Syphilis

Syphilis is one the sexually transmitted diseases effecting both man and women. In United States, 9,756 cases of primary and secondary syphilis are reported in the year 2006. Out of 9,756 total reported cases 8,297 were males and 1,459 were females. Reported cases of congenital syphilis in newborns are 349 cases in 2006. The signs and symptoms are difficult to distinguish between other diseases hence syphilis is called “great imitator”.

Causative Organism & features:

  • Organism: Treponema pallidum.
  • Obligate pathogen but not intracellular.
  • It has not been cultured in clinical lab; diagnosis is by serological test.
  • It is feebly refractile, basically a gram negative cell envelope

Reservoir
Human genital tract

High incidence: In 2006, the rate of Primary & Secondary syphilis was highest among women in the 20-24 year-old age group (2.9 cases per 100,000 population) and among men in the 35-39 year-old age group (13.5 cases per 100,000 population.

Incubation period: 10 to 90 days and the average is around 21 days.

Risk factors/Rout of transmission

  • Syphilis is transmitted through direct contact with syphilis sore.
  • Unprotected sexual intercourse
  • Any kind of sexual contact: oral, anal sex or vaginal
  • Baby born to infected mother: across the placenta.

Symptoms and Signs

  1. Congenital syphilis:

    Syphilitic pregnant women can transmit the disease across the placenta to the fetus. The infected fetus if born live develops congenital syphilis. The fetus presents with Hutchinson’s teeth, saddle nose or central nervous system anomalies.

  2. Acquired syphilis:
    The syphilis acquired through sexual contact. The organism enters through abrasions on the skin or mucosa of genitalia. Most of the patients are asymptomatic but they are highly infectious, especially during secondary lesion.
    The natural history falls in three stages in untreated patients: primary, secondary and tertiary lesions.chancre on the penis

    Primary lesions (primary syphilis):
    Painless, nontender, avascular circumscribed, ulcerated lesion called hard chancre develops at the site of inoculation. The margin of the ulcer is clean and with distinctly indurated edges. The chancre is covered by thick exudate which is a good source of material for microscopy as it contains Treponema Pallidum. Regional lymph nodes are enlarged. The lymph nodes are nontender and rubbery in consistency. The primary lesions heal spontaneously by leaving a scar in 3 to 6 weeks without treatment. However, if proper treatment is not given patient may develop secondary lesion.

    secondary syphilis

    Secondary lesions (secondary syphilis):
    It occurs 1 to 6 months after primary lesions. The secondary lesion is characterized by maculopapular rashes on the skin inculuding palms and soles. The rashes appear as rough, red, or reddish brown spots but may appear differently mimicking other diseases. The mucousal patches in the oropharynx, patchy hair loss and flat wart like condylomata at mucocutaneous junctions (eg; perianal) can be noticed. In untreated case disease may heal spontaneously in 25 percent of the patients or progress to latent stage in 25 percent of the patients or it can develop tertiary syphilis in rest 50 percent of the patients. In latent syphilis, the patients are asymptomatic but positive for serological test.

    Tertiary lesions (tertiary syphilis or late syphilis):
    It develops after a latent period of 1 to 30 years. The lesions consist of gummas, aneurysm, aortitis or CNS manifestations.

Differential diagnosis
Chancroid
Herpes simplex
Genital warts

Lab works

  • Darkfield examinations and direct fluorescent antibody (DFA) tests of lesion exudate or tissue are the definitive methods for diagnosing early syphilis.
  • A presumptive diagnosis
    1) nontreponemal tests (e.g., Venereal Disease Research Laboratory [VDRL] ) and
    2) treponemal tests (e.g., fluorescent treponemal antibody absorbed [FTA-ABS] and T. pallidum particle agglutination [TP-PA]).

Treatment

Recommended Regimen for primary, secondary and early latent syphilis in adults

  • Benzathine penicillin G 2.4 million units IM in a single dose

Recommended Regimens for Late Latent Syphilis in adults

  • Benzathine penicillin G 7.2 million units total, administered as 3 doses of 2.4 million units IM each at 1-week intervals