Background:
Syphilis is caused by an infection with a
spirochete, Treponema pallidum, a thin, tightly wound, relatively
stiff, spiral-shaped parasite measuring 10-13 mm.
Schaudinn and Hoffman of Hamburg discovered T pallidum in 1905.
This disease has been a source of social stigma, morbidity, and mortality for
centuries, and it was notably notorious in the early 1900s for infectious
chorioretinitis. The term "syphilis" came from a poem written in 1530 by the
Italian poet Hiero Fracastor. His main character, in the poem, was an infected
shepherd named Syphillus. Syphilis was first described at the end of the 15th
century by an Italian physician, Nicolaus Leonicenus, at the same time of the
return of the first European explorers from the New World. When Charles VIII of
France invaded Naples with mercenaries from all over Europe, spread of this
disease was noted on both war camps and was termed French Pox and Neopolitan
Pox, respectively.
Syphilis can be congenital or acquired. The acquired form usually is sexually
transmitted, chronic, and systemic. Although the introduction of penicillin in
the 1940s decreased the epidemiology, there has been a resurgence of the
disease, over the past two decades, especially among nonwhites, male
homosexuals, and intravenous drug users. Bacterial resistance, poor
socioeconomic backgrounds, increased high-risk sexual activity, and
immunodepressing diseases have contributed to this resurgence.
Syphilis has been given titles such as "the great imitator, the great mimic,
and the great masquerader!" of ocular inflammatory conditions. It lacks
pathognomonic signs and often presents similar to other ocular inflammatory
condition.
Syphilis is associated with the following ocular diseases: interstitial
keratitis, episcleritis, scleritis, iritis, iris papules, chorioretinitis,
papillitis, retinal vasculitis, and exudative retinal detachment.
Pathophysiology:
Primary syphilis
The predominant lesion of primary syphilis is a chancre at the inoculation
site, which usually is at the genitalia region. Chancres are erythematous
papules at the inoculation site that later erode to form painless ulcers. They
may occur at multiple sites. Spirochetes fill the serous fluid from these
lesions. The lesions appear 4 weeks after the initial infection and heal
spontaneously in 1-2 months.
After T pallidum penetrates the skin or mucous membrane, the
organism enters the lymphatics and blood stream and disseminates shortly after
contact. If left untreated, primary syphilis leads to secondary syphilis.
Secondary syphilis
The systemic treponemal load is largest in secondary syphilis. Generalized
maculopapular (or pustular rash), and lymphadenopathy are the characteristic
lesions in this stage. These lesions appear 4-10 weeks after the initial
manifestation. Lesions usually present at the flexor and volar body surfaces (ie,
palms, soles). Resolution occurs without scarring, although hyperpigmentation or
hypopigmentation may occur. Papules (condylomata lata) at the mucocutaneous
junctions, and in moist areas of the skin, appearing as dull pink or gray
hypertrophic lesions, are common.
Constitutional symptoms of fever, malaise, headache, nausea, anorexia, and
joint pains often are present. The liver, kidneys, and/or GI tract may or may
not be involved. Ocular involvement has been reported in 10% of cases, and
cerebrospinal fluid (CSF) pleocytosis has been seen in a few cases.
Latent syphilis
Latent syphilis follows secondary syphilis and is divided into 2 groups,
early latent and late latent. These subgroups occur within and beyond 1 year
after initial infection, respectively. Most cases have been reported to stay at
the latent stage with 30% converting to the next stage.
Tertiary syphilis
Tertiary syphilis is divided into 3 groups (ie, benign tertiary,
cardiovascular, neurosyphilis). Benign tertiary syphilis characteristically
presents with gummatous lesions that are actually granulomas, histologically, in
the skin and the mucous membranes. The lesions may occur in the choroid, ciliary
body, and iris. Cardiovascular syphilis presents with involvement of the
coronary arteries or the aorta. Neurosyphilis may manifest with tabes dorsalis
or general paresis. The CNS is affected via the vascular pathways or via direct
involvement of parenchyma.
Quaternary syphilis
Quaternary syphilis has been disregarded for some time now; however, with the
advent of AIDS-related syphilis cases, this stage is being reintroduced. Some
authors use it to describe an aggressive form of neurosyphilis, where there is
necrotizing encephalitis in patients with the acute immunodeficiency syndrome.
Frequency:
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In the US:
Occurrence is higher in southern and
southwestern US. It is higher in large urban populations.
In 1940, prior to the introduction of antibiotics, the incidence of primary
and secondary syphilis was about 100,000 cases. In 1956, with antibiotic
therapy, incidence declined steadily to 10,000 cases.
In the early 1980s, the incidence of syphilis rose to about 35,000. In
1988, 40,275 new cases of primary and secondary syphilis were reported.
In 1990, as a result of intravenous drug and crack cocaine abuse, as well
as illegal prostitution, the incidence went up to more than 45,000 cases.
In 1995, 16,500 cases were reported in the Summary of Notifiable Diseases.
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Internationally:
In Seville, Spain, a report indicates
that enhanced opportunity for spread accounts for clustering of syphilis in
some towns.
In Singapore, special political and sociologic factors, including
prostitution, reduced prescribing of penicillin for gonorrhea because of the
emergence of penicillin-resistant strains of Neisseria gonorrhoeae,
and loss of "herd" immunity, resulted in an increase of early infectious
syphilis from 1980-1984.
Mortality/Morbidity:
Morbidity from primary and secondary
syphilis ranges from the irritation brought about by the primary lesion to the
more significant symptoms of secondary syphilis.
Race: Incidence is greater among nonwhites.
Sex:
Age:
