvious signs of toxoplasmosis, but up to 80% developed learning and visual disabilities later in life. Neonatal diagnosis with IgM/IgA antibodies or blood/cerebrospinal fluid PCR may be difficult because false-negative results frequently occur. In these cases diagnosis is possible by demonstrating a rise in IgG titers during follow-up or by the detection of antibodies beyond one year of age. Early treatment with pyrimethamine and sulfadiazine may improve the ophthalmologic and neurological outcome. Congenital toxoplasmosis is a preventable disease. Pre-pregnancy screening and appropriate counseling regarding prevention measures in seronegative women may prevent fetal infection (AU)
Assuntos
Humanos , Toxoplasmose Congênita/diagnóstico , Toxoplasmose Congênita/tratamento farmacológico , Complicações Infecciosas na Gravidez/prevenção & controle , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Padrões de Prática Médica , Coriorretinite/prevenção & controleRESUMO
Congenital toxoplasmosis is the result of transplacental fetal infection by Toxoplasma gondii after the primary maternal infection. The severity of the disease depends on the gestational age at transmission. First trimester infections are more severe, but less frequent, than third trimester infections. Acute maternal infection is diagnosed by seroconversion or by the detection of IgM antibodies and a low IgG avidity test. In these cases, spiramycin should be initiated to prevent transmission to the fetus. For identification of fetal infection, polymerase chain reaction (PCR) testing of amniotic fluid after 18 weeks gestation should be performed. If fetal infection is confirmed, the mothers should be treated with pyrimethamine, sulfadiazine and folinic acid. Most infants infected in utero are born with no obvious signs of toxoplasmosis, but up to 80% developed learning and visual disabilities later in life. Neonatal diagnosis with IgM/IgA antibodies or blood/cerebrospinal fluid PCR may be difficult because false-negative results frequently occur. In these cases diagnosis is possible by demonstrating a rise in IgG titers during follow-up or by the detection of antibodies beyond one year of age. Early treatment with pyrimethamine and sulfadiazine may improve the ophthalmologic and neurological outcome. Congenital toxoplasmosis is a preventable disease. Pre-pregnancy screening and appropriate counseling regarding prevention measures in seronegative women may prevent fetal infection.
