ICD-10 code for grand mal seizure

The ICD-10-CM code for grand mal seizure is G40.409 (Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus). The official index lists 6 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on G40.409.

Within G40.40, choose G40.409 (without status epilepticus) only when documentation doesn't support a more specific option: with status epilepticus (G40.401).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, relative weight 5.7444), DRG 100 (Seizures with MCC, relative weight 1.9233) and DRG 101 (Seizures without MCC, relative weight 0.8952), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.