R56.1 ICD-10-CM Code: Post traumatic seizures

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for R56.1 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 R56.1 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for R56.1

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

Before you code R56.1

1. Check whether an established diagnosis that explains this sign or symptom is documented. If one is, review whether the documented diagnosis changes the coding pathway: a symptom that is integral to a confirmed diagnosis is not reported separately, while one not routinely associated with it may be. Signs and symptoms are reported when no definitive diagnosis is established (Guidelines I.B.4, I.B.5, I.B.6, I.C.18.b).

   Guide: Symptom code vs confirmed diagnosis →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with R56.1. 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. Is an established diagnosis that explains this sign or symptom documented?
   Yes → Review whether the documented diagnosis changes the coding pathway: a symptom integral to it is not reported separately.
   No → Continue — the sign or symptom code stands when no definitive diagnosis is established.
2. Does the documentation support a condition named in R56.1’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.

   ReviewG40, F44.5, P90

Consider R56.1. 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).

Official instructions as workflow

• Excludes1 — check before selecting R56.1(4 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with R56.1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareG40, F44.5, P90

  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.

• Convulsions (idiopathic), post traumatic
• Seizure (s), post traumatic

Don’t confuse R56.1 with…

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

The codes most likely to be picked instead of R56.1 — 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.

• G40— 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 post traumatic epilepsy moves the case to G40; the two are not reported together unless documented as unrelated.

  Full comparison: R56.1 vs G40 →

• F44.5— 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 dissociative convulsions and seizures moves the case to F44.5; the two are not reported together unless documented as unrelated.

  Full comparison: R56.1 vs F44.5 →

• P90— 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 newborn convulsions and seizures moves the case to P90; the two are not reported together unless documented as unrelated.

  Full comparison: R56.1 vs P90 →

• R56.9— 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 “Unspecified convulsions” takes R56.9; specificity in the record moves it back here.

  Full comparison: R56.1 vs R56.9 →

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

• 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 R56.1 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 1 Excludes1 note: G40 — Epilepsy and recurrent seizures.

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

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 89 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 100 (MDC 01), DRG 101 (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):NVS009 — Epilepsy; convulsions (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.

G40.911 — Epilepsy, unspecified, intractable, with status epilepticus, G40.919 — Epilepsy, unspecified, intractable, without status epilepticus, G40.A01 — Absence epileptic syndrome, not intractable, with status epilepticus, G40.A09 — Absence epileptic syndrome, not intractable, without status epilepticus, G40.A11 — Absence epileptic syndrome, intractable, with status epilepticus, G40.A19 — Absence epileptic syndrome, intractable, without status epilepticus, G40.B01 — Juvenile myoclonic epilepsy, not intractable, with status epilepticus, G40.B09 — Juvenile myoclonic epilepsy, not intractable, without status epilepticus, G40.B11 — Juvenile myoclonic epilepsy, intractable, with status epilepticus, G40.B19 — Juvenile myoclonic epilepsy, intractable, without status epilepticus, G40.C01 — Lafora progressive myoclonus epilepsy, not intractable, with status epilepticus, G40.C09 — Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus, G40.C11 — Lafora progressive myoclonus epilepsy, intractable, with status epilepticus, G40.C19 — Lafora progressive myoclonus epilepsy, intractable, without status epilepticus, G93.81 — Temporal sclerosis, G93.89 — Other specified disorders of brain, G93.9 — Disorder of brain, unspecified, G96.9 — Disorder of central nervous system, unspecified, G98.0 — Neurogenic arthritis, not elsewhere classified, G98.8 — Other disorders of nervous system, +68 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Seizure Disorders and Convulsions) for risk-adjusted payment.

G40.909 — Epilepsy, unspecified, not intractable, without status epilepticus, G40.911 — Epilepsy, unspecified, intractable, with status epilepticus, G40.919 — Epilepsy, unspecified, intractable, without status epilepticus, G40.A01 — Absence epileptic syndrome, not intractable, with status epilepticus, G40.A09 — Absence epileptic syndrome, not intractable, without status epilepticus, G40.A11 — Absence epileptic syndrome, intractable, with status epilepticus, G40.A19 — Absence epileptic syndrome, intractable, without status epilepticus, G40.B01 — Juvenile myoclonic epilepsy, not intractable, with status epilepticus, G40.B09 — Juvenile myoclonic epilepsy, not intractable, without status epilepticus, G40.B11 — Juvenile myoclonic epilepsy, intractable, with status epilepticus, G40.B19 — Juvenile myoclonic epilepsy, intractable, without status epilepticus, G40.C01 — Lafora progressive myoclonus epilepsy, not intractable, with status epilepticus, G40.C09 — Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus, G40.C11 — Lafora progressive myoclonus epilepsy, intractable, with status epilepticus, G40.C19 — Lafora progressive myoclonus epilepsy, intractable, without status epilepticus, G93.45 — Developmental and epileptic encephalopathy, P90 — Convulsions of newborn, R56.00 — Simple febrile convulsions, R56.01 — Complex febrile convulsions, R56.9 — Unspecified convulsions, +43 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Epilepsy; convulsions).

