This man has tertiary syphilis, charactertized in this case by the presence of aortitis, tabes doralis and prior history of a maculopapular rash that covers the trunk, palms and soles. Agglutination of antibodies with beef cardiolipin would be diagnostic.
Syphilis, caused by Treponema pallidum, has three stages of disease. Primary syphilis presents with a painless chancre. Secondary syphilis presents one to two months later and is marked by a maculopapular rash. Roughly 33% of patients progress to tertiary syphilis, which is characterized by gummas, aortitis, tabes dorsalis and the presence of an Argyll Robertson pupil. The nonspecific screening test for syphilis is the VDRL, which is positive with agglutination when antibodies against beef cardiolipin are mixed with the patients serum. If positive, the confirmatory test is the more specific FTA-ABS.
Roett et al. review diagnostic tests for syphilis. They recommend serologic tests for syphilis and darkfield microscopy or direct fluorescent antibody testing for Treponema pallidum.
Dourmishev et al. review the stages and progression of syphilis. They report that tertiary syphilis occurs decades after infection in three main forms: gummatous, cardiovascular, and neurosyphilis (asymptomatic, meningeal, meningovascular, and parenchymatous-such as general paresis or tabes dorsalis).
Illustrations A and B depict the maculopapular rash associated with secondary syphilis. Illustration C shows a case of the gummatous form of tertiary syphilis. Illustration D demonstrates the effect of neurosyphilis on the posterior columns, a complication of tertiary syphilis called tabes dorsalis.
Answer 2: Indirect immunofluoresence of the patient’s serum and killed T. Palladium describes the FTA-ABS which is used after the VDRL to confirm syphilis.
Answer 3: Cytoplasmic inclusions on Giemsa stain would be expected with Chlamydiae, which can present with reactive arthritis.
Answer 4: Agglutination of patients serum with Proteus O antigens, or Weil-Felix reaction, detects Rickettsial infections with the exception of Coxiella.
Answer 5: Gram positive, oxidase positive, comma shaped bacteria growing at 42 degrees C describe Campylobacter jejuni, which can present with the ascending paralysis of Guillain-Barre, but not the cardiovascular or characteristic rash described above.
Roett MA, Mayor MT, Uduhiri KA. Diagnosis and management of genital ulcers. Am Fam Physician. 2012 Feb 1;85(3):254-62.
PMID:22335265 (Link to Abstract)
Dourmishev LA, Dourmishev AL. Syphilis: uncommon presentations in adults. Clin Dermatol. 2005 Nov-Dec;23(6):555-64.
PMID:16325063 (Link to Abstract)
USMLE World Step 1 QBank Question #1316. Copyright © USMLEWorld, LLC 2012