A50.42 Late congenital syphilitic encephalitis

Billable ICD-10-CM code, FY2026. Acts as a Major Complication or Comorbidity (MCC) as a secondary diagnosis.

Applies from A50.4 Late congenital neurosyphilis [juvenile neurosyphilis]

Excludes1 (never code together)

• Hutchinson's triad (A50.53)

Use additional code

• code to identify any associated mental disorder

MS-DRG index

Defines the logic of DRG(s) 097-099 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 090.41 Congenital syphilitic encephalitis (approximate)

Code annotations containing back-references to A50.42

Back-references to A50.4

• Code First: G91.4 Hydrocephalus in diseases classified elsewhere ("congenital syphilis (A50.4-)")

Back-references to A50

• Code First: J99 Respiratory disorders in diseases classified elsewhere ("congenital syphilis (A50.-)")
• Type 2 Excludes: N34 Urethritis and urethral syndrome ("urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)")
• Type 2 Excludes: P37 Other congenital infectious and parasitic diseases ("congenital syphilis (A50.-)")

Diagnosis Index entries for A50.42

• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › in (due to) › syphilis › congenital

Nearby codes

• A50.32 Late congenital syphilitic chorioretinitis
• A50.39 Other late congenital syphilitic oculopathy
• A50.4 Late congenital neurosyphilis [juvenile neurosyphilis]
• A50.40 Late congenital neurosyphilis, unspecified
• A50.41 Late congenital syphilitic meningitis
• A50.42 Late congenital syphilitic encephalitis (this code)
• A50.43 Late congenital syphilitic polyneuropathy
• A50.44 Late congenital syphilitic optic nerve atrophy
• A50.45 Juvenile general paresis
• A50.49 Other late congenital neurosyphilis
• A50.5 Other late congenital syphilis, symptomatic