Coding and coverage · ICD-10-CM
G40.814 Lennox-Gastaut syndrome, intractable, without status epilepticus
Instructional notes
Chapter 6
Excludes2Not included here: the patient may have both; report both when both are present.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
G40
Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
Excludes2Not included here: the patient may have both; report both when both are present.
Notes
- the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled
G40.8
Inclusion terms
- Epilepsies and epileptic syndromes undetermined as to whether they are focal or generalized
- Landau-Kleffner syndrome
Chapter 6: Diseases of the nervous system · G40-G47 Episodic and paroxysmal disorders (G40-G47)
Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.
Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.