G31.8
⚠ Non-billable (Header)Other specified degenerative diseases of nervous system
Diseases of the nervous system (G00-G99)
⚠️ This is a category header code — not billable. Use a more specific child code below.
⚠️ Excludes2
inherited from G31Rules from parent category G31: Other degenerative diseases of nervous system, not elsewhere classified
- • Reye's syndrome (G93.7)
📋 Code Instructions
from G31- • 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-)
Child Codes (9)
G31.80Leukodystrophy, unspecifiedG31.81Alpers diseaseG31.82Leigh's diseaseG31.83Neurocognitive disorder with Lewy bodiesG31.84Mild cognitive impairment of uncertain or unknown etiologyG31.85Corticobasal degenerationG31.86Alexander diseaseG31.87Primary progressive apraxia of speechG31.89Other specified degenerative diseases of nervous system
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CodeG31.8
BillableNo — Header code
ParentG31
CategoryDiseases of the nervous system (G00-G99)
Excludes10 rule(s)
Excludes21 note(s)
Child codes9
Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)