ICD-10 Code G51.39 – Clonic hemifacial spasm, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G51.39 – Clonic hemifacial spasm, unspecified
What it is
Use this code for an involuntary, repetitive clonic spasm affecting one side of the face. It identifies a hemifacial movement disorder when the record does not specify a more detailed cause or subtype.
Clinical signs
Typical findings include brief, repeated twitching of facial muscles on one side, often involving the eyelid and mouth. Clinical features vary; refer to documentation.
When to use this code
Assign G51.39 when the provider documents clonic hemifacial spasm and does not identify a more specific diagnosis. Use it for unilateral facial spasms recorded in neurology, primary care, or specialty notes when laterality or etiology is not further clarified.
If the chart only says “facial twitching” or “spasm,” confirm that hemifacial spasm is intended before coding. Check documentation when the note suggests another facial nerve disorder or a different movement condition.
Do not use for
Do not use this code for generalized muscle spasms, facial pain, or Bell palsy without documented hemifacial spasm. Do not code it when a more specific hemifacial spasm diagnosis is documented.
Coding tip
Verify that the provider specifically documents hemifacial spasm, because nonspecific “twitching” usually needs clarification.