ICD-10-CM Tabular Index · Chapter 6 · FY 2027 G40

Epilepsy and recurrent seizures (G40) ICD-10-CM

The G40 code range covers epilepsy and recurrent seizures with 94 ICD-10-CM diagnosis codes. 58 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.

✓ Built from the official CMS FY 2027 datasetEffective Oct 1, 2026 – Sep 30, 2027
94
Diagnosis Codes
58
Billable Codes
G40
Code Range
G40–G47
Parent Section

Type 1 Excludes

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.

Type 2 Excludes

A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

ICD-10-CM

Codes in the G40 Range 94 codes · 58 billable

94 of 94 shown
  • G40 Epilepsy and recurrent seizuresNon-billable
  • G40.0 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onsetNon-billable
  • G40.00 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractableNon-billable
  • G40.001 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable, with status epilepticus
  • G40.009 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable, without status epilepticus
  • G40.01 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractableNon-billable
  • G40.011 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, with status epilepticus
  • G40.019 Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, without status epilepticus
  • G40.1 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizuresNon-billable
  • G40.10 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractableNon-billable
  • G40.101 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, with status epilepticus
  • G40.109 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, without status epilepticus
  • G40.11 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractableNon-billable
  • G40.111 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable, with status epilepticus
  • G40.119 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable, without status epilepticus
  • G40.2 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizuresNon-billable
  • G40.20 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractableNon-billable
  • G40.201 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable, with status epilepticus
  • G40.209 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable, without status epilepticus
  • G40.21 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractableNon-billable
  • G40.211 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable, with status epilepticus
  • G40.219 Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable, without status epilepticus
  • G40.3 Generalized idiopathic epilepsy and epileptic syndromesNon-billable
  • G40.30 Generalized idiopathic epilepsy and epileptic syndromes, not intractableNon-billable
  • G40.301 Generalized idiopathic epilepsy and epileptic syndromes, not intractable, with status epilepticus
  • G40.309 Generalized idiopathic epilepsy and epileptic syndromes, not intractable, without status epilepticus
  • G40.31 Generalized idiopathic epilepsy and epileptic syndromes, intractableNon-billable
  • G40.311 Generalized idiopathic epilepsy and epileptic syndromes, intractable, with status epilepticus
  • G40.319 Generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus
  • G40.4 Other generalized epilepsy and epileptic syndromesNon-billable
  • G40.40 Other generalized epilepsy and epileptic syndromes, not intractableNon-billable
  • G40.401 Other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus
  • G40.409 Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus
  • G40.41 Other generalized epilepsy and epileptic syndromes, intractableNon-billable
  • G40.411 Other generalized epilepsy and epileptic syndromes, intractable, with status epilepticus
  • G40.419 Other generalized epilepsy and epileptic syndromes, intractable, without status epilepticus
  • G40.42 Cyclin-Dependent Kinase-Like 5 Deficiency Disorder
  • G40.5 Epileptic seizures related to external causesNon-billable
  • G40.50 Epileptic seizures related to external causes, not intractableNon-billable
  • G40.501 Epileptic seizures related to external causes, not intractable, with status epilepticus
  • G40.509 Epileptic seizures related to external causes, not intractable, without status epilepticus
  • G40.8 Other epilepsy and recurrent seizuresNon-billable
  • G40.80 Other epilepsyNon-billable
  • G40.801 Other epilepsy, not intractable, with status epilepticus
  • G40.802 Other epilepsy, not intractable, without status epilepticus
  • G40.803 Other epilepsy, intractable, with status epilepticus
  • G40.804 Other epilepsy, intractable, without status epilepticus
  • G40.81 Lennox-Gastaut syndromeNon-billable
  • G40.811 Lennox-Gastaut syndrome, not intractable, with status epilepticus
  • G40.812 Lennox-Gastaut syndrome, not intractable, without status epilepticus
  • G40.813 Lennox-Gastaut syndrome, intractable, with status epilepticus
  • G40.814 Lennox-Gastaut syndrome, intractable, without status epilepticus
  • G40.82 Epileptic spasmsNon-billable
  • G40.821 Epileptic spasms, not intractable, with status epilepticus
  • G40.822 Epileptic spasms, not intractable, without status epilepticus
  • G40.823 Epileptic spasms, intractable, with status epilepticus
  • G40.824 Epileptic spasms, intractable, without status epilepticus
  • G40.83 Dravet syndromeNon-billable
  • G40.833 Dravet syndrome, intractable, with status epilepticus
  • G40.834 Dravet syndrome, intractable, without status epilepticus
  • G40.84 KCNQ2-related epilepsyNon-billable
  • G40.841 KCNQ2-related epilepsy, not intractable, with status epilepticus
  • G40.842 KCNQ2-related epilepsy, not intractable, without status epilepticus
  • G40.843 KCNQ2-related epilepsy, intractable, with status epilepticus
  • G40.844 KCNQ2-related epilepsy, intractable, without status epilepticus
  • G40.89 Other seizures
  • G40.9 Epilepsy, unspecifiedNon-billable
  • G40.90 Epilepsy, unspecified, not intractableNon-billable
  • G40.901 Epilepsy, unspecified, not intractable, with status epilepticus
  • G40.909 Epilepsy, unspecified, not intractable, without status epilepticus
  • G40.91 Epilepsy, unspecified, intractableNon-billable
  • G40.911 Epilepsy, unspecified, intractable, with status epilepticus
  • G40.919 Epilepsy, unspecified, intractable, without status epilepticus
  • G40.A Absence epileptic syndromeNon-billable
  • G40.A0 Absence epileptic syndrome, not intractableNon-billable
  • G40.A01 Absence epileptic syndrome, not intractable, with status epilepticus
  • G40.A09 Absence epileptic syndrome, not intractable, without status epilepticus
  • G40.A1 Absence epileptic syndrome, intractableNon-billable
  • G40.A11 Absence epileptic syndrome, intractable, with status epilepticus
  • G40.A19 Absence epileptic syndrome, intractable, without status epilepticus
  • G40.B Juvenile myoclonic epilepsy [impulsive petit mal]Non-billable
  • G40.B0 Juvenile myoclonic epilepsy, not intractableNon-billable
  • G40.B01 Juvenile myoclonic epilepsy, not intractable, with status epilepticus
  • G40.B09 Juvenile myoclonic epilepsy, not intractable, without status epilepticus
  • G40.B1 Juvenile myoclonic epilepsy, intractableNon-billable
  • G40.B11 Juvenile myoclonic epilepsy, intractable, with status epilepticus
  • G40.B19 Juvenile myoclonic epilepsy, intractable, without status epilepticus
  • G40.C Lafora progressive myoclonus epilepsyNon-billable
  • G40.C0 Lafora progressive myoclonus epilepsy, not intractableNon-billable
  • G40.C01 Lafora progressive myoclonus epilepsy, not intractable, with status epilepticus
  • G40.C09 Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus
  • G40.C1 Lafora progressive myoclonus epilepsy, intractableNon-billable
  • G40.C11 Lafora progressive myoclonus epilepsy, intractable, with status epilepticus
  • G40.C19 Lafora progressive myoclonus epilepsy, intractable, without status epilepticus

