G04.31 is a billable ICD-10 code used to specify a medical diagnosis of postinfectious acute necrotizing hemorrhagic encephalopathy. The code is valid during the fiscal year 2023 from October 01, 2022 through September 30, 2023 for the submission of HIPAA-covered transactions.
The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:
- Acute necrotizing encephalopathy of childhood
- Post-infectious encephalitis
Index to Diseases and Injuries References
The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for this diagnosis code are found in the injuries and diseases index:
- - Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) - G04.90
- - Encephalomyelitis - See Also: Encephalitis; - G04.90
Convert to ICD-9 Code
|Source ICD-10 Code||Target ICD-9 Code|
|G04.31||323.62 - Postinf encephalitis NEC|
|Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.|
Encephalitis is an inflammation of the brain. Usually the cause is a viral infection, but bacteria can also cause it. It can be mild or severe. Most cases are mild. You may have flu-like symptoms. With a mild case, you may just need rest, plenty of fluids, and a pain reliever.
Severe cases need immediate treatment. Symptoms of severe cases include:
- Severe headache
- Sudden fever
In babies, additional symptoms may include constant crying, poor feeding, body stiffness, and bulging in the soft spots of the skull.
Severe cases may require a stay in the hospital. Treatments include oral and intravenous (IV) medicines to reduce inflammation and treat infection. Patients with breathing difficulties may need artificial respiration. Some people may need physical, speech, and occupational therapy once the illness is under control.
NIH: National Institute of Neurological Disorders and Stroke
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Acute necrotizing encephalopathy type 1
Acute necrotizing encephalopathy type 1, also known as susceptibility to infection-induced acute encephalopathy 3 or IIAE3, is a rare type of brain disease (encephalopathy) that occurs following a viral infection such as the flu.
Acute necrotizing encephalopathy type 1 typically appears in infancy or early childhood, although some people do not develop the condition until adolescence or adulthood. People with this condition usually show typical symptoms of an infection, such as fever, cough, congestion, vomiting, and diarrhea, for a few days. Following these flu-like symptoms, affected individuals develop neurological problems, such as seizures, hallucinations, difficulty coordinating movements (ataxia), or abnormal muscle tone. Eventually, most affected individuals go into a coma, which usually lasts for a number of weeks. The condition is described as "acute" because the episodes of illness are time-limited.
People with acute necrotizing encephalopathy type 1 develop areas of damage (lesions) in certain regions of the brain. As the condition progresses, these brain regions develop swelling (edema), bleeding (hemorrhage), and then tissue death (necrosis). The progressive brain damage and tissue loss results in encephalopathy.
Approximately one-third of individuals with acute necrotizing encephalopathy type 1 do not survive their illness and subsequent neurological decline. Of those who do survive, about half have permanent brain damage due to tissue necrosis, resulting in impairments in walking, speech, and other basic functions. Over time, many of these skills may be regained, but the loss of brain tissue is permanent. Other individuals who survive their illness appear to recover completely.
It is estimated that half of individuals with acute necrotizing encephalopathy type 1 are susceptible to recurrent episodes and will have another infection that results in neurological decline; some people may have numerous episodes throughout their lives. Neurological function worsens following each episode as more brain tissue is damaged.
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- FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
- FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
- FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
- FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
- FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
- FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
- FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
- FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)