ICD-10 Code G04.32 – Postimmunization acute necrotizing hemorrhagic encephalopathy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G04.32 – Postimmunization acute necrotizing hemorrhagic encephalopathy
What it is
This code identifies an acute necrotizing hemorrhagic encephalopathy occurring after immunization. It describes severe inflammatory brain injury with bleeding and tissue destruction, documented as vaccine-associated.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include acute altered mental status, seizures, focal neurologic deficits, and encephalopathy with imaging or clinical evidence of hemorrhagic brain involvement.
When to use this code
Use G04.32 when the provider clearly documents postimmunization acute necrotizing hemorrhagic encephalopathy as the diagnosis. You may also use it when the record links the encephalopathic event to a recent immunization and describes the necrotizing hemorrhagic process.
If the chart only says encephalitis, encephalopathy, or a neurologic reaction after vaccination without this specific diagnosis, check documentation before coding. Make sure the clinician’s wording supports the exact condition, not a broader post-vaccine adverse event.
Do not use for
Do not use this code for routine post-vaccination reactions, uncomplicated encephalitis, or nonspecific encephalopathy without hemorrhagic necrotizing features. Check documentation if the record does not clearly connect the condition to immunization.
Coding tip
Code only when the provider explicitly documents this rare diagnosis and the postimmunization relationship is clear.