G32.81 ICD-10-CM Code: Cerebellar ataxia in diseases classified elsewhere

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G32.81 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on G32.81 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for G32.81

MedCoder structured workflow — derived from this code’s own official record

Before you code G32.81

1. G32.81 is a manifestation code (“in diseases classified elsewhere”). Confirm the underlying condition is documented and sequence it first; a manifestation code is not reported as the first-listed or principal diagnosis. The etiology/manifestation convention (Guidelines I.A.13).

   See the official tabular notes · Guide: Manifestation codes and Code First sequencing →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with G32.81. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

Choose the right path

1. Does the documentation support a condition named in G32.81’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

   ReviewG31.2, G13.2

2. Is the underlying (etiologic) condition the Code First note names documented?
   Yes → Sequence the underlying condition first, then G32.81.
   No → A manifestation code needs its underlying condition — query before reporting it.

   ReviewK90.0, M35.9, E85

Consider G32.81. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

The underlying (etiologic) condition

Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

• Excludes1 — check before selecting G32.81(3 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with G32.81: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareG31.2, G13.2

  See the official tabular notes · Guidelines I.A.12.a

• Code First — sequencing check(8 notes)

  Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before G32.81. Do not add an underlying condition the record does not document.

  ReviewK90.0, M35.9, E85

  See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Ataxia, ataxy, ataxic, cerebellar (hereditary), in, specified disease NEC

Don’t confuse G32.81 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G32.81 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• G31.2— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of systemic atrophy primarily affecting the central nervous system in alcoholic cerebellar ataxia moves the case to G31.2; the two are not reported together unless documented as unrelated.

  Full comparison: G32.81 vs G31.2 →

• G13.2— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of systemic atrophy primarily affecting the central nervous system in myxedema moves the case to G13.2; the two are not reported together unless documented as unrelated.

  Full comparison: G32.81 vs G13.2 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• Principal-diagnosis restriction. This is a manifestation code: the Medicare Code Editor requires the underlying condition (etiology) to be sequenced first, with this code reported after it.
• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G32.81 or its code family, from the CMS ICD-10-CM tabular instructional notes and the CMS ICD-10-CM Index to Diseases and Injuries. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Use Additional Code instruction: K90.0 — Celiac disease.

These codes instruct coders to additionally report this code when it applies.

Referenced by 1 Index etiology/manifestation pair: D49.9 — Neoplasm of unspecified behavior of unspecified site.

The ICD-10-CM Index lists these etiology codes with this code in brackets — the manifestation, reported second.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 175 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 058 (MDC 01), DRG 059 (MDC 01), DRG 060 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS006 — Other nervous system disorders (often hereditary or degenerative).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

G25.5 — Other chorea, G25.61 — Drug induced tics, G25.69 — Other tics of organic origin, G25.70 — Drug induced movement disorder, unspecified, G25.71 — Drug induced akathisia, G25.79 — Other drug induced movement disorders, G25.82 — Stiff-man syndrome, G25.83 — Benign shuddering attacks, G25.89 — Other specified extrapyramidal and movement disorders, G25.9 — Extrapyramidal and movement disorder, unspecified, G35.A — Relapsing-remitting multiple sclerosis, G35.B0 — Primary progressive multiple sclerosis, unspecified, G35.B1 — Active primary progressive multiple sclerosis, G35.B2 — Non-active primary progressive multiple sclerosis, G35.C0 — Secondary progressive multiple sclerosis, unspecified, G35.C1 — Active secondary progressive multiple sclerosis, G35.C2 — Non-active secondary progressive multiple sclerosis, G35.D — Multiple sclerosis, unspecified, G36.0 — Neuromyelitis optica [Devic], G36.1 — Acute and subacute hemorrhagic leukoencephalitis [Hurst], +155 more

Principal diagnosis restriction (Medicare Code Editor)

Manifestation code — the underlying condition is sequenced first.

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Spinal Cord Disorders/Injuries) for risk-adjusted payment.

B00.82 — Herpes simplex myelitis, B01.12 — Varicella myelitis, B02.24 — Postherpetic myelitis, G04.1 — Tropical spastic paraplegia, G04.82 — Acute flaccid myelitis, G04.89 — Other myelitis, G04.91 — Myelitis, unspecified, G05.4 — Myelitis in diseases classified elsewhere, G14 — Postpolio syndrome, G32.0 — Subacute combined degeneration of spinal cord in diseases classified elsewhere, G37.3 — Acute transverse myelitis in demyelinating disease of central nervous system, G37.4 — Subacute necrotizing myelitis of central nervous system, G83.4 — Cauda equina syndrome, G90.1 — Familial dysautonomia [Riley-Day], G95.0 — Syringomyelia and syringobulbia, G95.11 — Acute infarction of spinal cord (embolic) (nonembolic), G95.19 — Other vascular myelopathies, G95.20 — Unspecified cord compression, G95.29 — Other cord compression, G95.81 — Conus medullaris syndrome, +230 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Quadriplegia, Paraplegia

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other nervous system disorders (often hereditary or degenerative)).

