G31.8
Other specified degenerative diseases of nervous system
Non-billable headerNot valid on its own. Use one of the more specific codes under it.
G31.8 is a non-billable ICD-10-CM code header for other specified degenerative diseases of nervous system. 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 G31.80 Leukodystrophy, unspecified; G31.81 Alpers disease; G31.82 Leigh's disease; G31.83 Neurocognitive disorder with Lewy bodies and 5 more. Its coding notes include a Use additional code instruction and 9 Excludes2 entries.
Use additional code
Add the listed code as a secondary code, if known.
Inherited from G31 Other degenerative diseases of nervous system, not elsewhere classified
- code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify:
- dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
- dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
- dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
- dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
- dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
- mild neurocognitive disorder due to known physiological condition (F06.7-)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Inherited from G31 Other degenerative diseases of nervous system, not elsewhere classified
- Reye's syndrome (G93.7)
Also from chapter/block level (8 notes)
Inherited from Chapter 6 Diseases of the nervous system
- 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)
More specific codes under G31.8 9
- G31.80Leukodystrophy, unspecifiedBillable
- G31.81Alpers diseaseBillable
- G31.82Leigh's diseaseBillable
- G31.83Neurocognitive disorder with Lewy bodiesBillable
- G31.84Mild cognitive impairment of uncertain or unknown etiologyBillable
- G31.85Corticobasal degenerationBillable
- G31.86Alexander diseaseBillable
- G31.87Primary progressive apraxia of speechBillable
- G31.89Other specified degenerative diseases of nervous systemBillable