ICD-10 Code G40.91 – Epilepsy, unspecified, intractable (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.91 – Epilepsy, unspecified, intractable
What it is
G40.91 identifies epilepsy that is not further specified and remains difficult to control with treatment. Use it when the record documents epilepsy but does not identify a particular seizure type or syndrome.
Clinical signs
Clinical features vary; refer to documentation. Typical records describe recurrent unprovoked seizures, and “intractable” means the condition persists despite appropriate therapy or remains poorly controlled.
When to use this code
Use this code when the clinician documents epilepsy as unspecified and also states it is intractable, refractory, or poorly controlled. It is appropriate when the seizure disorder is confirmed but the type, syndrome, or localization is not documented. Check the note for any more specific epilepsy code before assigning G40.91.
Do not use for
Do not use this code if the record identifies a more specific epilepsy category, such as focal, generalized, or absence epilepsy. Do not use it for a single seizure, seizure-like episodes, or epilepsy described as controlled.
Coding tip
Always code the most specific epilepsy description available, and verify that “intractable” is explicitly documented before using G40.91.