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Q07.02 ICD-10-CM Code: Arnold-Chiari syndrome with hydrocephalus

Compare with another code for Q07.02Check this code on a claim

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Official instructions
2 Excludes1 · 3 Excludes2
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 72 · RxHCC V08 category 155

What these terms mean →

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

Excludes1from Q07.0Not reported with this code unless documented as unrelated
  • Arnold-Chiari syndrome, type III (Q01.-)
  • Arnold-Chiari syndrome, type IV (Q04.8)
Excludes2Not included here; may be reported together
  • congenital central alveolar hypoventilation syndrome (G47.35) (from Q07)
  • familial dysautonomia Riley-Day
  • neurofibromatosis (nonmalignant) (Q85.0-) (from Q07)

Where it sits Source: CMS/NCHS

Under:Chapter 17: Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-QA1) (Q00-QA1)Q00-Q07 Congenital malformations of the nervous systemQ07 Other congenital malformations of nervous systemQ07.0 Arnold-Chiari syndrome

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 091 — OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC (MDC 01)
  • MS-DRG 092 — OTHER DISORDERS OF NERVOUS SYSTEM WITH CC (MDC 01)
  • MS-DRG 093 — OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC (MDC 01)
  • MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 182 — Spinal Cord Disorders/Injuries

Other models: CMS-HCC V22 HCC 72 · RxHCC V08 HCC 155

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for Q07.02 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on Q07.02 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from Q07.0

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Coder workflow for Q07.02

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

Before you code Q07.02

  1. Q07.02’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

    Guide: Combination codes →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with Q07.02. 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 Q07.02’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.

    ReviewQ01, Q04.8

Consider Q07.02. 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 associated condition or complication
Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

Official instructions as workflow

  • Excludes1 — check before selecting Q07.02(2 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with Q07.02: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareQ01, Q04.8

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

  • Excludes2 — not part of Q07.02(3 notes)

    Coding workflow: The conditions named in this note are not included in Q07.02. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareG47.35, Q85.0

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

Coding decision scenarios

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

Documentation: Both the condition Q07.02 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewQ01, Q04.8

Documentation: Only one of the components this code’s title joins is documented.

Coding question: Is Q07.02 supported?

Path: Review the code for the documented component on its own.

Reason: A combination code is assigned only when it fully identifies the documented conditions; otherwise the documented component takes its own code (Guidelines I.B.9).

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.

Don’t confuse Q07.02 with…

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

The codes most likely to be picked instead of Q07.02 — 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.

  • Q01— 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 Arnold-Chiari syndrome, type III moves the case to Q01; the two are not reported together unless documented as unrelated.

    Full comparison: Q07.02 vs Q01 →

  • Q04.8— 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 Arnold-Chiari syndrome, type IV moves the case to Q04.8; the two are not reported together unless documented as unrelated.

    Full comparison: Q07.02 vs Q04.8 →

  • G47.35— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of congenital central alveolar hypoventilation syndrome adds G47.35; it is not part of this code and both may be reported when both are documented.

    Full comparison: Q07.02 vs G47.35 →

  • Q85.0— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of neurofibromatosis (nonmalignant) adds Q85.0; it is not part of this code and both may be reported when both are documented.

    Full comparison: Q07.02 vs Q85.0 →

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.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Arnold-Chiari syndrome with hydrocephalus is a billable ICD-10-CM diagnosis code (Q07.02).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

  • CC as a secondary diagnosis (FY2027). 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-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name Q07.02 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Excludes1 notes across 2 chapters: G91 — Hydrocephalus (via Q07.-), Q03 — Congenital hydrocephalus (via Q07.0.-), Q05 — Spina bifida (via Q07.0.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 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 65 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 5 MS-DRGs: DRG 091 (MDC 01), DRG 092 (MDC 01), DRG 093 (MDC 01), DRG 791 (MDC 15), DRG 793 (MDC 15).

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

Clinical classification (AHRQ CCSR):MAL004 — Nervous system congenital anomalies (default).

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.

