ICD-10 Code G40.813 – Lennox-Gastaut syndrome, intractable, with status epilepticus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.813 – Lennox-Gastaut syndrome, intractable, with status epilepticus
What it is
This code identifies Lennox-Gastaut syndrome when seizures remain intractable and the patient is in status epilepticus. Use it for a severe epilepsy syndrome with ongoing seizure activity that does not respond well to treatment.
Clinical signs
Clinical features vary; refer to documentation. Commonly documented findings include multiple seizure types, developmental impairment, and persistent or recurrent seizures consistent with status epilepticus.
When to use this code
Use this code when the provider documents Lennox-Gastaut syndrome, intractable, and status epilepticus together. It is appropriate when the record clearly supports both the refractory nature of the epilepsy and the active status epilepticus episode.
If the note only states Lennox-Gastaut syndrome without intractable disease or status epilepticus, choose a more specific or less specific code as documented. Check documentation when seizure activity or control status is unclear.
Do not use for
Do not use this code for Lennox-Gastaut syndrome without intractability or without status epilepticus. Also avoid it when the chart documents a different epilepsy syndrome or generalized seizure disorder.
Coding tip
Confirm that the provider explicitly links Lennox-Gastaut syndrome, intractability, and status epilepticus before assigning G40.813.