2024 ICD-10-CM Diagnosis Code B01.1

by

Varicella encephalitis, myelitis and encephalomyelitis

  • B01.1 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2024 edition of ICD-10-CM B01.1 became effective on October 1, 2023.
  • This is the American ICD-10-CM version of B01.1 – other international versions of ICD-10 B01.1 may differ.

Applicable To

  • Postchickenpox encephalitis, myelitis and encephalomyelitis

The following code(s) above B01.1 contain annotation back-references

 that may be applicable to B01.1:

  • A00-B99  Certain infectious and parasitic diseases

Clinical Information

  • Inflammation of brain tissue caused by infection with the varicella-zoster virus (herpesvirus 3, human). This condition is associated with immunocompromised states, including the acquired immunodeficiency syndrome. Pathologically, the virus tends to induce a vasculopathy and infect oligodendrocytes and ependymal cells, leading to cerebral infarction, multifocal regions of demyelination, and periventricular necrosis. Manifestations of varicella encephalitis usually occur 5-7 days after onset of herpes zoster and include headache; vomiting; lethargy; focal neurologic deficits; fever; and coma. (from Joynt, Clinical Neurology, 1996, ch 26, pp29-32; hum pathol 1996 sep;27(9):927-38)

Code History

  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change
  • 2024 (effective 10/1/2023): No change

Code annotations containing back-references to B01.1:

Reimbursement claims with a date