Properties

Pathogenesis

Clinical findings

Laboratory diagnosis

Treatment & Prevention

Treponema pallidum

Thin-walled, flexible, spiral rods.

Motile through undulation of axial filaments that lie under outer sheath.

Not been grown on bacteriologic medial or cell culture.

Visualized using dark ground illumination.

Induce nonspecific antibodies detected by flocculation of cardiolipids extracted from normal mammalian tissues.

Transmision:

- natural syphilis infections occur in man.

- organism is very sensitive to drying & is only transmitted by intimate contact.

- transmitted from spirochete-containing lesions of skin or mucous membranes of an infected person to another.

- from pregnant women to their fetuses.

Produce no toxins or enzymes.

Immunity to syphilis is incomplete.

Antibodies to organism do not stop progression of disease.

Primary syphilis:

- a painless ulcer (chancre) appears at site of inoculation in 2-10 weeks.

- accompanied by enlargement of local lymph lodes.

- often sited on the genitalia .

- other extragenital sites: mouth, lips, anal canal, finger.

- ulcer heals spontaneously, but spirochetes spread widely in tissues.

Secondary syphilis:

- 1-3 months later: secondary lesions appear as a maculopapular rash on palms & soles.

- moist papules on skin & mucous membranes.

- moist lesions on genitalia: condylomata lata.

- organ involvement: meningitis, nephritis, hepatitis.

- lesions are rich in spirochetes & are highly infectious.

- heal spontaneously.

- these stages may be symptomatic, & yet disease may progress.

Latent syphilis:

- one-third of early syphilis progress to cure without treatment; another third remain latent.

- early stage: last a year or two after secondary stage, symptoms can reappear & patients can infect others.

- late stage: can last many years, no symptoms occur & patients are not infectious.

Tertiary syphilis:

- meningovascular syphilis: presents as a stroke after a period of other CNS disease (headache, vertigo, psychological abnormalities).

- tabes dorsalis: disease of dorsal columns of spinal cords; patient develops an ataxic gait, lightning pains & Aryll Robertson pupils (small irregular pupils which react to accommodation but not to light).

- gummatous syphilis: granulomatous lesions which become necrotic, leading to gumma; may affect skin or mucous membranes, leading to chronic ulcers.

- cardiovascular syphilis: aortitis of thoracic aorta, leading to narrowing of coronary arteries, aortic incompetence & aortic aneurysms.

Congenital syphilis:

- infection occurs during third month of pregnancy.

- organism cross placenta & may cause abortion.

- stillbirth or multiple fetal abnormalities may occur.

Nontreponenal tests:

- VDRL

- non-specific.

- use of nontreponemal antigens, e.g. cardiolipid

- titre fluctuates with intensity of disease; progressively falls with successful treatment.

- false-positive reactions in infections such as leprosy, hepatitis B & infectious mononucleosis.

Treponemal antibody tests:

- TPHA/FTA-abs

- more specific.

- lower false positive results.

- antibodies arise after 2-3 weeks of infection & so tests are positive in most patients with primary syphilis.

- stay raised for a very long time, even after successful treatment; may be negative in late untreated syphilis.

Antibiotic:

- penicillin

- tetrycycline

- erythromycin

Jarish-Herxheimer reaction:

- in patients treated with penicillin.

- fever, chills, myalgias a few hours after receiving antibiotic.

- due to lysis of treponemes with release of endotoxin-like substances.

- may last up to 24 hours.

- symptomatic relief with aspirin.

Prevention:

- antenatal screening.

- use of condoms.

- administration of antibiotic after suspected exposure.

- screen blood for transfusion.

No vaccine available.

Nonvenereal Treponematoses

None have been grown on bacteriologic media.

Transmitted by direct contact.

Bejel

Yaws

Pinta

Infections result in positive serologic tests for syphilis.

Penicillin