Deciphering the Great Imitator: Syphilis and Neurosyphilis.

Syphilis is an infectious disease caused by . Often known as the "great imitator," it has periods of active disease and periods of latency. Serologic syphilis testing can be divided into treponemal and non-treponemal tests, and multiple tests are required to prove infection. Standardized algorithms exist for syphilis testing and diagnosis. Neurosyphilis, which is often the result of the progression of untreated syphilis, can be life-threatening and requires intravenous antibiotics. Despite the significant challenge of diagnosing and treating neurosyphilis, there are no standardized testing algorithms available. Typically, the cerebral spinal fluid (CSF) venereal disease research laboratory (VDRL) test is considered the gold standard despite low sensitivity. The CSF fluorescent treponemal antibody absorption (FTA-ABS) test is more sensitive despite being less specific and is often the better testing option. This case illustrates a patient with a clinical presentation strongly suggestive of neurosyphilis despite negative initial lab testing and argues for the emergence of a standardized algorithm to guide clinicians.