E03.5 ICD-10-CM Code: Myxedema coma

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for E03.5 in the official ICD-10-CM tabular list, quoted as published.

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

Notes without a marker are published on E03.5 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for E03.5

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

Before you code E03.5

1. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with E03.5. 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 E03.5’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.

   ReviewE89.0

Consider E03.5. 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 E03.5(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with E03.5: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareE89.0

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

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 (2)

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.

• Coma, myxedematous
• Myxedema (adult) (idiocy) (infantile) (juvenile), coma

Don’t confuse E03.5 with…

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

The codes most likely to be picked instead of E03.5 — 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.

• E00— 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 iodine-deficiency related hypothyroidism moves the case to E00; the two are not reported together unless documented as unrelated.

  Full comparison: E03.5 vs E00 →

• E02— 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 iodine-deficiency related hypothyroidism moves the case to E02; the two are not reported together unless documented as unrelated.

  Full comparison: E03.5 vs E02 →

• E89.0— 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 postprocedural hypothyroidism moves the case to E89.0; the two are not reported together unless documented as unrelated.

  Full comparison: E03.5 vs E89.0 →

• E03.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Hypothyroidism, unspecified” takes E03.9; specificity in the record moves it back here.

  Full comparison: E03.5 vs E03.9 →

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

• MCC 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 structured relationships — computed from published CMS and AHRQ datasets

Other codes that name E03.5 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 7 Code First instructions across 5 chapters: D63.8 — Anemia in other chronic diseases classified elsewhere (via E03.-), F02 — Dementia in other diseases classified elsewhere (via E03.-), G13.2 — Systemic atrophy primarily affecting the central nervous system in myxedema (via E03.-), G32.8 — Other specified degenerative disorders of nervous system in diseases classified elsewhere (via E03.-), G63 — Polyneuropathy in diseases classified elsewhere (via E03.-), H28 — Cataract in diseases classified elsewhere (via E03.-), M14.8 — Arthropathies in other specified diseases classified elsewhere (via E03.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 1 Code Also instruction: I27.29 — Other secondary pulmonary hypertension (via E03.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: MCC — Major 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 718 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 4 MS-DRGs: DRG 080 (MDC 01), DRG 081 (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):END001 — Thyroid disorders (default); NVS013 — Coma; stupor; and brain damage.

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 CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Coma, Brain Compression/Anoxic Damage) for risk-adjusted payment.

G93.1 — Anoxic brain damage, not elsewhere classified, G93.5 — Compression of brain, G93.6 — Cerebral edema, P91.0 — Neonatal cerebral ischemia, P91.1 — Acquired periventricular cysts of newborn, P91.2 — Neonatal cerebral leukomalacia, P91.3 — Neonatal cerebral irritability, P91.4 — Neonatal cerebral depression, P91.5 — Neonatal coma, P91.60 — Hypoxic ischemic encephalopathy [HIE], unspecified, P91.61 — Mild hypoxic ischemic encephalopathy [HIE], P91.62 — Moderate hypoxic ischemic encephalopathy [HIE], P91.63 — Severe hypoxic ischemic encephalopathy [HIE], P91.811 — Neonatal encephalopathy in diseases classified elsewhere, P91.819 — Neonatal encephalopathy, unspecified, P91.88 — Other specified disturbances of cerebral status of newborn, P91.9 — Disturbance of cerebral status of newborn, unspecified, R40.20 — Unspecified coma, R40.2110 — Coma scale, eyes open, never, unspecified time, R40.2111 — Coma scale, eyes open, never, in the field [EMT or ambulance], +40 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.

Major Head Injury with Loss of Consciousness > 1 Hour, Major Head Injury with Loss of Consciousness < 1 Hour or Unspecified, Chronic Liver Failure/End-Stage Liver Disorders

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Thyroid disorders, Coma; stupor; and brain damage).

E01.0 — Iodine-deficiency related diffuse (endemic) goiter, E01.1 — Iodine-deficiency related multinodular (endemic) goiter, E01.2 — Iodine-deficiency related (endemic) goiter, unspecified, E01.8 — Other iodine-deficiency related thyroid disorders and allied conditions, E02 — Subclinical iodine-deficiency hypothyroidism, E03.0 — Congenital hypothyroidism with diffuse goiter, E03.1 — Congenital hypothyroidism without goiter, E03.2 — Hypothyroidism due to medicaments and other exogenous substances, E03.3 — Postinfectious hypothyroidism, E03.4 — Atrophy of thyroid (acquired), E03.8 — Other specified hypothyroidism, E03.9 — Hypothyroidism, unspecified, E04.0 — Nontoxic diffuse goiter, E04.1 — Nontoxic single thyroid nodule, E04.2 — Nontoxic multinodular goiter, E04.8 — Other specified nontoxic goiter, E04.9 — Nontoxic goiter, unspecified, E05.00 — Thyrotoxicosis with diffuse goiter without thyrotoxic crisis or storm, E05.01 — Thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm, E05.10 — Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm, +68 more

