Syphilis is a reemerging multisystem, chronic bacterial infection caused by the spirochete Treponema pallidum. It is associated with numerous ocular manifestations in both the acquired and congenital forms of the disease. Transmission occurs most often through sexual contact; however, transplacental infection of the fetus is also possible, mainly after the tenth week of pregnancy. Having reached an all-time low in the year 2000 in the United States, the incidence rate of syphilis at any disease stage has been rising in the last 2 decades, not only in men, particularly those having sex with men, but also among women. This rise is associated with an almost twofold increase in the incidence of congenital syphilis in the United States (from 9.4 to 15.7 per 100,000 live births).
Although syphilis is thought to be responsible for less than 2% of all uveitis cases, it is one of the great masqueraders in medicine and should always be considered in the differential diagnosis of any intraocular inflammatory disease. It is one of the few entities that can be cured with appropriate antimicrobial therapy, even in patients with human immunodeficiency virus (HIV) coinfection. Delay in the diagnosis of syphilitic uveitis may lead not only to permanent vision loss but also to significant neurologic and cardiac morbidity, which may have been averted with early treatment.
The prevalence of congenital syphilis is increasing in the United States in parallel to higher rates of infection in young women, associated with limited to late or even absent prenatal care, without proper serologic screening. Primary or secondary syphilis in the mother is more likely to be transmitted to the baby than is latent syphilis; the longer the mother had syphilis, the less likely is the transmission. Systemic findings in patients with early congenital syphilis (age 2 years or younger) include hepatosplenomegaly, characteristic changes of the long bones on radiographic examination, abdominal distention, desquamative skin rash, low birth weight, pneumonia, and severe anemia. Late manifestations (age 3 years or older) result from scarring during early systemic disease. These include Hutchinson teeth, mulberry molars, abnormal facies, cranial nerve VIII deafness, bony changes such as saber shins and perforations of the hard palate, cutaneous lesions such as rhagades, and neurosyphilis. Cardiovascular complications are unusual in late congenital syphilis. For further discussion of ocular manifestations of congenital syphilis, see BCSC Section 6, Pediatric Ophthalmology and Strabismus.
Ocular inflammatory signs of congenital syphilis may present at birth or decades later and include uveitis, interstitial keratitis, optic neuritis, glaucoma, and congenital cataract. Multifocal chorioretinitis and, less commonly, retinal vasculitis are the most frequent uveitic manifestations of early congenital infection. They may result in a bilateral salt-and-pepper fundus, which affects the peripheral retina, posterior pole, or even a single quadrant. These changes are not progressive, and the patient may have normal vision. A less commonly described fundus finding is that of a bilateral secondary degeneration of the retinal pigment epithelium (RPE), which may mimic retinitis pigmentosa, with narrowing of the retinal and choroidal vessels, optic disc pallor with sharp margins, and morphologically variable deposits of pigment.
Nonulcerative stromal interstitial keratitis, often accompanied by anterior uveitis, is the most common inflammatory sign of untreated late congenital syphilis, occurring in up to 50% of cases, most commonly in girls (Fig 10-1). Intraocular inflammation in this setting is thought to be reactive to T pallidum in the cornea (keratouveitis). Symptoms include intense pain and photophobia. Blood vessels invade the cornea, and late stages show deep “ghost” (nonperfused) stromal vessels and corneal opacities. Left untreated, corneal inflammation may regress but leave the cornea focally or diffusely opaque, with reduced vision, even to the level of light perception only. Anterior uveitis accompanying interstitial keratitis may be difficult to observe because of corneal haze. Glaucoma may also occur. The constellation of interstitial keratitis, cranial nerve VIII deafness, and Hutchinson teeth is called the Hutchinson triad.
Figure 10-1 Active syphilitic interstitial keratitis.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.