Clinical Terms in This Code Range

Definitions from the National Library of Medicine for conditions coded in the G40 range.

Developmental and Epileptic Encephalopathy 2

An X-linked dominant form of early infantile epileptic encephalopathy, caused by mutation(s) in the CDKL5 gene, encoding cyclin-dependent kinase-like 5.

Epilepsia Partialis Continua

A variant of EPILEPSY characterized by continuous focal jerking of a body part over a period of hours, days, or even years without spreading to other body regions. Contractions may be aggravated by movement and are reduced, but not abolished during sleep. ELECTROENCEPHALOGRAPHY demonstrates epileptiform (spike and wave) discharges over the hemisphere opposite to the affected limb in most instances. The repetitive movements may originate from the CEREBRAL CORTEX or from subcortical structures (e.g., BRAIN STEM; BASAL GANGLIA). This condition is associated with Russian Spring and Summer encephalitis (see ENCEPHALITIS, TICK BORNE); Rasmussen syndrome (see ENCEPHALITIS); MULTIPLE SCLEROSIS; DIABETES MELLITUS; BRAIN NEOPLASMS; and CEREBROVASCULAR DISORDERS. (From Brain, 1996 April;119(pt2):393-407; Epilepsia 1993;34;Suppl 1:S29-S36; and Adams et al., Principles of Neurology, 6th ed, p319)

Epilepsy

A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)

Lafora Disease

A form of stimulus sensitive MYOCLONIC EPILEPSY inherited as an autosomal recessive condition. The most common presenting feature is a single seizure in the second decade of life. This is followed by progressive myoclonus, myoclonic seizures, tonic-clonic seizures, focal occipital seizures, intellectual decline, and severe motor and coordination impairments. Most affected individuals do not live past the age of 25 years. Concentric amyloid (Lafora) bodies are found in neurons, liver, skin, bone, and muscle (From Menkes, Textbook of Childhood Neurology, 5th ed, pp111-110).

Lennox Gastaut Syndrome

A childhood-onset epilepsy syndrome.

Myoclonic Epilepsy, Juvenile

A disorder characterized by the onset of myoclonus in adolescence, a marked increase in the incidence of absence seizures (see EPILEPSY, ABSENCE), and generalized major motor seizures (see EPILEPSY, TONIC-CLONIC). The myoclonic episodes tend to occur shortly after awakening. Seizures tend to be aggravated by sleep deprivation and alcohol consumption. Hereditary and sporadic forms have been identified. (From Adams et al., Principles of Neurology, 6th ed, p323)

About the G40 Code Range

Epilepsy and recurring seizures appear here among episodic disorders of the nervous system. The subdivisions distinguish localized-onset seizures, generalized epilepsy, external causes, and named syndromes.

G40.0 describes idiopathic epilepsy with seizures that start in one area. G40.1 and G40.2 separate symptomatic epilepsy with simple versus complex partial seizures. G40.3 and G40.4 distinguish idiopathic from other generalized epilepsy. G40.5 identifies seizures related to external causes.

G40.8 includes other epilepsy, recurrent seizures, and named syndromes. Separate branches identify unspecified epilepsy, absence epileptic syndrome, juvenile myoclonic epilepsy, and Lafora progressive myoclonus epilepsy. Many subdivisions distinguish intractable from not intractable epilepsy.

Questions About This Page

How many billable codes are in the G40 range?

Of the 94 codes in this range, 58 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.

What does the G40 range classify?

The range classifies epilepsy and recurrent seizures. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.

Related References

Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.