What is the major complication of untreated syphilis?

Neurosyphilis is the major complication of untreated syphilis because it represents a severe late manifestation of the disease that occurs when the Treponema pallidum bacteria invade the central nervous system. Untreated syphilis can progress through different stages, and if it remains unresolved, it may reach a stage where the bacteria can lead to serious neurological problems.

Neurosyphilis can manifest in various forms, such as asymptomatic neurosyphilis, meningovascular syphilis, and tabes dorsalis, each with distinct clinical presentations. This complication can cause alterations in mental status, seizures, strokes, and other significant neurological deficits.

While the other options involve sexually transmitted infections or conditions that may be associated with the risky behaviors that lead to syphilis, they are not direct complications of untreated syphilis itself. Gonorrhea and herpes simplex virus infection are different sexually transmitted infections, not complications arising from syphilis. HIV transmission is a risk factor in the context of syphilis; however, it does not directly stem from untreated syphilis nor does it reflect a specific complication like neurosyphilis does. Thus, the distinct severe complications that arise from untreated syphilis underscore the importance of