receive inadequate prenatal care. Transmission by the infected birth canal during delivery is not typical.

The pathogenesis of syphilis is complex and poorly understood. In immunocompetent patients, there is adequate systemic and local antibodies produced against several antigens; how the bacterium is able to persist despite high titers of circulating antibodies and an intact cellular immune response is not clear. Whatever the mechanism, small numbers of slowly dividing spirochetes survive in an immunocompetent patient [133].

19.5.5.2  Clinical Findings/Natural History

Ocular syphilis has been called “the great imitator” and “the great masquerader” because it often presents similarly to other ocular inflammatory conditions. Following transplacental infection of the unborn child, congenital syphilis is classified into early (presenting before 2 years of age) and late stages that roughly correspond to the secondary and tertiary stages of acquired syphilis. Systemic signs in early congenital syphilis include low birth weight, hepatosplenomegaly, thrombocytopenia, severe anemia, pneumonia, mucocutaneous lesions and osteochondritis. Late systemic manifestations include Hutchinson teeth, Mulberry molars, and abnormal facies with frontal bossing, progressive cranial nerve deafness, saddle-nose deformity, hypertelorism, rhagades, and saber shins [133].

Ocular lesions in early congenital syphilis are analogous to those found in acquired secondary syphilis. Mucous patches can appear on the conjunctiva, and there can be an acute iritis. The most common posterior segment changes include a multifocal chorioretinitis, and less commonly, a retinal vasculitis. As a result, nonprogressive hypoand hyperpigmented (“salt-and-pep- per” fundus) pigmentary mottling can be present with limited or diffuse involvement, and may be associated with normal vision. There can be attenuated retinal blood vessels [137–139].

The ocular manifestations of late congenital syphilis are diverse. Nonulcerative stromal keratitis is the most common inflammatory sign of untreated late congenital syphilis, appearing in 20–50% of cases, most commonly in girls [137]. Involvement is usually bilateral, and it is often accompanied by anterior uveitis. Bilateral secondary degeneration of the retinal pigment epithelium, along with secondary optic atrophy and narrowing of the retinal blood vessels, can present

a clinical picture that mimics retinitis pigmentosa. A retinal vasculitis with perivascular sheathing can also be present. Optic neuritis, cranial nerve palsies, and various pupillary abnormalities are late neuro-ophthal- mic sequelae [137–139].

Genetics

There does not appear to be any genetic influence that alters human susceptibility to syphilis.

Diagnosis/Treatment/Complications

The diagnosis of congenital syphilis is suspected by clinical presentation, with serology playing a primary role in confirming the diagnosis. Many cases of maternal syphilis are detected with routine prenatal screening. To diagnose a confirmed case of congenital syphilis, T. pallidum needs to be identified by dark-field microscopy, fluorescent antibody, or other specific stains in specimens from cutaneous lesions, placenta, or umbilical cord of an infected infant. As a result of passive transfer of immunoglobulin across the placenta, the infant born with congenital syphilis will have both positive nontreponemal (ex. Venereal Disease Research Laboratory (VDRL)) and treponemal antigen tests (ex. fluorescent treponemal antibody absorption (FTAABS) assay). Since IgM antibody does not cross the placenta, its presence indicates infection originating with the infant; thus, serodiagnosis of congenital syphilis is made using the IgM FTA-ABS [136, 139].

The principal goals of treatment are to eliminate the infectious spirochetes, and prevent or halt the progressive immune and structural damage. The recommended treatment for congenital syphilis in infants is crystalline penicillin G 50,000 units/kg given intravenously every 12 h for the first 7 days, and then every 8 h thereafter for a total of 10–14 days of therapy. Alternative therapy consists of procaine penicillin G 50,000 units/kg/day given as a single dose by intramuscular injection for 10 days. There are no proven alternatives to penicillin for the treatment of congenital syphilis [136, 137].

Complications from congenital syphilis include permanent visual loss from postinflammatory changes of the posterior segment of the eye, such as retinal ischemia, optic atrophy, macular pigmentary atrophy, and epiretinal membrane. Additionally, glaucoma or a secondary cataract may occur [140].