2026 ICD-10-CM Diagnosis Code G51.4Facial myokymia

AHRQ’s CCSR groups this code into broader clinical categories.

• Facial Nerve Diseases

  diseases of the facial nerve or nuclei. pontine disorders may affect the facial nuclei or nerve fascicle. the nerve may be involved intracranially, along its course through the petrous portion of the temporal bone, or along its extracranial course. clinical manifestations include facial muscle weakness, loss of taste from the anterior tongue, hyperacusis, and decreased lacrimation.

• Hemifacial Spasm

  recurrent clonic contraction of facial muscles, restricted to one side. it may occur as a manifestation of compressive lesions involving the seventh cranial nerve (facial nerve diseases), during recovery from bell palsy, or in association with other disorders. (from adams et al., principles of neurology, 6th ed, p1378)

• Isaacs Syndrome

  a rare neuromuscular disorder with onset usually in late childhood or early adulthood, characterized by intermittent or continuous widespread involuntary muscle contractions; fasciculation; hyporeflexia; muscle cramp; muscle weakness; hyperhidrosis; tachycardia; and myokymia. involvement of pharyngeal or laryngeal muscles may interfere with speech and breathing. the continuous motor activity persists during sleep and general anesthesia (distinguishing this condition from stiff-person syndrome). familial and acquired (primarily autoimmune) forms have been reported. (from ann ny acad sci 1998 may 13;841:482-496; adams et al., principles of neurology, 6th ed, p1491)

• Myokymia

  successive and rapid contractions of motor units associated with chronic nerve injury. the discharges arise from the peripheral aspects of regenerating nerves, and clinically impart a nearly continuous undulation of the body surface overlying the muscle. (adams et al., principles of neurology, 6th ed, p1491)

• Trochlear Nerve Diseases

  diseases of the fourth cranial (trochlear) nerve or its nucleus in the midbrain. the nerve crosses as it exits the midbrain dorsally and may be injured along its course through the intracranial space, cavernous sinus, superior orbital fissure, or orbit. clinical manifestations include weakness of the superior oblique muscle which causes vertical diplopia that is maximal when the affected eye is adducted and directed inferiorly. head tilt may be seen as a compensatory mechanism for diplopia and rotation of the visual axis. common etiologies include craniocerebral trauma and infratentorial neoplasms.

• Dyskinesia with Orofacial Involvement, Autosomal Dominant|DSKOD|FDFM|Familial Dyskinesia and Facial Myokymia

  dyskinesia with orofacial involvement that is inherited in an autosomal dominant pattern.

• Episodic Ataxia Type 1|EA1|Episodic Ataxia with Myokymia

  an autosomal dominant form of episodic ataxia caused by mutation(s) in the kcna1 gene, encoding potassium voltage-gated channel subfamily a member 1.

• KCNA1 wt Allele|AEMK|EA1|HBK1|HUK1|KV1.1|MBK1|MK1|MK1, Mouse, Homolog of Gene|Potassium Channel, Voltage Gated Shaker Related Subfamily A, Member 1 Gene|Potassium Channel, Voltage-Gated, Shaker-Related Subfamily, Member 1 Gene|Potassium Voltage-Gated Channel Subfamily A Member 1 wt Allele|Potassium Voltage-Gated Channel, Shaker-Related Subfamily, Member 1 (Episodic Ataxia with Myokymia) Gene|RBK1|Voltage-Gated Potassium Channel Protein Kv1.1 Gene

  human kcna1 wild-type allele is located in the vicinity of 12p13.32 and is approximately 8 kb in length. this allele, which encodes potassium voltage-gated channel subfamily a member 1 protein, is involved in membrane excitation via potassium ion transport in the kidney and central nervous system. mutations in the gene are associated with episodic ataxia/myokymia syndrome.

• Myokymia

  a disorder characterized by involuntary and irregular muscle contractions not associated with muscle weakness or atrophy. it most often affects facial muscles. it may be localized or generalized.

Facial Injuries and Disorders

Face injuries and disorders can cause pain and affect how you look. In severe cases, they can affect sight, speech, breathing and your ability to swallow. Fractures (broken bones), especially in the bones of your nose, cheekbone and jaw, are common facial injuries.

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