G31.80 — Leukodystrophy, unspecified, G31.81 — Alpers disease, G31.82 — Leigh's disease, G31.84 — Mild cognitive impairment of uncertain or unknown etiology, G31.85 — Corticobasal degeneration, G31.86 — Alexander disease, G31.87 — Primary progressive apraxia of speech, G31.89 — Other specified degenerative diseases of nervous system, G31.9 — Degenerative disease of nervous system, unspecified, G32.0 — Subacute combined degeneration of spinal cord in diseases classified elsewhere, G32.89 — Other specified degenerative disorders of nervous system in diseases classified elsewhere, G90.01 — Carotid sinus syncope, G90.09 — Other idiopathic peripheral autonomic neuropathy, G90.1 — Familial dysautonomia [Riley-Day], G90.3 — Multi-system degeneration of the autonomic nervous system, G90.4 — Autonomic dysreflexia, G90.B — LMNB1-related autosomal dominant leukodystrophy, G93.42 — Megalencephalic leukoencephalopathy with subcortical cysts, G93.43 — Leukoencephalopathy with calcifications and cysts, G93.44 — Adult-onset leukodystrophy with axonal spheroids, +83 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Ataxia, ataxy, ataxic”; these codes share that main term but sit in a different category of the Tabular List.

G11.0 — Congenital nonprogressive ataxia (congenital nonprogressive), G11.10 — Early-onset cerebellar ataxia, unspecified (cerebellar, early-onset), G11.11 — Friedreich ataxia (Friedreich's), G11.19 — Other early-onset cerebellar ataxia (Hunt's), G11.2 — Late-onset cerebellar ataxia (Marie's), G11.3 — Cerebellar ataxia with defective DNA repair (telangiectasia), G11.4 — Hereditary spastic paraplegia (spastic hereditary), G11.8 — Other hereditary ataxias (hereditary, specified NEC), G11.9 — Hereditary ataxia, unspecified (brain), G31.2 — Degeneration of nervous system due to alcohol (cerebellar, alcoholic), G60.0 — Hereditary motor and sensory neuropathy (Roussy-Lévy), G60.2 — Neuropathy in association with hereditary ataxia (hereditary, with neuropathy), I69.093 — Ataxia following nontraumatic subarachnoid hemorrhage (following, cerebrovascular disease, subarachnoid hemorrhage), I69.193 — Ataxia following nontraumatic intracerebral hemorrhage (following, cerebrovascular disease, intracerebral hemorrhage), I69.293 — Ataxia following other nontraumatic intracranial hemorrhage (following, cerebrovascular disease, nontraumatic intracranial hemorrhage NEC), I69.393 — Ataxia following cerebral infarction (following, cerebrovascular disease, cerebral infarction), I69.893 — Ataxia following other cerebrovascular disease (following, cerebrovascular disease, specified disease NEC), I69.993 — Ataxia following unspecified cerebrovascular disease (following, cerebrovascular disease), K90.0 — Celiac disease (gluten, with celiac disease), M35.9 — Systemic involvement of connective tissue, unspecified (gluten), +7 more

Contextual Map

Every relationship of G32.81 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run G32.81 with these 4 related codes in Claim Check

Hierarchy

• G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Excludes1

• G13.2 — Systemic atrophy primarily affecting the central nervous system in myxedema[Excludes1]: “systemic atrophy primarily affecting the central nervous system in myxedema (G13.2)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• G31.2 — Degeneration of nervous system due to alcohol[Excludes1]: “systemic atrophy primarily affecting the central nervous system in alcoholic cerebellar ataxia (G31.2)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Code First

• K90.0 — Celiac disease[Code First]: “celiac disease (with gluten ataxia) (K90.0)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M35.9 — Systemic involvement of connective tissue, unspecified[Code First]: “non-celiac gluten ataxia (M35.9)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Use Additional Code instructions

• K90.0 — Celiac disease[Use Additional Code]: “gluten ataxia (G32.81)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Index etiology/manifestation pairs

• D49.9 — Neoplasm of unspecified behavior of unspecified site[Index manifestation]: “Ataxia, ataxy, ataxic, cerebellar, in, neoplastic disease”— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Clinical classification (CCSR)

• NVS006 — Other nervous system disorders (often hereditary or degenerative)[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 182 — Spinal Cord Disorders/Injuries [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 058 — MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH MCC[MS-DRG]: “MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 059 — MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH CC[MS-DRG]: “MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH CC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 060 — MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITHOUT CC/MCC[MS-DRG]: “MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITHOUT CC/MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 8,892 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Ataxia, ataxy, ataxic, cerebellar (hereditary), in, specified disease NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• G32 — Other degenerative disorders of nervous system in diseases classified elsewhere[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G32.0 — Subacute combined degeneration of spinal cord in diseases classified elsewhere[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G32.8 — Other specified degenerative disorders of nervous system in diseases classified elsewhere[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G32.89 — Other specified degenerative disorders of nervous system in diseases classified elsewhere[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G32.81 in its code family, with their registry titles.

• G32 — Other degenerative disorders of nervous system in diseases classified elsewhere
• G32.0 — Subacute combined degeneration of spinal cord in diseases classified elsewhere
• G32.8 — Other specified degenerative disorders of nervous system in diseases classified elsewhere
• G32.89 — Other specified degenerative disorders of nervous system in diseases classified elsewhere

View all codes in the G32 family