Congenital toxoplasmosis
From Ganfyd
Infection occurs by ingestion of soil contaminated with cat faeces, or of infected meat (only the cat supports the full life cycle). Infection in an adult is usually asymptomatic. Congenital infection only occurs if there the pregnant woman is newly infected, and the risk of transmission is strongly associated with the gestational age at the time of seroconversion. The later in pregnancy, the higher the risk.
Symptoms of congenital infection include:
- Chorioretinitis (always present, whereas rare in acquired infection)
- Intracranial calcification
- Hydrocephalus
- Microcephaly
- Hepatosplenomegaly, jaundice
But actually, most congenital infections will be asymptomatic.
Diagnosis
CSF often shows pleocytosis and/or high protein.
Tricky. Discuss with a reference lab. In the pregnant woman or Mum, IgM is not a reliable indicator of recent infection. In the baby, look for IgA and IgM, do Sabin Feldman dye test (IgG could be maternal so useless).
Treatment
Symptomatic cases who are untreated have a poor neurodevelopmental outcome. Asymptomatic cases who are untreated (missed) have a significantly reduced IQ (although the mean is still in the normal range), frequently have blindness, deafness and/or seizures.
Treatment consists of a year of oral pyrimethamine and sulphadiazine (folinic acid is given concurrently to prevent side effects). Prednisolone is added initially if there is chorioretinits, high CSF protein or jaundice. With this regime, the outcome is excellent - normal IQ, resolution of seizures etc. There are alternative regimens - Fansidar is popular in Europe because it is given twice weekly, but levels are less.
Poor prognostic factors are hydrocephalus at birth, high CSF protein, hydrocephalus not improved by shunting, diabetes insipidus, apnoeas.
