A man who has a penile chancre appears in a hospital’s emergency service. The VDRL test is negative. The most appropriate course of action for the physician in charge would be to
**Core Concept**
The patient's presentation of a penile chancre, a painless genital ulcer, is highly suggestive of primary syphilis. The VDRL (Venereal Disease Research Laboratory) test is a non-treponemal test used for screening syphilis, but it may be negative in the early stages of the disease.
**Why the Correct Answer is Right**
The correct course of action would be to perform a confirmatory test for syphilis, such as the RPR (Rapid Plasma Reagin) or the Treponema pallidum particle agglutination assay (TPPA), which are also non-treponemal tests. However, since the VDRL test is negative, it is essential to perform a treponemal test, such as the TPHA (Treponema pallidum hemagglutination assay) or the FTA-ABS (Fluorescent Treponemal Antibody Absorption) test, to confirm the diagnosis of syphilis. This is because treponemal tests become positive early in the disease and remain positive for life, making them more specific than non-treponemal tests.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because repeating the VDRL test without a confirmatory test would not provide a definitive diagnosis.
**Option B:** This option is incorrect because starting antisyphilitic therapy without a confirmed diagnosis could lead to unnecessary treatment and potential side effects.
**Option C:** This option is incorrect because relying solely on clinical examination for diagnosis may lead to false negatives or false positives, and a confirmatory test is necessary to confirm the diagnosis.
**Clinical Pearl / High-Yield Fact**
In cases of suspected syphilis, it is essential to perform a confirmatory test, such as a treponemal test, to confirm the diagnosis, as non-treponemal tests like VDRL may be negative in the early stages of the disease.
**Correct Answer: D. Perform a confirmatory test for syphilis.**