ICD-10 Code A81.1 – Subacute sclerosing panencephalitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A81.1 – Subacute sclerosing panencephalitis
What it is
A81.1 identifies subacute sclerosing panencephalitis, a rare progressive brain disorder linked to persistent measles virus infection. It causes gradual neurological decline over time.
Clinical signs
Clinical features vary; refer to documentation. Typical findings include cognitive decline, behavioral changes, myoclonus, and worsening neurologic function in a patient with a compatible history.
When to use this code
Use A81.1 when the provider documents subacute sclerosing panencephalitis or SSPE. Code it for confirmed diagnosis, suspected diagnosis documented as such, or ongoing management of the condition. If the record only notes encephalopathy or seizure disorder without SSPE, check documentation.
Do not use for
Do not use this code for acute measles, nonspecific viral encephalitis, or other demyelinating disease unless SSPE is specifically documented. Check documentation when the diagnosis is unclear.
Coding tip
Verify that the chart explicitly names SSPE or subacute sclerosing panencephalitis before assigning A81.1.