G04.0
Acute disseminated encephalitis and encephalomyelitis (ADEM)
G04.0 is a non-billable ICD-10-CM code header for acute disseminated encephalitis and encephalomyelitis (ADEM). Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are G04.00 Acute disseminated encephalitis and encephalomyelitis, unspecified; G04.01 Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM) and G04.02 Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis. Its coding notes include 3 Excludes1 entries and 15 Excludes2 entries.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (8 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Includes
Further defines or gives examples of the content of the category.
- acute ascending myelitis
- meningoencephalitis
- meningomyelitis