Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum.

The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, and tertiary). The primary stage classically presents with a single chancre (a firm, painless, non-itchy skin ulceration) but there may be multiple sores. In secondary syphilis a diffuse rash occurs, which frequently involves the palms of the hands and soles of the feet. There may also be sores in the mouth or vagina. In latent syphilis, which can last for years, there are little to no symptoms.

In tertiary syphilis there are gummas (soft non-cancerous growths), neurological, or heart symptoms.

Syphilis has been known as “the great imitator” as it may cause symptoms similar to many other diseases.

The central nervous system (CNS) may be involved at any stage of syphilis infection in about 5% to 10% of untreated patients). CNS involvement in syphilis patients is classified into four syndromes : syphilitic meningitis, meningovascular syphilis, and parenchymatous and gummatous neurosyphilis. Differentiation from a brain mass in HIV-negative patients with syphilis is a challenge to clinicians.

Routine examination of cerebrospinal fluid analysis includes visual observation of color and clarity and tests for glucose, protein, lactate, lactate dehydrogenase, red blood cell count, white blood cell count with differential, syphilis serology (testing for antibodies indicative of syphilis), Gram stain, and bacterial culture.

Neurosyphilis.