The precise times of placental and fetal invasion are unknown, but presumably they occur late in the gestational period. The clinical syndrome usually becomes manifest in the first days and weeks of postnatal life, when seizures, impaired alertness, hypotonia, weakness of the extremities, progressive hydrocephalus, and chorioretinitis appear. The retinal lesions consist of large pale areas of destroyed retina surrounded by deposits of pigment. If the infection is severe, the maculae are destroyed; optic atrophy and microphthalmos follow. We have several times observed hemiplegias in older infants, first on one side and then on the other, followed by tension hydrocephalus. The latter is present in about one-third of the cases.
The CSF contains a moderate number of white blood cells, mostly lymphocytes and mononuclear cells, and the protein content is in the range of 100 to 400 mg/dL (i.e., a higher protein content than all other neonatal infections except bacterial meningitis). The glucose values are normal. Fewer than 10 percent of infected children recover; the others are developmentally delayed to varying degrees, with seizures and paralysis. In those without symptoms of infection at birth, the outcome is better.
Granulomatous masses and zones of inflammatory necrosis abut the ependyma and meninges. The organisms, 6 to 7 mm in length and 2 to 4 mm in width, are visible in and near the lesions. Microcysts may also be found, lying free in the tissues without surrounding inflammatory reaction. The necrotic lesions calcify rapidly and, after several weeks or months, are readily visible in plain films of the skull. These appear in periventricular and other regions of the brain as multiple nodular densities (see Fig. 37-16).
In adults, often in association with HIV, the disease takes the form of a rapidly evolving meningitis and multifocal encephalitis in conjunction with myocarditis, hepatitis, and polymyositis.
This syndrome is described in Chap. 31, as are the diagnostic tests and current treatment. In the infant, infections such as rubella, syphilis, CMV disease, and herpes simplex must be considered in the differential diagnosis. The most reliable means of diagnosis is the IgM indirect fluorescent antibody test, performed on umbilical cord blood. Passive transfer of IgG antibody from mother to fetus takes place, but its presence in the fetus is not proof of active infection.
In women who develop antibodies in the first 2 or 3 months of pregnancy, treatment with spiramycin (Rovamycine) prevents fetal infection. Once the fetus is infected, pyrimethamine and sulfadiazine must be used. A later second pregnancy is not affected.
The clinical syndromes and pathologic reactions of congenital neurosyphilis of the newborn are similar to those of the adult, as described in Chap. 31. Such differences that exist are determined principally by the immaturity of the nervous system at the time of spirochetal invasion. The syphilitic infection may be transmitted to the fetus at any time from the fourth to the seventh months. The fetus may die, with resulting miscarriage or stillbirth, or may survive only to be born with florid manifestations of secondary syphilis. The dissemination of the spirochetes throughout the body, the time of appearance of the secondary manifestations, and the time of formation of antisyphilitic antibodies (reagin) in the blood are all governed by the same biologic principles that apply to adult syphilis.