2026 ICD-10-CM Diagnosis Code G40.409Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus

ICD-10-CM Codes›G00–G99›G40-G47›G40

ICD-10-CM G40.409
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G40.409 is a billable ICD-10-CM diagnosis code for other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Epilepsy; convulsions.

Code Identity

ICD-10-CM Code
G40.409
Billable Status
Yes — Valid for Submission
Code Describes
Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus
Short Description
Oth generalized epilepsy, not intractable, w/o stat epi
Parent Code
G40.40
Other generalized epilepsy and epileptic syndromes, not intractable

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG40Epilepsy and recurrent seizures
This CodeG40.409Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Absence seizure
  • Absence seizure with eyelid myoclonia
  • Atonic epileptic seizure
  • Benign adult familial myoclonic epilepsy
  • Clonic epileptic seizure
  • Combined focal and generalized epilepsy
  • Early infantile epileptic encephalopathy with suppression bursts
  • Epilepsy with myoclonic-atonic seizures
  • Epileptic spasms
  • Familial infantile myoclonic epilepsy
  • Generalized onset atonic epileptic seizure
  • Generalized onset clonic epileptic seizure
  • Generalized onset epileptic seizure
  • Generalized onset epileptic spasms
  • Generalized onset motor epileptic seizure
  • Generalized onset myoclonic epileptic seizure
  • Generalized onset myoclonic-atonic epileptic seizure
  • Generalized onset myoclonic-tonic-clonic epileptic seizure
  • Generalized onset tonic epileptic seizure
  • Generalized onset tonic-clonic epileptic seizure
  • Genetic epilepsy with febrile seizures plus
  • Genetic generalized epilepsy
  • Myoclonic epilepsy in non-progressive encephalopathy
  • Myoclonic epilepsy myopathy sensory ataxia
  • Myoclonic epileptic seizure
  • Perioral myoclonia with absences
  • Pitt-Hopkins syndrome
  • Post infectious grand mal epilepsy
  • Progressive myoclonus epilepsy with ataxia
  • Spinal muscular atrophy with progressive myoclonic epilepsy
  • Tonic epileptic seizure
  • Tonic-clonic epileptic seizure

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.

    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • generalized
        • specified NEC
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • generalized
        • specified NEC
          • not intractable
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • generalized
        • specified NEC
          • not intractable
            • without status epilepticus
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • syndromes
        • generalized
          • specified NEC
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • syndromes
        • generalized
          • specified NEC
            • not intractable
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • syndromes
        • generalized
          • specified NEC
            • not intractable
              • without status epilepticus
    • Myoclonus, myoclonic, myoclonia(familial) (essential) (multifocal) (simplex)
      • epileptica
    • Seizure(s)
      • grand mal
    • Seizure(s)
      • grand mal
        • not intractable
    • Seizure(s)
      • grand mal
        • not intractable
          • without status epilepticus

Clinical ClassificationClinical

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

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

Patient EducationClinical

Epilepsy

Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G40.409 to ICD-9-CMHistory

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

ICD-9-CM
345.10 Gen cnv epil w/o intr ep
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 G40.409Overview

Is G40.409 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does G40.409 group to?

When other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus 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.

What is the ICD-9 equivalent of G40.409?

Under the General Equivalence Mappings, other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus converts to ICD-9-CM 345.10 (gen cnv epil w/o intr ep). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.