Setting: ambulatory clinic
CC: “I have a sore on my penis.”
VS: normal
HPI: A 34-year-old man with an ulcer on his penis for the past several days comes to the walk-in clinic. He had a raised papule a few days ago that started to ulcerate after 2 days. He has never had a lesion like this before, although he has had herpes simplex vesicles in the past. The lesion is not painful. He was on vacation 3 weeks ago and had multiple unprotected sexual encounters with other men.
PMHX:
Herpes simplex
HIV negative
Medications: none
PE:
Genital: There is a 2-cm lesion on the shaft of the penis with raised, indurated edges. There is nontender inguinal adenopathy present and no vesicles.
Initial Orders:
Darkfield microscopy
VDRL or RPR
Darkfield microscopy is the most accurate test for primary syphilis.
• Spirochetes are mobile when seen (Figure 10-6)
Figure 10-6. Microscopic view of Treponema pallidum. With darkfield microscopy, spirochetes appear as motile, bright corkscrews against a black background. (Reproduced with permission from Cox D, Liu H, Moreland AA, et al. Syphilis. In Morse S, Ballard RC, Holmes KK, et al., eds. Atlas of Sexually Transmitted Diseases, 3rd ed. Edinburgh: Mosby; 2003.)
Treponema pallidum
• Never cultured
• Spiral gram-negative
• Spirochete
VDRL and RPR
• They are nontreponemal tests.
• They detect anticardiolipin antibodies.
• They are 75% to 80% sensitive in detecting primary syphilis.
Darkfield microscopy can be done on the spot in a person with a genital lesion. This test is more sensitive than the nontreponemal tests, the VDRL and RPR. Nontreponemal tests need time to become abnormal.
Report:
Darkfield microscopy: positive for mobile spirochetes
Darkfield microscopy is 100% specific.
In real life, most places do not use the darkfield examination. Only the RPR or VDRL is done initially, followed by specific treponemal tests such as the fluorescent treponemal antibody absorption (FTA-ABS) test. On CCS, however, you get to be an “idealist,” where every test you want is available.
What is the management of a penicillin-allergic patient with a chancre?
a. Desensitization to penicillin
b. Ceftriaxone IM
c. Doxycycline orally
d. Erythromycin
Answer c. Doxycycline orally
Oral doxycycline is more effective than erythromycin. Desensitization is not necessary for primary or secondary syphilis. Desensitization is performed in those with tertiary syphilis and those who are pregnant. Ceftriaxone is a less effective alternative to IV penicillin for tertiary syphilis.
Desensitization is not needed for genital lesions.
Doxycycline orally is enough.
Orders:
• Benzathine penicillin: one IM injection
Keep all patients given IM injections in the clinic for a few hours for observation postinjection. Move the clock forward at 1-hour intervals for 3 hours and do an Interval History.
Chancre
• It is the main manifestation of primary syphilis.
• They resolve spontaneously in 3 to 6 weeks.
• Twenty-five percent recur as secondary syphilis.
Interval History: (at 3 hours after IM penicillin)
Headache, myalgia, and rash develop (Jarisch-Herxheimer reaction)
Mechanism of Jarisch-Herxheimer Reaction
• Release of treponemal lipopolysaccharide
• Tumor necrosis factor alpha (TNF-alpha)
• Interleukin-6
Jarisch-Herxheimer reaction is not dangerous.
Orders:
Transfer patient to home.
Have patient use aspirin.
Have patient return in 1 to 2 days for follow-up.
The patient returns the following day.
Interval history: “Resolution of fever and myalgia”
Report:
VDRL or RPR: positive at 1:256
FTA positive
A single IM injection of penicillin is all that is needed for primary and most secondary syphilis. Bring the patient back at 3, 6, and 12 months. Recheck the VDRL or RPR at each visit. There should be a marked reduction in the titer. The FTA will stay positive lifelong.