ICD-10 Code G40.5 – Epileptic seizures related to external causes (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.5 – Epileptic seizures related to external causes
What it is
G40.5 identifies epileptic seizures linked to an external cause rather than idiopathic epilepsy alone. Use it when the record shows seizures occurring in relation to an outside trigger or injury-related factor.
Clinical signs
Clinical features vary; refer to documentation. Records may describe recurrent seizure activity, altered awareness, convulsions, or events tied to a known external precipitant.
When to use this code
Use this code when the provider documents epileptic seizures related to an external cause and the diagnosis is confirmed in the chart. It may apply when the seizure disorder is specifically attributed to an outside factor, not just a general seizure history. Check documentation for the exact cause and any additional codes needed.
Do not use for
Do not use this code for unspecified seizures, syncope, or seizure-like episodes without a documented epileptic diagnosis. Avoid it when the record does not connect the seizures to an external cause.
Coding tip
Code the external cause and any associated injury or condition separately when documentation supports them.