ICD-10 Code G40.B – Juvenile myoclonic epilepsy [impulsive petit mal] (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.B – Juvenile myoclonic epilepsy [impulsive petit mal]
What it is
G40.B identifies juvenile myoclonic epilepsy, a seizure disorder that usually begins in adolescence. It is used when the diagnosis specifically documents juvenile myoclonic epilepsy or impulsive petit mal.
Clinical signs
Typical features include brief myoclonic jerks, often soon after waking, and may also include generalized tonic-clonic seizures. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents juvenile myoclonic epilepsy as the confirmed diagnosis. It is appropriate in neurology notes, discharge summaries, and problem lists when the seizure type is identified as JME. If the record only says “seizure disorder,” check documentation for a more specific diagnosis.
Do not use for
Do not use this code for other epilepsy syndromes, isolated febrile seizures, or nonspecific convulsions. If the chart does not clearly identify juvenile myoclonic epilepsy, check documentation.
Coding tip
Assign the code only when the provider names juvenile myoclonic epilepsy; do not infer it from myoclonic jerks alone.