Cardiovascular syphilis
Clinicians need to be aware of cardiovascular syphilis in patients at risk of infection, with the time taken from initial infection to clinical manifestation ranging from 10 to 25 years, although this is accelerated in patients with HIV infection. Inadequate or interrupted antibiotic therapy may confound the development of cardiovascular syphilis and make diagnosis difficult. In diagnosis, serological testing is the mainstay: latent or inadequately treated syphilis should be suspected with the finding of a positive non-specific treponemal serological test (e.g. rapid plasma reagin) and a positive specific treponemal antibody test (e.g. Treponema pallidum haemagglutination), but negative serology does not absolutely exclude infection with T. pallidum, particularly in an immunocompromised host. Parenteral penicillin remains the treatment of choice for cardiovascular syphilis: the World Health Organization and European and United States guidelines recommend benzathine benzylpenicillin 2.4 × 106 units administered once weekly for 3 weeks by the intramuscular route.