G31.8 ICD-10-CA code: Other specified degenerative diseases of nervous system
G31.8 is the ICD-10-CA code for “Other specified degenerative diseases of nervous system” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.
Official description
G31.8Other specified degenerative diseases of nervous system
Short description: Oth spec degenerative dis nervous system
ICD-10-CA · Canada · Also written G318
Index terms
Entries in CIHI’s alphabetical index that lead to G31.8. Searching the index by the condition the note names is how coders reach this code.
- Alpers' disease
- Leigh's disease
- Degeneration, degenerative, spinal (cord)
- Degeneration, degenerative, spinal (cord), fatty
- Degeneration, degenerative, nervous system, fatty
- Myoencephalopathy, mitochondrial encephalomyopathy
- Encephalomyopathy, mitochondrial (myoencephalopathy)
- Encephalopathy (acute), necrotizing, subacute (Leigh)
- Degeneration, degenerative, spinal (cord), familial NEC
- Degeneration, degenerative, grey matter (brain) (Alpers')
- Degeneration, degenerative, nervous system, specified NEC
- Atrophy, atrophic, brain (cortex) (progressive), presenile NEC
- Degeneration, degenerative, brain (cortical) (progressive), cystic
- Degeneration, degenerative, cortical (cerebellar) (parenchymatous)
- Degeneration, degenerative, brain (cortical) (progressive), childhood, specified NEC
Notes for G31.8
As CIHI prints them, with any note G31.8 takes from the headings above it.
Includes
- Grey-matter degeneration [Alpers]Lewy body(ies) (dementia) (disease) (F02.8*)Mitochondrial encephalomyopathy (myoencephalopathy)Subacute necrotizing encephalopathy [Leigh]
Excludes
Conditions classified elsewhere.
- Reye's syndrome (G93.7)From G31 Other degenerative diseases of nervous system, not elsewhere classified
- Certain:• conditions originating in the perinatal period (P00-P96)• infectious and parasitic diseases (A00-B99)complications of pregnancy, childbirth and the puerperium (O00-O99)congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)endocrine, nutritional and metabolic diseases (E00-E90)injury, poisoning and certain other consequences of external causes (S00-T98)neoplasms (C00-D48)symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)From Chapter 6: Diseases of the nervous system (G00-G99)
Where G31.8 sits
- 1ChapterChapter 6: Diseases of the nervous system (G00-G99)
- 2Block G30-G32Other degenerative diseases of the nervous system
- 3Category G31Other degenerative diseases of nervous system, not elsewhere classified
- 4Valid code G31.8Other specified degenerative diseases of nervous system
Source and release
- Data release
- ICD-10-CA · FY 2026–2027
- Effective date
- Apr 1, 2026
- Publisher
- CIHI
This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.
Frequently asked questions
What does ICD-10-CA code G31.8 mean?
G31.8 is the ICD-10-CA code for “Other specified degenerative diseases of nervous system” in CIHI’s ICD-10-CA FY 2026–2027 release.
Where is G31.8 in ICD-10-CA?
G31.8 sits under G31 Other degenerative diseases of nervous system, not elsewhere classified, within G30-G32 Other degenerative diseases of the nervous system, within Chapter 6: Diseases of the nervous system (G00-G99).
What coding notes apply to G31.8?
ICD-10-CA lists Includes, Excludes notes for G31.8, including those from the headings it sits under. They are listed on this page with where each one comes from.
Which ICD-10-CA release does this page use?
It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.