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ICD-10-CM 2027 diagnosis code

G51.4Facial myokymia

✓ Billable / specific

G51.4 is a valid, billable ICD-10-CM code for facial myokymia. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Myokymia.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About G51.4

G51.4 is the ICD-10-CM diagnosis code for facial myokymia. It belongs to category G51 (facial nerve disorders), block G50-G59 (nerve, nerve root and plexus disorders) and chapter 6 (diseases of the nervous system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within G51 (facial nerve disorders), G51.4 is specifically for facial myokymia. Related codes cover Bell's palsy (G51.0), geniculate ganglionitis (G51.1), Melkersson's syndrome (G51.2), Clonic hemifacial spasm (G51.3), other disorders of facial nerve (G51.8) and disorder of facial nerve, unspecified (G51.9).

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 073 (Cranial and Peripheral Nerve Disorders with MCC, relative weight 1.5779) and DRG 074 (Cranial and Peripheral Nerve Disorders without MCC, relative weight 1.0173), 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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 351.8 (other facial nerve disorders).

Notes that apply from higher levels

Instructions written at a parent level also apply to G51.4.

› From G51 Facial nerve disorders
Includes
  • disorders of 7th cranial nerve

Broader instructions also apply from G50-G59 Nerve, nerve root and plexus disorders and Chapter 6: Diseases of the nervous system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to G51.4.

Codes whose notes reference G51.4

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 351.8Other facial nerve disordersapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about G51.4

Is G51.4 billable?

Yes. G51.4 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can G51.4 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict G51.4 as a principal diagnosis.

Is G51.4 a CC or MCC?

No. G51.4 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does G51.4 group to?

G51.4 is used in the MS-DRG v44.0 logic for MS-DRG 073 (Cranial and Peripheral Nerve Disorders with MCC) and MS-DRG 074 (Cranial and Peripheral Nerve Disorders without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for G51.4?

The CMS General Equivalence Mappings map G51.4 to ICD-9-CM 351.8.