Acute non-suppurative inflammation of the facial nerve within the facial canal (inside the stylomastoid foramen).

bubble_chart Etiology

Peripheral deviation of the mouth is often caused by facial nerve ischemia resulting from local neurovascular spasm and compression due to exposure to cold drafts.

bubble_chart Clinical Manifestations

The onset is sudden, often occurring upon waking from sleep, with one side of the face feeling stiff, numb, and paralyzed, making it impossible to perform actions such as frowning, wrinkling the brow, showing teeth, or puffing out the cheeks. The corner of the mouth deviates toward the unaffected side, with tearing and loss of forehead wrinkles. The nasolabial fold on the affected side becomes shallow or disappears. A few patients may initially experience pain behind the ear, below the ear, or in the face. In severe cases, there may be a reduction or loss of taste in the anterior two-thirds of the tongue on the affected side, as well as hyperacusis.

bubble_chart Auxiliary Examination

1. The X-ray of the internal auditory canal is normal.
2. Electrophysiological examination shows slowed facial nerve MCV and reduced or absent action potential amplitude in facial muscle EMG.

bubble_chart Diagnosis

1. Medical History and Symptoms:

It is more common in young adults, and some patients experience pain in the ipsilateral retroauricular, intraauricular, or mastoid region a few days before onset. The medical history should inquire about predisposing factors such as exposure to cold or wind on the face before onset. Most patients suddenly notice facial immobility or deviation, difficulty in making facial expressions, disappearance of forehead wrinkles, widening of the palpebral fissure, flattening of the nasolabial fold, and drooping of the mouth corner while washing their face in the morning.

1. Peripheral deviation of the mouth is observed, with the affected side unable to perform actions such as frowning, closing the eyes, showing teeth, or puffing the cheeks.
2. If the facial nerve damage above the stylomastoid foramen affects the chorda tympani branch, taste disturbance in the anterior two-thirds of the tongue may occur.
3. Involvement of the stapedius muscle branch may lead to hyperacusis.
4. If the geniculate ganglion is affected, herpes may appear in the external auditory canal, known as (Hunt's syndrome).

bubble_chart Treatment Measures

1. Improve microcirculation, reduce local edema, and nourish nerves. 706 plasma substitute 500ml + citicoline 500mg IV once daily for 7–10 days as a course, prednisone 30–40mg orally once daily, tapered after one week, vitamin B1 30mg orally twice daily, vitamin B12 100–500ug intramuscular injection once daily.
2. Physical therapy: During the acute phase, apply hot compress, infrared radiation, or ultrashort wave therapy near the stylomastoid foramen.
3. Protect the exposed cornea to prevent conjunctivitis by applying eye ointment and wearing an eye patch. Local warmth and massage can help improve local blood circulation and reduce edema.
4. Acupuncture treatment: Focus on the Hand and Foot Yangming channels, supplemented by the Hand and Foot Shaoyang and Taiyang channels. Combine local and distal acupoint selection. For nearby points, use shallow, horizontal, oblique, or penetrating needling. Prescription: Fengchi (GB20), Yangbai (GB14), Zanzhu (BL2), Sibai (ST2), Dicang (ST4), Hegu (LI4), Taichong (LR3). Add Yingxiang (LI20) for flattened nasolabial fold; add Renzhong (GV26) for deviated philtrum; add Chengjiang (CV24) for deviated mentolabial fold; add Yifeng (TE17) for mastoid pain.
5. Chinese medicinals: Pull Aright Powder (Stiff Silkworm 3g, scorpion 3g, giant typhonium rhizome 3g) ground into powder, take 3g daily.
6. Acupuncture: If recovery is delayed after the acute phase, combine with acupuncture (select points such as Jiache (ST6), Dicang (ST4), Ermen (TE21), and Qianzheng (Extra)).

bubble_chart Differentiation

It should be differentiated from other diseases that cause acute peripheral deviation of the mouth, such as mumps or parotid gland tumors, cerebellopontine angle tumors, etc.