Subacute sclerosing panencephalitis

This code represents a rare, progressive, and fatal neurodegenerative disease that affects the central nervous system, occurring as a late complication of measles virus infection. It is characterized by inflammation and demyelination of the brain, leading to cognitive decline, seizures, and motor dysfunction. The subacute nature indicates a gradual onset and progression of symptoms over months to years.

Assign this code for patients diagnosed with subacute sclerosing panencephalitis, typically identified through a history of measles infection, characteristic neurological symptoms, and supportive laboratory findings such as elevated measles antibody titers in cerebrospinal fluid. Documentation should clearly state the diagnosis of subacute sclerosing panencephalitis.

• Ensure documentation specifies "subacute" to differentiate from other forms of encephalitis.
• Do not confuse with acute post-infectious encephalomyelitis, which has a different etiology and clinical course.
• Code any associated neurological manifestations or complications, such as seizures (G40.-), as secondary diagnoses.