G40.901 — Epilepsy, unspecified, not intractable, with status epilepticus, G40.909 — Epilepsy, unspecified, not intractable, without status epilepticus, G40.911 — Epilepsy, unspecified, intractable, with status epilepticus, G40.919 — Epilepsy, unspecified, intractable, without status epilepticus, G40.A01 — Absence epileptic syndrome, not intractable, with status epilepticus, G40.A09 — Absence epileptic syndrome, not intractable, without status epilepticus, G40.A11 — Absence epileptic syndrome, intractable, with status epilepticus, G40.A19 — Absence epileptic syndrome, intractable, without status epilepticus, G40.B01 — Juvenile myoclonic epilepsy, not intractable, with status epilepticus, G40.B09 — Juvenile myoclonic epilepsy, not intractable, without status epilepticus, G40.B11 — Juvenile myoclonic epilepsy, intractable, with status epilepticus, G40.B19 — Juvenile myoclonic epilepsy, intractable, without status epilepticus, G40.C01 — Lafora progressive myoclonus epilepsy, not intractable, with status epilepticus, G40.C09 — Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus, G40.C11 — Lafora progressive myoclonus epilepsy, intractable, with status epilepticus, G40.C19 — Lafora progressive myoclonus epilepsy, intractable, without status epilepticus, G93.45 — Developmental and epileptic encephalopathy, R56.00 — Simple febrile convulsions, R56.01 — Complex febrile convulsions, R56.9 — Unspecified convulsions, +42 more

Same Index main term, other category

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

G25.3 — Myoclonus (myoclonic), G40.401 — Other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus (grand mal, not intractable, with status epilepticus), G40.409 — Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus (grand mal), G40.411 — Other generalized epilepsy and epileptic syndromes, intractable, with status epilepticus (grand mal, intractable, with status epilepticus), G40.419 — Other generalized epilepsy and epileptic syndromes, intractable, without status epilepticus (grand mal, intractable), G40.89 — Other seizures (specified NEC), G40.901 — Epilepsy, unspecified, not intractable, with status epilepticus (febrile, with status epilepticus), G40.909 — Epilepsy, unspecified, not intractable, without status epilepticus (disorder), G40.911 — Epilepsy, unspecified, intractable, with status epilepticus (intractable, with status epilepticus), G40.919 — Epilepsy, unspecified, intractable, without status epilepticus (intractable), G40.A — Absence epileptic syndrome (absence), G40.A0 — Absence epileptic syndrome, not intractable (petit mal, not intractable), G40.A01 — Absence epileptic syndrome, not intractable, with status epilepticus (petit mal, not intractable, with status epilepticus), G40.A09 — Absence epileptic syndrome, not intractable, without status epilepticus (petit mal, not intractable, without status epilepticus), G40.A1 — Absence epileptic syndrome, intractable (petit mal, intractable), G40.A11 — Absence epileptic syndrome, intractable, with status epilepticus (petit mal, intractable, with status epilepticus), G40.A19 — Absence epileptic syndrome, intractable, without status epilepticus (petit mal, intractable, without status epilepticus), I67.82 — Cerebral ischemia (apoplectiform), P90 — Convulsions of newborn (newborn), R25.8 — Other abnormal involuntary movements (reflex), +4 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, Hepatitis Testing

Contextual Map

Every relationship of R56.1 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 R56.1 with this related code in Claim Check

Hierarchy

• R00-R99 — Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99) (R00-R99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R50-R69 — General symptoms and signs[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Excludes1

• G40 — Epilepsy and recurrent seizures[Excludes1]: “post traumatic epilepsy (G40.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes1 notes

• G40 — Epilepsy and recurrent seizures[Excludes1]: “post traumatic seizures (R56.1)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• NVS009 — Epilepsy; convulsions[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 201 — Seizure Disorders and Convulsions [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 100 — SEIZURES WITH MCC[MS-DRG]: “SEIZURES WITH MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 101 — SEIZURES WITHOUT MCC[MS-DRG]: “SEIZURES WITHOUT 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

• Convulsions (idiopathic), post traumatic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Seizure (s), post traumatic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• R56 — Convulsions, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R56.0 — Febrile convulsions[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R56.00 — Simple febrile convulsions[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R56.01 — Complex febrile convulsions[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R56.9 — Unspecified convulsions[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 R56.1 in its code family, with their registry titles.

• R56 — Convulsions, not elsewhere classified
• R56.0 — Febrile convulsions
• R56.00 — Simple febrile convulsions
• R56.01 — Complex febrile convulsions
• R56.9 — Unspecified convulsions

View all codes in the R56 family