Same Index main term, other category

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

E00.1 — Congenital iodine-deficiency syndrome, myxedematous type (congenital), E05.90 — Thyrotoxicosis, unspecified without thyrotoxic crisis or storm (localized), E05.91 — Thyrotoxicosis, unspecified with thyrotoxic crisis or storm (localized, with storm), E15 — Nondiabetic hypoglycemic coma (hypoglycemic, nondiabetic), L98.5 — Mucinosis of the skin (cutis), P91.5 — Neonatal coma (newborn), R40.20 — Unspecified coma, R40.211 — Coma scale, eyes open, never (with, opening of eyes), R40.212 — Coma scale, eyes open, to pain (with, opening of eyes, score of, 2), R40.213 — Coma scale, eyes open, to sound (with, opening of eyes, score of, 3), R40.214 — Coma scale, eyes open, spontaneous (with, opening of eyes, spontaneous), R40.221 — Coma scale, best verbal response, none (with, verbal response), R40.222 — Coma scale, best verbal response, incomprehensible words (with, verbal response, score of, 2), R40.223 — Coma scale, best verbal response, inappropriate words (with, verbal response, screaming), R40.224 — Coma scale, best verbal response, confused conversation (with, verbal response, score of, 4), R40.225 — Coma scale, best verbal response, oriented (with, verbal response, oriented), R40.231 — Coma scale, best motor response, none (with, motor response), R40.232 — Coma scale, best motor response, extension (with, motor response, extension), R40.233 — Coma scale, best motor response, abnormal flexion (with, motor response, abnormal), R40.234 — Coma scale, best motor response, flexion withdrawal (with, motor response, score of, 4), +5 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Blood Glucose Test, Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of E03.5 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 E03.5 with these 8 related codes in Claim Check

Hierarchy

• E00-E89 — Chapter 4: Endocrine, Nutritional and Metabolic Diseases (E00-E89) (E00-E89)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E00-E07 — Disorders of thyroid gland[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Code First instructions

• D63.8 — Anemia in other chronic diseases classified elsewhere[Code First](via E03.-): “hypothyroidism (E00.0-E03.9)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• F02 — Dementia in other diseases classified elsewhere[Code First](via E03.-): “hypothyroidism, acquired (E00-E03.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• G13.2 — Systemic atrophy primarily affecting the central nervous system in myxedema[Code First](via E03.-): “hypothyroidism (E03.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• G32.8 — Other specified degenerative disorders of nervous system in diseases classified elsewhere[Code First](via E03.-): “cerebral degeneration (due to) hypothyroidism (E00.0-E03.9)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• G63 — Polyneuropathy in diseases classified elsewhere[Code First](via E03.-): “endocrine disease, except diabetes (E00-E07, E15-E16, E20-E34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• H28 — Cataract in diseases classified elsewhere[Code First](via E03.-): “myxedema (E03.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M14.8 — Arthropathies in other specified diseases classified elsewhere[Code First](via E03.-): “hypothyroidism (E00-E03)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code Also instructions

• I27.29 — Other secondary pulmonary hypertension[Code Also](via E03.-): “hypothyroidism (E00-E03)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• END001 — Thyroid disorders[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• NVS013 — Coma; stupor; and brain damage[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 202 — Coma, Brain Compression/Anoxic Damage [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2027
• DRG 080 — NONTRAUMATIC STUPOR AND COMA WITH MCC[MS-DRG]: “NONTRAUMATIC STUPOR AND COMA WITH MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
• DRG 081 — NONTRAUMATIC STUPOR AND COMA WITHOUT MCC[MS-DRG]: “NONTRAUMATIC STUPOR AND COMA WITHOUT MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
• DRG 791 — PREMATURITY WITH MAJOR PROBLEMS[MS-DRG]: “PREMATURITY WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
• DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS[MS-DRG]: “FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027

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

• Coma, myxedematous[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Myxedema (adult) (idiocy) (infantile) (juvenile), coma[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• E03 — Other hypothyroidism[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.0 — Congenital hypothyroidism with diffuse goiter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.1 — Congenital hypothyroidism without goiter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.2 — Hypothyroidism due to medicaments and other exogenous substances[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.3 — Postinfectious hypothyroidism[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.4 — Atrophy of thyroid (acquired)[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.8 — Other specified hypothyroidism[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• E03.9 — Hypothyroidism, unspecified[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 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 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 E03.5 in its code family, with their registry titles.

• E03 — Other hypothyroidism
• E03.0 — Congenital hypothyroidism with diffuse goiter
• E03.1 — Congenital hypothyroidism without goiter
• E03.2 — Hypothyroidism due to medicaments and other exogenous substances
• E03.3 — Postinfectious hypothyroidism
• E03.4 — Atrophy of thyroid (acquired)
• E03.8 — Other specified hypothyroidism
• E03.9 — Hypothyroidism, unspecified

View all codes in the E03 family