2026 ICD-10-CM Diagnosis Code R56.9Unspecified convulsions

ICD-10-CM Codes›R00–R99›R50-R69›R56

ICD-10-CM R56.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R56.9 is a billable ICD-10-CM diagnosis code for unspecified convulsions. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Epilepsy; convulsions.

Code Identity

ICD-10-CM Code
R56.9
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified convulsions
Short Description
Unspecified convulsions
Same as the full description in the CMS dataset.
Parent Code
R56
Convulsions, not elsewhere classified

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR50-R69General symptoms and signs
CategoryR56Convulsions, not elsewhere classified
This CodeR56.9Unspecified convulsions

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute repetitive seizure
  • Acute seizure due to infection of central nervous system
  • Blood magnesium below reference range
  • Blood magnesium outside reference range
  • Central convulsion
  • Cortical blindness
  • Daily seizures
  • Disorder of beta and omega amino acid metabolism
  • Disorder of gamma aminobutyric acid metabolism
  • Disorder of lysine and hydroxylysine metabolism
  • Early-onset seizures, distal limb anomalies, facial dysmorphism, global developmental delay syndrome
  • EEG abnormality with seizure
  • Emergency epilepsy treatment since last appointment
  • Epilepsy monitoring status
  • Epileptic cry
  • Fall due to seizure
  • Familial psoriasis
  • Folinic acid responsive developmental and epileptic encephalopathy
  • Genetic syndromic childhood obesity
  • Global developmental delay, neuro-ophthalmological abnormalities, seizures, intellectual disability syndrome
  • GNAO1-related developmental delay, seizures, movement disorder spectrum
  • Hereditary cerebellar atrophy
  • Hypoglycemia-induced convulsion
  • Intellectual disability, seizures, abnormal gait, facial dysmorphism syndrome
  • Intellectual disability, seizures, hypotonia, ophthalmologic, skeletal anomalies syndrome
  • Intellectual disability, seizures, macrocephaly, obesity syndrome
  • IRF2BPL-related regressive neurodevelopmental disorder, dystonia, seizures syndrome
  • Left ventricular myocardial noncompaction cardiomyopathy
  • Lethal left ventricular non-compaction, seizures, hypotonia, cataract, developmental delay syndrome
  • Lowered convulsive threshold
  • Many seizures a day
  • Microcephaly, seizure, intellectual disability, heart disease syndrome
  • Neurodevelopmental delay, seizures, ophthalmic anomalies, osteopenia, cerebellar atrophy syndrome
  • Osteogenesis imperfecta, retinopathy, seizures, intellectual disability syndrome
  • Perceptual disturbance due to alcohol withdrawal
  • Perceptual disturbances and seizures co-occurrent and due to alcohol withdrawal
  • Perceptual disturbances and seizures co-occurrent and due to hypnotic withdrawal
  • Perceptual disturbances and seizures co-occurrent and due to psychoactive substance withdrawal
  • Perceptual disturbances and seizures co-occurrent and due to sedative withdrawal
  • Perceptual disturbances co-occurrent and due to hypnotic withdrawal
  • Perceptual disturbances co-occurrent and due to psychoactive substance withdrawal
  • Perceptual disturbances co-occurrent and due to sedative withdrawal
  • Post-ictal state
  • Postseizure headache
  • Posttraumatic seizure
  • Primary hyperaldosteronism, seizures, neurological abnormalities syndrome
  • Primary hypomagnesemia, generalized seizures, intellectual disability, obesity syndrome
  • Progressive microcephaly, seizures, cortical blindness, developmental delay syndrome
  • Progressive microcephaly, seizures, cortical blindness, developmental delay with combined immunodeficiency due to DIAPH1 mutation
  • Pyridoxine-dependent developmental and epileptic encephalopathy
  • Raised convulsive threshold
  • Recurrent seizure
  • Seizure
  • Seizure co-occurrent and due to hypnotic withdrawal
  • Seizure co-occurrent and due to psychoactive substance withdrawal
  • Seizure co-occurrent and due to sedative withdrawal
  • Seizure co-occurrent and due to substance withdrawal
  • Seizure disorder
  • Seizure disorder as sequela of stroke
  • Seizure due to migraine with aura
  • Seizures and intellectual disability due to hydroxylysinuria
  • Seizures complicating infection
  • Situation-related seizures
  • Tetanic convulsion
  • Traumatic injury due to seizure
  • Uremic convulsion
  • Ventricular myocardial noncompaction cardiomyopathy
  • X-linked intellectual disability with seizure and psoriasis syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Convulsion disorder
  • Fit NOS
  • Recurrent convulsions
  • Seizure(s) (convulsive) NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Convulsions(idiopathic)
    • Convulsions(idiopathic)
      • recurrent
    • Disorder(of)
      • paroxysmal, mixed
    • Fit
    • Seizure(s)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS009
Epilepsy; convulsions
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Cortical Blindness

    visual impairment due to visual cortex dysfunction.

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 R56.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
780.39 Convulsions NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R56.9Overview

Is R56.9 (Convulsions, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified convulsions on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R56.9 group to?

When unspecified convulsions 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 R56.9 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the unspecified convulsions is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R56.9?

Under the General Equivalence Mappings, unspecified convulsions converts to ICD-9-CM 780.39 (convulsions NEC). The mapping is approximate, so confirm the match fits the documentation.

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.