Neonatal Problems: Congenital Toxoplasmosis

Description

Toxoplasmosis is an infection with the parasite Toxoplasma gondii . If a woman becomes infected during pregnancy the infection may pass through the placenta to the developing foetus. Women at risk of acute infection and secondary transmission to their foetus are those who are antibody-negative (were not previously exposed to T. gondii ) and whose culinary practices include the use of raw, previously unfrozen meat (e.g., some women of French or African descent, Inuit women) and women who travel to these regions during pregnancy, as well as women who handle kittens or previously uninfected cats and/or kitty litter during pregnancy.
Transplacental transmission following maternal infection may occur throughout pregnancy, although it is more common later in pregnancy. The severity of infection is inversely related to the gestational age at which transmission occurs.

Symptoms and Signs

Infection may result in symptomatic neonatal disease, either generalised or neurological; symptomatic disease occurring in the first months of life, usually neurological; sequelae or relapse later in childhood of a previously unrecognised infection, usually chorioretinitis; and subclinical infection. The vast majority of infants have subclinical infection. 40% of symptomatically infected infants show abnormalities in brain scans (e.g., computed tomography [CT] scan).

Diagnosis and Treatment

1. Maternal Infection. A positive antibody test in pregnancy is insufficient evidence of the need for therapy: 10% to 40% of pregnant women have toxoplasmosis-specific antibody due to remote infection, depending on culinary practices, exposure to cat excreta, country of birth, etc. Furthermore, toxoplasmosis-specific immunoglobulin (Ig) M antibody may persist for more than one year, and in these situations may well have anteceded any risk of foetal disease.
Once toxoplasmosis is diagnosed in the mother, treatment with spiramycin is recommended to prevent transplacental transmission of toxoplasmosis. While spiramycin is not teratogenic , it does not cross the placenta.

2. Foetal Infection . Infection of the foetus follows either symptomatic or asymptomatic infection in pregnancy. Women with a history of ingestion of raw meat in pregnancy, who travel to a region with high rates of infection (e.g., France) or who acquire a kitten and handle kitty litter should be tested.
When foetal infection is confirmed, generally after 20 weeks’ gestation, the combination of pyrimethamine, sulphadiazine and folinic acid is used.

3. Newborn Infection . The diagnosis of congenital toxoplasmosis in the newborn infant should be considered in the presence of positive maternal serology and/or suggestive clinical findings often associated with abnormalities of ophthalmological examination, cerebrospinal fluid analysis and cranial CT scan.
Management of congenital toxoplasmosis should be carried out in conjunction with a colleague experienced in this area. The treatment of choice for congenital toxoplasmosis in the neonate is the combination of pyrimethamine, sulphadiazine and folinic acid administered for one year. These children need to be followed carefully for evidence of myelosuppression secondary to medication, appearance or progression of retinal disease, development of ventricular obstruction and developmental delay. Multidisciplinary follow-up care, appropriate to the deficit and with attention to auditory function, is required. Breastfeeding by an infected mother provides no risk to her infant. These infected children are not contagious.

The information in this page is presented in summarised form and has been taken from the following source(s):
1. Canadian Paediatric Society: http://www.cps.ca/