Congenital toxoplasmosis

Definition

Congenital toxoplasmosis is a group of symptoms that occur when an unborn baby (fetus) is infected with the parasite Toxoplasma gondii.

Causes, incidence, and risk factors

The fetus can become infected with toxoplasmosis if the mother becomes infected with toxoplasmosis during the pregnancy. The infection may spread to the fetus during the pregnancy itself, or during labor or delivery.

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

Symptoms

Up to half of the fetuses who become infected with toxoplasmosis during the pregnancy ae born early (prematurely). Congenital toxoplasmosis can damage the baby's eyes, nervous system, skin, and ears.

Often, there are signs of infection in the baby at birth. However, newborns with milder infections may not have symptoms or problems for months or even years. If they are not treated, almost all develop problems (especially in the eyes) when they become adolescents.

Symptoms may include:

• Enlarged liver and spleen
• Diarrhea or vomiting
• Eye damage from inflammation of the retina or other parts of the eye
• Feeding problems
• Hearing loss
• Jaundice
• Low birth weight (intrauterine growth restriction)
• Skin rash (petechiae or ecchymosis) at birth

Brain and nervous system damage may be severe or very mild, and may include:

• Seizures
• Abnormal brain and nervous system (neurologic) function

Signs and tests

The physical examination may show signs of:

• Anemia
• Cerebral calcifications
• Chorioretinitis
• Larger head size (hydrocephalus)
• Swollen lymph nodes (lymphadenopathy)
• Macrocephaly or microcephaly

Signs and symptoms that occur late in the disease include:

• Hearing loss
• Mental retardation
• Seizures
• Neurological problems
• Visual impairment

Prenatal tests include:

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

Postnatal diagnosis:

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

Treatment

Spiramycin can treat infection in the pregnant mother.

Pyrimethamine and sulfadiazine can treat fetal infection (diagnosed during the pregnancy).

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 the severity of the congenital toxoplasmosis.

Complications

• Hydrocephalus
• Blindness or severe visual disability
• Severe mental retardation or other neurological problems

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 tested to find out 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.).

Cook meat until it is well done, and wash your hands after handling raw meat.

References

Remington JS, McLeod R, Thulliez P, Desmonts G. Toxoplasmosis. In: Remington JS. Infectious Diseases of the Fetus and Newborn Infant. 6th ed. Philadelphia, Pa: Saunders Elsevier; 2006: chap 31.