Congenital toxoplasmosis

Alternate names

Mother-to-child transmission of toxoplasmosis; Toxoplasma embryofetopathy; Toxoplasma embryopathy

Definition

Congenital toxoplasmosis (CTX) is an embryo-fetopathy characterized by ocular, visceral or intracranial lesions secondary to maternal primo-infection by Toxoplasma gondii (Tg). Congenital toxoplasmosis is a group of symptoms that occur when an unborn baby (fetus) is infected with the parasite Toxoplasma gondii.

Epidemiology

Given its infectious origin, incidence of CTX is variable over time and geographically. Screening policies and methods also influence prevalence calculation. A low estimate of the overall prevalence might be of 1:3,030 births, with symptomatic cases at 1:29,000 births.

Cause

• CTX is caused by the mother's primo-infection by Tg, an intracellular protozoan parasite of the Apicomplexa phylum, and transmission to the fetus by trans-placental infection.
• Nearly 25% of exposed fetuses are infected.
• Mother is infected by Tg through ingestion of ooccysts present in cat faeces and soil, or of cysts present in uncooked meat.

Signs and symptoms

• Clinical presentation is highly variable.
• Earlier infection is generally more severe but less frequent.
• Infections in the first trimester may result in miscarriage or fetal death in utero, whereas later ones may be limited to ocular anomalies.
• Intracranial calcifications, micro- or macrocephaly, ventricular dilatation and hydrocephalus, hepatomegaly, splenomegaly, cardiomegaly, ascites and intrauterine growth retardation can be observed in infected fetuses.
• When present, clinical manifestations at birth are maculopapular rash, jaundice, generalized lymphadenopathy, organomegaly, central nervous system anomalies and hyperbilirubinemia, anemia, and thrombocytopenia.
• The first neurologic manifestation is seizures; nystagmus, hypotonia and, later, delay of developmental milestones acquisition can be seen.
• The chorioretinitis - intracranial calcifications - hydrocephalus triad is present in 10% of cases.
• Ocular involvement may develop after months or years, most frequently with chorioretinitis, followed by microphthalmia and strabismus.
• Visual impairment is highly dependent on the parasite genotype, and probably on prenatal and postnatal treatments.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Abnormality of retinal pigmentation
• Premature birth(Premature delivery of affected infants)

5%-29% of people have these symptoms

• Anemia(Low number of red blood cells or hemoglobin)
• Ascites(Accumulation of fluid in the abdomen)
• Cardiomegaly(Enlarged heart)
• Cerebral calcification(Abnormal deposits of calcium in the brain)
• Cognitive impairment(Abnormality of cognition)
• Diarrhea(Watery stool)
• Elevated hepatic transaminase(High liver enzymes)
• Failure to thrive in infancy(Faltering weight in infancy)
• Global developmental delay
• Hearing impairment(Deafness)
• Hepatomegaly(Enlarged liver)
• Hydrocephalus(Too much cerebrospinal fluid in the brain)
• Intrauterine growth retardation(Prenatal growth deficiency)
• Jaundice(Yellow skin)
• Lymphadenopathy(Swollen lymph nodes)
• Macule(Flat, discolored area of skin)
• Microcephaly(Abnormally small skull)
• Microphthalmia(Abnormally small eyeball)
• Muscular hypotonia(Low or weak muscle tone)
• Nystagmus(Involuntary, rapid, rhythmic eye movements)
• Seizure
• Thrombocytopenia(Low platelet count)
• Ventriculomegaly
• Visual impairment(Impaired vision)

Diagnosis

The health care provider will examine the baby. The baby may have:

• Swollen spleen and liver
• Yellow skin (jaundice)
• Inflammation of the eyes
• Fluid on the brain (hydrocephalus)
• Swollen lymph nodes (lymphadenopathy)
• Large head size (macrocephaly) or smaller-than-normal head size (microcephaly)

Tests that may be done during pregnancy include:

• Amniotic fluid testing and fetal blood testing
• Antibody titer
• Ultrasound of the abdomen

After birth, the following tests may be done on the baby:

• Antibody studies on cord blood and cerebrospinal fluid
• CT scan of the brain
• MRI scan of the brain
• Neurological exams
• Standard eye exam
• Toxoplasmosis test

Treatment

In several countries, a systematic serological status follow-up of each pregnant woman is organized in order to diagnose and treat early maternal and fetal infections. Seronegative pregnant women are tested regularly to detect seroconversion, with, if needed, a spiramycin-based treatment, expected to reduce vertical transmission. A pyrimethamine-sulphonamide combination is recommended in case of confirmed fetal infection. Neonates should also be treated even if they are asymptomatic at birth since complications may occur later. The benefits of prenatal and postnatal treatment remain to be assessed.

Prognosis

Prognosis is highly dependent on the parasite genotype, the gestational age at maternal infection and on the timing of prenatal and postnatal treatment.

NIH genetic and rare disease info

• NIH info on Congenital toxoplasmosis

Congenital toxoplasmosis is a rare disease.

Congenital toxoplasmosis Resources
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