Congenital toxoplasmosis

Definition

Congenital toxoplasmosis is a group of symptoms and characteristics caused by infection of the fetus with the organism Toxoplasma gondii.

Causes, incidence, and risk factors

Fetal infection with toxoplasmosis results when a nonimmune pregnant woman is initially infected with toxoplasmosis, or if she has a history of toxoplasmosis during previous pregnancies.

For the mother the disease is generally mild and may not be evident. Infection of the fetus, however, can cause severe problems. Infection early in pregnancy results in more severe problems than later infection.

Congenital toxoplasmosis is characterized by damage to the eyes, nervous system, skin, and ears. The newborn often has a low birth weight, enlarged liver and spleen, jaundice, anemia, petechiae (fine red dots in the skin caused by bleeding of the capillaries), and eye damage evidenced by inflammation of the retina.

Symptoms

• Prematurity
• Small birth weight infant
• Increased or prolonged jaundice
• Skin rash (petechiae or ecchymosis) at birth

Signs and tests

The physical examination may show signs of:

• Chorioretinitis
• Cerebral calcifications
• Hydrocephalus
• Macrocephaly or microcephaly
• Lymphadenopathy
• Anemia

Late manifestations (signs and symptoms that occur late in the disease) include:

• Seizures
• Mental retardation
• Various neurological manifestations
• Visual impairment
• Hearing loss

Prenatal tests include:

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

Postnatal diagnosis:

• CT scan
• Standard ophthalmic examination
• Neurological examinations
• Antibody studies on cord blood and cerebrospinal fluid
• TORCH screen

Treatment

Infection in the pregnant mother can be treated with spiramycin.

Fetal infection (diagnosed during the pregnancy) can be treated with pyrimethamine and sulfadiazine.

Treatment of infants  with congenital toxoplasmosis typically includes pyrimethamine, sulfadiazine, and leucovorin for one year. Infants are also sometimes given steroids if their vision is threatened or if the protein level in the spinal fluid is high.

Expectations (prognosis)

The outcome depends on severity of the congenital toxoplasmosis.

Complications

• Blindness or severe visual disability
• Severe mental retardation
• Other neurological manifestations

Calling your health care provider

Call for an appointment with your health care provider if you are pregnant and think you are at risk for toxoplasmosis (for example, if you have a cat and are the person who cleans the litter box).

Call for an appointment with your health care provider if you are pregnant and have not received any prenatal care.

Prevention

Prospective or expectant mothers can be serologically tested to determine if they are at risk for toxoplasmosis. Pregnant women who have cats as house pets may be at increased risk of developing toxoplasmosis.

They should avoid contact with any materials that are potentially infected with cat feces, or that could be contaminated by insects exposed to cat feces (cockroaches, flies, etc.). Meat should be cooked until well done, and hands should be washed after handling raw meat.

References

Cohen J, Powderly WG. Infectious Diseases. 2nd ed. New York, NY: Elsevier; 2004.

Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 6th ed. London: Churchill Livingstone; 2005.