ICD-10 Code G40.509 – Epileptic seizures related to external causes, not intractable, without status epilepticus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.509 – Epileptic seizures related to external causes, not intractable, without status epilepticus
What it is
This code identifies epileptic seizures attributed to an external cause, when the condition is not intractable and there is no status epilepticus. Use it for documented seizure disorders linked to an outside trigger or cause.
Clinical signs
Typical findings include recurrent seizure episodes with features consistent with epilepsy. Clinical features vary; refer to documentation for the external cause, seizure type, and whether the condition is controlled.
When to use this code
Use this code when the record states epileptic seizures are related to an external cause and the provider documents that they are not intractable. It also applies when there is no status epilepticus. Ensure the documentation supports both the seizure diagnosis and the external cause relationship.
Do not use for
Do not use this code if the seizures are intractable or if status epilepticus is documented. Check documentation if the seizure disorder is not clearly linked to an external cause.
Coding tip
Confirm the provider’s wording for external cause, intractability, and status epilepticus before assigning G40.509.