Q05.7 — Lumbar spina bifida without hydrocephalus, Q05.8 — Sacral spina bifida without hydrocephalus, Q05.9 — Spina bifida, unspecified, Q06.0 — Amyelia, Q06.1 — Hypoplasia and dysplasia of spinal cord, Q06.3 — Other congenital cauda equina malformations, Q06.8 — Other specified congenital malformations of spinal cord, Q06.9 — Congenital malformation of spinal cord, unspecified, Q07.00 — Arnold-Chiari syndrome without spina bifida or hydrocephalus, Q07.01 — Arnold-Chiari syndrome with spina bifida, Q07.03 — Arnold-Chiari syndrome with spina bifida and hydrocephalus, Q07.8 — Other specified congenital malformations of nervous system, Q07.9 — Congenital malformation of nervous system, unspecified, Q87.11 — Prader-Willi syndrome, Q87.19 — Other congenital malformation syndromes predominantly associated with short stature, Q87.2 — Congenital malformation syndromes predominantly involving limbs, Q87.3 — Congenital malformation syndromes involving early overgrowth, Q87.40 — Marfan syndrome, unspecified, Q87.410 — Marfan syndrome with aortic dilation, Q87.418 — Marfan syndrome with other cardiovascular manifestations, +44 more

Same CMS-HCC risk category (V28)

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

Q05.9 — Spina bifida, unspecified, Q06.0 — Amyelia, Q06.1 — Hypoplasia and dysplasia of spinal cord, Q06.2 — Diastematomyelia, Q06.3 — Other congenital cauda equina malformations, Q06.4 — Hydromyelia, Q06.8 — Other specified congenital malformations of spinal cord, Q06.9 — Congenital malformation of spinal cord, unspecified, Q07.00 — Arnold-Chiari syndrome without spina bifida or hydrocephalus, Q07.01 — Arnold-Chiari syndrome with spina bifida, Q07.03 — Arnold-Chiari syndrome with spina bifida and hydrocephalus, Q07.8 — Other specified congenital malformations of nervous system, Q07.9 — Congenital malformation of nervous system, unspecified, S14.0XXA — Concussion and edema of cervical spinal cord, initial encounter, S14.0XXD — Concussion and edema of cervical spinal cord, subsequent encounter, S14.101A — Unspecified injury at C1 level of cervical spinal cord, initial encounter, S14.101D — Unspecified injury at C1 level of cervical spinal cord, subsequent encounter, S14.102A — Unspecified injury at C2 level of cervical spinal cord, initial encounter, S14.102D — Unspecified injury at C2 level of cervical spinal cord, subsequent encounter, S14.103A — Unspecified injury at C3 level of cervical spinal cord, initial encounter, +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 (Nervous system congenital anomalies).

Q05.7 — Lumbar spina bifida without hydrocephalus, Q05.8 — Sacral spina bifida without hydrocephalus, Q05.9 — Spina bifida, unspecified, Q06.0 — Amyelia, Q06.1 — Hypoplasia and dysplasia of spinal cord, Q06.2 — Diastematomyelia, Q06.3 — Other congenital cauda equina malformations, Q06.4 — Hydromyelia, Q06.8 — Other specified congenital malformations of spinal cord, Q06.9 — Congenital malformation of spinal cord, unspecified, Q07.00 — Arnold-Chiari syndrome without spina bifida or hydrocephalus, Q07.01 — Arnold-Chiari syndrome with spina bifida, Q07.03 — Arnold-Chiari syndrome with spina bifida and hydrocephalus, Q07.8 — Other specified congenital malformations of nervous system, Q07.9 — Congenital malformation of nervous system, unspecified, Q85.00 — Neurofibromatosis, unspecified, Q85.01 — Neurofibromatosis, type 1, Q85.02 — Neurofibromatosis, type 2, Q85.03 — Schwannomatosis, Q85.09 — Other neurofibromatosis, +29 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Arnold-Chiari disease, obstruction or syndrome”; these codes share that main term but sit in a different category of the Tabular List.

Q04.8 — Other specified congenital malformations of brain

Contextual Map

Every relationship of Q07.02 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 Q07.02 with these 3 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

  • G91 — Hydrocephalus[Excludes1](via Q07.-): “Arnold-Chiari syndrome with hydrocephalus (Q07.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • Q03 — Congenital hydrocephalus[Excludes1](via Q07.0.-): “Arnold-Chiari syndrome, type II (Q07.0-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • Q05 — Spina bifida[Excludes1](via Q07.0.-): “Arnold-Chiari syndrome, type II (Q07.0-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

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

MS-DRG Grouper

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. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027
  • MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period[MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — 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.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Arnold-Chiari disease, obstruction or syndrome (type II), with, hydrocephalus[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes

Change history

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

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

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.

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 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 — v44 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-derived 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 editorial 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.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "Q07.02 — Arnold-Chiari syndrome with hydrocephalus." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/q07.02-arnold-chiari-syndrome-with-hydrocephalus

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Arnold-Chiari syndrome with hydrocephalus

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to Q07.02 in its code family, with their registry titles.

View all codes in the Q07 family