G04.0

Acute disseminated encephalitis and encephalomyelitis (ADEM)

Not billable — category only 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-G04.3-
other noninfectious acute disseminated encephalomyelitis (noninfectious ADEM) (G04.81)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 3

G04code

Includes

Index entries leading here filed at null

No alphabetic index entry points at this code.

Alongside this code 5 same parent — G04

Subordinate codes 3

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.