Gram Negative Spiral
Neeraj is 30-yrs-old comes to you with a two-week history of a penile ulcer. He noted that this ulcer did no hurt. Which one of the following conclusions/actions is most valid?
|A||Draw blood for a herpes antibody test|
|B||Even if treated, the lesion will remain for months|
|C||Failure to treat the patient will have no untoward effect, as this is a self-limiting infection|
|D||Perform a dark-field examination of the lesion|
a. This patient appears to have primary syphilis, as evidenced by a penile chancre that was not tender. One of the differences between syphilis and herpes simplex virus (HSV) is that an HSV lesion is excruciatingly painful.
b. Treponemal organisms may be seen microscopically in the lesion if the lesion is scraped. If not treated, the chancre will disappear and the patient will be asymptomatic until he/she exhibits the signs/symptoms of secondary syphilis, which include a disseminated rash and systemic involvement such as meningitis, hepatitis, or nephritis.
c. There are two kinds of tests for the detection of syphilis antibodies: non specific tests such as the RPR and VDRL, and specific tests such as the FTA, TPHA (T. pallidum hemagglutination test), and the MHTP (micro hemagglutination—T pallidum).
d. The difference is that the nonspecific tests use a cross-reactive antigen known as cardiolipin, while the specific tests use a T. pallidum antigen.
e. Although the nonspecific tests are sensitive, they lack specificity and often cross-react in patients who have measles, hepatitis, or infectious mononucleosis, or who are pregnant.
f. Some patients, especially those with autoimmune diseases, will have both non specific (RPR) and specific tests (TPA) positive even if they do not have syphilis.
g. Resolution of such a situation can be done by molecular methods for T. pallidum, such as PCR, or by the immobilization test using live spirochetes and the patient’s serum.
h. In the TPI test, the spirochetes will die in the presence of specific antibody.
i. Venereal Disease Research laboratory is situated in New York.
j. Antigen used is VDRL is cardiolipin antigen.
k. TRUST (Toluidine Red Unheated Serum Test) – It is a modification of RPR test and has an additional advantage in hot climates as the antigen is more stable than RPR antigen on storage at room temperature.
l. TPHA index (CSF albumin concentration X 103 / serum albumin concentration) and method for the demonstration of specific IgM antibodies in CSF are indicators of active neuro syphilis.