ICD-10 Code G04.31 – Postinfectious acute necrotizing hemorrhagic encephalopathy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G04.31 – Postinfectious acute necrotizing hemorrhagic encephalopathy
What it is
This code identifies a rare inflammatory brain disorder that occurs after an infection and causes rapid tissue damage with bleeding. Use it for documented postinfectious acute necrotizing hemorrhagic encephalopathy only.
Clinical signs
Typical findings include acute encephalopathy, altered mental status, and neurologic decline after a recent infection. Imaging or specialist documentation may show necrosis and hemorrhagic involvement; clinical features vary, refer to documentation.
When to use this code
Use G04.31 when the provider documents postinfectious acute necrotizing hemorrhagic encephalopathy as the confirmed diagnosis. It is appropriate for inpatient, emergency, or neurology records describing a postinfectious encephalopathic process with necrosis and hemorrhage. Check documentation if the term is abbreviated or uncertain.
Do not use for
Do not use this code for uncomplicated encephalitis, nonspecific encephalopathy, or hemorrhage without the postinfectious necrotizing diagnosis. If documentation does not clearly support this exact condition, check documentation.
Coding tip
Code the condition only when the provider links the encephalopathy to a postinfectious necrotizing hemorrhagic process.