ICD-10 Code G09 – Sequelae of inflammatory diseases of central nervous system (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G09 – Sequelae of inflammatory diseases of central nervous system
What it is
G09 identifies lasting effects from a prior inflammatory disease of the central nervous system, such as residual neurologic deficits after the acute illness has resolved. Use it to show the condition is a consequence, not an active infection or inflammation.
Clinical signs
Clinical features vary; refer to documentation. Common residual findings may include weakness, sensory changes, speech difficulty, coordination problems, or cognitive impairment linked to a previous CNS inflammatory disorder.
When to use this code
Use G09 when the record states a current neurologic deficit is due to a past inflammatory disease of the brain, spinal cord, or meninges. The acute disease should no longer be the focus of care. If the provider documents only a history without residual effects, this code is not appropriate.
Do not use for
Do not use G09 for active encephalitis, meningitis, myelitis, or other ongoing CNS inflammation. Check documentation if the note describes a nonspecific neurologic disorder without a clear sequela relationship.
Coding tip
Link the residual condition to the prior inflammatory CNS disease in the documentation before assigning G09.