2026 ICD-10-CM Diagnosis Code R56.1Post traumatic seizures
ICD-10-CM Codes›R00–R99›R50-R69›R56
- Billable — Valid for Submission
- Not Chronic
R56.1 is a billable ICD-10-CM diagnosis code for post traumatic seizures. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 100 through 101. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. Coders also document this condition as posttraumatic seizure. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Epilepsy; convulsions.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Posttraumatic seizure
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
- post traumatic epilepsy G40
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Convulsions (idiopathic) - See Also: Seizure(s); - R56.9
- post traumatic - R56.1
- Seizure (s) - See Also: Convulsions; - R56.9
- post traumatic - R56.1
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Convulsions(idiopathic)
- post traumatic
- Seizure(s)
- post traumatic
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Seizures
Seizures are symptoms of a brain problem. They happen because of sudden, abnormal electrical activity in the brain. When people think of seizures, they often think of convulsions in which a person's body shakes rapidly and uncontrollably. Not all seizures cause convulsions. There are many types of seizures and some have mild symptoms.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert R56.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About R56.1Overview
Is R56.1 (Convulsions, not elsewhere classified) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report post traumatic seizures on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does R56.1 group to?
When post traumatic seizures is the principal diagnosis on an inpatient stay, it groups to MS-DRG 100, 101, with relative weights from 0.9026 to 1.9368 depending on complications. Higher weights mean higher Medicare reimbursement.
Can R56.1 be a principal diagnosis?
Use it with care. This is a symptom code, so once a definitive diagnosis explaining the post traumatic seizures is established, that condition takes the principal position instead.
What is the ICD-9 equivalent of R56.1?
Under the General Equivalence Mappings, post traumatic seizures converts to ICD-9-CM 780.33 (post traumatic seizures). The mapping is a direct match.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
