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ICD-10-CM 2027

ICD-10 code for leukoencephalitis

G04.81

Other encephalitis and encephalomyelitis

From the official ICD-10-CM alphabetic index entry “Leukoencephalitis”. Page updated September 29, 2026.

About coding leukoencephalitis

The ICD-10-CM code for leukoencephalitis is G04.81 (Other encephalitis and encephalomyelitis). The official index lists 5 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on G04.81.

Within G04.8, choose G04.81 (Other encephalitis and encephalomyelitis) only when documentation doesn't support a more specific option: acute flaccid myelitis (G04.82) and other myelitis (G04.89).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, relative weight 5.7444), DRG 024 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC, relative weight 3.9708), DRG 097 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with MCC, relative weight 3.8226), DRG 098 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC, relative weight 2.2706), DRG 099 (Non-Bacterial Infection of Nervous System Except Viral Meningitis without CC/MCC, relative weight 1.5256), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506) and 2 more, in MDC 01 (Diseases and Disorders of the Nervous System) and MDC 25 (Human Immunodeficiency Virus Infections), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

More specific leukoencephalitis codes (official index)

  • acute (subacute) hemorrhagic G36.1 — Acute and subacute hemorrhagic leukoencephalitis [Hurst]
  • postimmunization or postvaccinal G04.02 — Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis
  • postinfectious G04.01 — Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)
  • subacute sclerosing A81.1 — Subacute sclerosing panencephalitis
  • van Bogaert's (sclerosing) A81.1 — Subacute sclerosing panencephalitis

Common questions about leukoencephalitis ICD-10 codes

What is the ICD-10 code for leukoencephalitis?

G04.81 — Other encephalitis and encephalomyelitis. More specific codes apply when the documentation supports them: G36.1, G04.02, G04.01, A81.1 and others below.

What is the ICD-10 code for acute hemorrhagic leukoencephalitis?

G36.1 — Acute and subacute hemorrhagic leukoencephalitis [Hurst].

What is the ICD-10 code for postinfectious leukoencephalitis?

G04.01 — Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM).

What is the ICD-10 code for subacute sclerosing leukoencephalitis?

A81.1 — Subacute sclerosing panencephalitis.

What is the ICD-10 code for van bogaert's leukoencephalitis?

A81.1 — Subacute sclerosing panencephalitis.

Is G04.81 billable?

Yes. G04.81 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can G04.81 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict G04.81 as a principal diagnosis.

Is G04.81 a CC or MCC?

G04.81 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.