Clinical manifestations
Toxoplasmosis can be categorized, depending on the immune status of
the patient, into 4 groups (1, 2).
- Immunocompetent patients (children, adults, pregnant women) are
predominantly asymptomatic. However, 10%-20% of those patients may
develop cervical or occipital lymphadenopathy or a flu-like illness.
Generally, symptoms are self-limited and resolve within weeks to
months. Recent data have suggested an association between Toxoplasma
gondii infection and various psychiatric or neurologic syndromes such
as schizophrenia, Alzheimer syndrome, and even suicide (7, 8).
- Immunodeficient patients. The reactivation of chronic situations may
lead to life-threatening disease (1, 2). In these individuals, the
Central Nervous System (CNS) is affected the most, and includes
encephalitis, decrease of mental status, seizures, movement disorders
and other psychiatric findings. Toxoplasmosis in immunodeficient
patients can present as chorioretinitis, pneumonitis or involve
multiple organs, finally leading to acute respiratory failure,
myocarditis and hemodynamic abnormalities (1).
- Ocular toxoplasmosis constitutes an important cause of chorioretinitis
and may be the result of acquired or congenital infection (1, 2).
Patients who have been infected by vertical transmission can be
asymptomatic until the second and the third decade of life, when
lesions develop in the eyes (1). Chorioretinitis in those individuals
is more often bilateral (2).
- In congenital toxoplasmosis, as has been said, the severity of
clinical and ultrasonographic findings in congenitally infected
fetuses is inversely related to the gestational age at the time of
primary maternal infection. As a result, a first trimester maternal
infection usually leads to more severe manifestations (4, 5, 10).
Prenatal ultrasonographic findings include intracranial
calcifications, ventricular dilatation, hepatic enlargement, ascites,
and increased placental thickness (9). In some cases, spontaneous
abortion, prematurity, or stillbirth may occur (1, 2). In general,
congenital toxoplasmosis is characterized by a wide spectrum of
clinical manifestations, but in 70-90% of infected newborns it is
subclinical, although involvement of CNS is a hallmark (1).
Chorioretinitis, hydrocephalus and intracranial calcifications
constitute the so-called classic triad of congenital toxoplasmosis
(1). Other clinical manifestations include microcephaly, strabismus,
blindness, epilepsy, mental retardation, petechiae due to
thrombocytopenia, anemia, hepatosplenomegaly, jaundice, myocarditis,
pneumonitis and respiratory distress (9).