ICD-10 Code G51.33 – Clonic hemifacial spasm, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G51.33 – Clonic hemifacial spasm, bilateral
What it is
This code identifies involuntary, repetitive clonic spasms affecting facial muscles on both sides of the face. It is used when documentation specifies bilateral hemifacial spasm rather than a unilateral or unspecified facial spasm.
Clinical signs
Typical findings include sudden, brief facial muscle contractions that recur in a clonic pattern and involve both sides. Clinical features vary; refer to documentation for laterality, affected muscles, and any associated neurologic findings.
When to use this code
Use G51.33 when the provider documents bilateral clonic hemifacial spasm as the diagnosis. Apply it for encounters focused on evaluation, follow-up, or symptom management when the record clearly states both sides are involved. If laterality is not documented, check documentation before coding.
Do not use for
Do not use this code for unilateral hemifacial spasm, nonspecific facial twitching, or other movement disorders without bilateral clonic facial involvement. Check documentation if the record describes facial weakness, tics, or seizures instead.
Coding tip
Confirm that “bilateral” and “clonic hemifacial spasm” both appear in the provider’s note before assigning G51.33.