G40.509 – Epileptic seizures related to external causes, not intractable, without status epilepticus

ICD-10-CM 2027 diagnosis code · Episodic and paroxysmal disorders

Billable code

ICD-10-CM code G40.509
Code
G40.509 (claims format: G40509)
Description
Epileptic seizures related to external causes, not intractable, without status epilepticus
Short description
Epileptic seiz rel to extrn causes, not ntrct, w/o stat epi
Billable
Yes – valid for HIPAA-covered transactions
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
6. Diseases of the nervous system (G00-G99)
Block
G40-G47 Episodic and paroxysmal disorders
Parent codes
G40 › G40.5 › G40.50

Notes for G40.509

Applicable to:
  • Epileptic seizures related to external causes, NOS

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

G40 – Epilepsy and recurrent seizures

Excludes1 (not coded here):
  • conversion disorder with seizures (F44.5)
  • convulsions NOS (R56.9)
  • post traumatic seizures (R56.1)
  • seizure (convulsive) NOS (R56.9)
  • seizure of newborn (P90)
Excludes2 (not included here):
Notes:
  • the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled

G40.5 – Epileptic seizures related to external causes

Applicable to:
  • Epileptic seizures related to alcohol
  • Epileptic seizures related to drugs
  • Epileptic seizures related to hormonal changes
  • Epileptic seizures related to sleep deprivation
  • Epileptic seizures related to stress
Use additional code:
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
Code also:
  • , if applicable, associated epilepsy and recurrent seizures (G40.-)

Index terms for G40.509

Entries in the ICD-10-CM alphabetic index that lead to this code:

Related codes in G40.50

Frequently asked questions

What is ICD-10 code G40.509?

G40.509 is the ICD-10-CM code for epileptic seizures related to external causes, not intractable, without status epilepticus, in the block G40-G47 (Episodic and paroxysmal disorders).

Is G40.509 a billable code?

Yes. G40.509 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does G40.509 belong to?

It belongs to category G40 – Epilepsy and recurrent seizures.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.