G04.02

Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis

Billable FY2026 2025-10-01 → 2026-09-30

Exclusions 18 never code together

G04code

Excludes1

Excludes2

acute transverse myelitis (G37.3)G37.3
alcoholic encephalopathy (G31.2)G31.2
multiple sclerosis (G35-)G35-
myalgic encephalomyelitis (G93.32)G93.32
subacute necrotizing myelitis (G37.4)G37.4
toxic encephalitis (G92.8)G92.8
toxic encephalopathy (G92.8)G92.8

Excludes1

acute necrotizing hemorrhagic encephalopathy (G04.3-)G04.3-
other noninfectious acute disseminated encephalomyelitis (noninfectious ADEM) (G04.81)G04.81

Excludes2

certain conditions originating in the perinatal period (P04-P96)P04-P96
certain infectious and parasitic diseases (A00-B99)A00-B99
complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
neoplasms (C00-D49)C00-D49
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94

Excludes1 — never code together. The excluded condition and this one are mutually exclusive.

Excludes2 — not included here, but the patient may have both. Code both when documented.

Instructional notes 6

Inclusion terms

Use additional code

G04code

Includes

Index entries leading here 8

Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) G04.90
- acute A86
  - disseminated G04.00
    - postimmunization (postvaccination) G04.02
- due to
  - smallpox inoculation G04.02
- following vaccination or other immunization procedure G04.02
- postimmunization G04.02
- postvaccinal G04.02
Encephalomyelitis G04.90
- acute disseminated G04.00
  - postimmunization G04.02
- postvaccinal G04.02
Meningoencephalomyelitis — see also Meningoencephalitis
- acute NEC (viral) A86
  - disseminated G04.00
    - postimmunization or postvaccination G04.02
- postimmunization or postvaccination G04.02
Leukoencephalitis G04.81
- acute (subacute) hemorrhagic G36.1
  - postimmunization or postvaccinal G04.02
Complication (s) (from) (of)
- vaccination T88.1
  - encephalitis or encephalomyelitis G04.02
  - myelitis G04.02
Encephalopathy (acute) G93.40
- in (due to) (with)
  - vaccination G04.02
Leukoencephalopathy G93.49
- postimmunization and postvaccinal G04.02
Myelitis (acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute) G04.91
- postimmunization G04.02
- postvaccinal G04.02

Alongside this code 2 same parent — G04.0

Additional references

AHA Coding Clinic® Licence required

Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.

Maps to no condition category in any loaded model.

Presence is a property of the code. Untick a model to hide it everywhere.

Present FY2024–FY2027.