Late syphilitic encephalitis

This code represents a chronic inflammatory condition of the brain and meninges caused by Treponema pallidum infection, occurring in the late stage of syphilis. It is characterized by progressive neurological deterioration, including cognitive impairment, psychiatric symptoms, and motor deficits, often years after the initial infection.

Use this code when documentation clearly indicates a diagnosis of late-stage syphilis affecting the brain, specifically manifesting as encephalitis. This diagnosis is typically supported by a history of syphilis, positive serological tests (e.g., VDRL, RPR, FTA-ABS), and neurological findings consistent with syphilitic involvement of the central nervous system.

• Ensure documentation specifies "late" or "tertiary" syphilis affecting the brain, as early neurosyphilis has different codes.
• Do not confuse with other forms of neurosyphilis, such as syphilitic meningitis or meningovascular syphilis, which have distinct codes.
• Always sequence this code as the primary diagnosis if it is the reason for the encounter, or as a secondary diagnosis if it is a co-morbidity impacting care.