Syphilis

– A contagious, sexually transmitted systemic disease characterized by sequential clinical stages with intervening years of symptomless latency.

Causes and Incidence

Syphilis is caused by the Treponema pallidum spirochete. The primary mode of transmission is sexual contact, although the disease may be transmitted transplacentally from an infected mother to her fetus. Syphilis is transmissible by blood in the incubation period and through intimate sexual contact in the primary and secondary stages. It occurs worldwide and is on the increase, particularly in women and neonates. The peak incidence occurs among males 15 to 30 years of age with multiple sex partners. More than 135,000 cases are reported each year in the United States. There is a striking relationship between syphilis and HIV-positive individuals; one fourth of the syphilitic population in some urban clinics also have HIV.

Disease Process

Syphilis occurs in five distinct stages: incubation, primary, secondary, latency, and late. Incubation lasts 10 days to 10 weeks and begins with penetration of a mucous membrane by T. pallidum. Some spirochetes remain at the site, whereas others migrate to regional lymph nodes and then systemwide to all organ systems. The inflammatory response in the endothelial tissue produces perivascular infiltration of lymphocytes and plasma cells, causing edema of the endothelium and endarteritis in the capillaries and terminal arterioles. Vessels thicken as fibroblasts proliferate and cause fibrosis and necrosis. The primary stage is marked by the appearance of a single lesion (chancre) at the site of infection. Serum infiltration and accumulation in the associated connective tissue produce a firm, hard lesion. The lesion heals spontaneously in 1 to 5 weeks. Satellite lesions may form in adjacent tissue or in regional lymph nodes. Nodes are swollen and nontender. The secondary stage begins as the primary stage disappears and generally lasts 2 to 6 weeks. Parenchymal, systemic, and mucocutaneous processes occur throughout the body. After the second stage a 1- to 40-year latency period ensues, followed by the late stage, in which the cardiovascular and nervous systems degenerate.

Symptoms

The disease can appear at any stage without manifestations from the previous stages.

Incubation
Asymptomatic; report of sexual contact with infected partner

Primary
Single lesion starting as a red papule and eroding into a painless ulcer that exudes a clear fluid; red areola around lesion; common sites include penis, anus, rectum, vulva, cervix, perineum, lips, tongue, buccal mucosa, and tonsils; swollen regional lymph nodes

Secondary
Symmetric, pale red (in whites) or pigmented (in blacks) macules, papules, or pustules that predominate on flexor and volar body surfaces, particularly the palms and the soles of the feet; grayish white erosive patches on mucous membranes; patchy hair loss; generalized swelling of lymph nodes

Latency
May see early mucocutaneous relapse signs but seldom after first year; asymptomatic period that may last rest of individual’s lifetime or may move at any time to late stage

Late
Lesions (gummas) of skin, bone, viscera, heart, and nervous system; lesions are indolent, increase slowly in size, and resolve slowly to painless ulcerations that scar on healing; deep, boring pain in bones with lump over involved site; dilation of ascending aorta with aortic insufficiency; meningovascular signs (e.g., headache, dizziness, confusion, lassitude, insomnia, stiff neck, blurred vision, aphasia, hemiplegia); mental deterioration, dementia, delusions; locomotor ataxia; body tremors; urinary retention; impotence; joint degeneration

Potential Complications

Complications occur as a result of untreated disease; they include periostitis, Charcot’s arthropathy, aortic regurgitation or aneurysm, meningitis, and widespread damage to the central nervous system, resulting in paresis or dementia paralytica.

Diagnostic Tests

Serology
Positive Venereal Disease Research Laboratory, rapid plasma reagin, automated reagin, or reagin screen tests useful for screening in primary and secondary stages (many false positive results with these tests); tests for fluorescent treponemal antibody (absorbed) and T. pallidum agglutination and microhemagglutination done to confirm positive screening tests (they become reactive in the early primary stage and remain reactive in latestage disease)

Darkfield microscopy
Examination of exudate from lesion is positive for T. pallidum in primary and secondary stages

Treatments

Surgery
None.

Drugs
Antiinfective drugs to kill spirochete are effective at all stages.

General
Mandatory report to local health authority; tracking of all sexual contacts; refraining from sexual activity until examination of exudates is negative; instruction about sexually transmitted diseases and the importance of completing the full antibiotic course and of returning for all follow-up examinations.