Peripheral facial nerve palsy is a condition in which the facial expression muscles on one or both sides of the face are paralyzed, resulting in the inability to frown, frown, close the eyes, show the teeth, or puff out the cheeks on the affected side. The result of untreated facial nerve palsy is disfigurement.
I. Etiology
The most common cause is facial neuritis, also known as Bell’s palsy, which accounts for more than 95% of clinical facial nerve palsy. The cause of facial neuritis is not completely clear, and may be related to the following factors.
1, viral infection
It is an important causative factor, although viruses are rarely isolated. The majority of the short-term or persistent pain behind the ear on the affected side seen clinically is due to viral infection.
2. Autoimmune abnormalities
Immune abnormalities predispose the facial nerve to inflammatory changes. For those patients who have recurrent facial neuritis, it is a type dominated by intrinsic factors.
3.Tumor
Tumors of the pontocerebellar angle, auditory neuroma, other tumors of the head and neck and after facial nerve decompression may damage the facial nerve.
4.Brainstem hemorrhage or infarction
Hemorrhage or infarction located in and near the facial nerve of the brainstem sometimes leads to unilateral or bilateral peripheral facial nerve palsy.
5.Craniocerebral trauma
Different segments of the facial nerve may be injured after skull base fracture or temporal side trauma.
6.Septic inflammation
Otitis media, mastoiditis, parotitis or inflammatory infections of the auricle and root of the ear can affect the trunk or branches of the facial nerve and produce lesions.
The onset of the disease is rapid, mostly on one side of the face, with no obvious seasonality, mostly in winter and summer, and can be seen at any age, but is more likely to occur in young adults aged 20-40, with little difference in gender.
Diagnosis
Most of the patients have acute onset, or without any signs and symptoms, the affected side of the corner of the mouth is found to be leaking in the early morning when brushing teeth, and the food is stuck. 70% of the patients reach the peak of the disease within 1-3 days, and a few reach the peak within 5 days, some patients suddenly appear herpes on the affected side of the ear and aggravate around 2 weeks after treatment.
III. Clinical symptoms
1. Acute onset, with peak symptoms in a few hours or days. The disease may be accompanied by pain in the mastoid area behind the ear, in the ear or at the angle of the jaw at the beginning.
2, one side of the facial expression muscle paralysis as the prominent manifestation, the corner of the mouth is crooked, salivation, speech leakage, cheek and whistle leakage, food stagnation between the diseased side of the teeth and cheeks.
3.It may be accompanied by loss of taste, saliva reduction, auditory hypersensitivity, pain in the affected mastoid area, hypoesthesia of the earwax and external auditory canal, and herpes of the external auditory canal or tympanic membrane.
The frontal lines on one side of the face disappear, the lid fissure becomes larger, the nasolabial fold becomes shallower and flatter, the corners of the mouth on the diseased side droop, and the corners of the mouth are crooked to the healthy side when showing the teeth, and the affected side leaks air when doing cheek puffing and whistling. Inability to raise the forehead and frown, weak or incomplete eyelid closure. When the eyes are closed, the eyeballs turn upward and outward, revealing the white sclera, which is called Bell’s sign.
Auxiliary examinations
1. Neurophysiology
It is meaningful to determine the prognosis of facial neuropathy, including excitation threshold measurement, complex muscle action potential wave amplitude measurement and facial nerve conduction velocity measurement.
2.Imaging examination
In order to exclude posterior cranial fossa lesions such as pontocerebellar horn tumor, skull base occupying lesion, vascular disease of cerebral bridge, some patients need to do head MRI or CT examination.
3.Laboratory examination
4.Blood routine examination
Most of the blood leukocyte count and classification are normal, but some patients who have used glucocorticoids will have elevated total leukocyte count. Lymphocytes are increased and neutrophils are decreased in patients with viral infection.
5.Biochemical examination
If fasting blood glucose is elevated, whether diabetes is diagnosed, the use of glucocorticosteroids should be noted to affect blood glucose.
6.Immunological examination
For patients who clearly have the appearance of herpes or the affected side of the neck and occipital pain is obvious without the appearance of herpes, two or more episodes of facial nerve palsy, routine immunological testing.
7.Cerebrospinal fluid examination
For suspected cranial nerve type Grin-Barre syndrome, showing simultaneous peripheral paralysis of both facial nerves, lumbar puncture cerebrospinal fluid examination should be done.
V. Assessment
Facial nerve grading assessment.
1.Diagnostic criteria for localization
(1) Damage to the geniculate ganglion and above.
(2) below the geniculate ganglion to the stapedius muscle branch.
(3) below the stapedius muscle branch to the bulbar cord.
(4)below the tympanic cord (including the stapedial foramen and beyond).
2.Grading evaluation criteria
According to the 10 items of forehead lifting, frowning, eye closing, nose shrugging, zygomatic muscle weakness, nasolabial furrow depth, whether or not to puff cheeks, whether or not to whistle, showing teeth exposure, lower lip drop amplitude, divided into normal (10 points), weaker than the healthy side (7.5 points, 5 points, 2.5 points), disappearance (0 points), each item is scored, and the total score is used as the basis for grading.
VI. Treatment
1.General principles
Early detection, early treatment; subjective examination for grading; necessary laboratory tests; avoid primary diseases aggravating the dysfunction of the facial nerve innervation area, avoid strong wind blowing directly on the affected side.
2.Grading treatment principles
(1) FP4 segment 1-3 grade is a mild evidence, apply glucocorticoid, improve blood circulation, B vitamin class, physiotherapy, acupuncture, generally in about 2-3 weeks can recover.
(2) Those with FP1-4 segment 4-6 grade, which belong to facial neuritis, need adequate anti-inflammatory, dehydration, anti-viral, improving blood circulation, nerve nutrition and other methods to reduce edema of facial nerve in the bony cavity in the early stage. The acute and recovery periods can be combined with different physical therapy and acupuncture. Non-facial neuritis facial nerve palsy, mostly after surgery or treatment of the primary disease into the recovery period, mostly treated with acupuncture, physiotherapy and neurotrophic drugs.
3.Stage treatment principles
(1) Acute stage (1-7 days)
The treatment is mainly based on anti-inflammation, improving blood circulation, reducing facial nerve canal edema and nerve damage; drugs and physiotherapy can be carried out simultaneously. For facial neuritis caused by viral infection, antiviral drugs are required.
(2) Recovery period
(1) Early recovery period (7-14 days) starts with neurotrophic drugs, Chinese herbal medicine, physiotherapy and electroacupuncture; facial nerve functional training.
In the middle of the recovery period (15-28 days), the aforementioned methods will be continued for the lighter cases, while the heavier cases must be treated with low-frequency pulse electrical stimulation, local massage, methylcobalamin acupoint injection or injection outside the affected stem mammary foramen.
③Later in the recovery period (after 29 days) most of them can be clinically cured by the above method. In some severe patients, observation is required for 6-9 months, during which multi-path and multi-method treatment can be adopted according to the degree of facial nerve branch injury.
Treatment of sequelae
After the acute and recovery treatment of facial nerve palsy of various types, the function of the affected facial nerve cannot be fully restored within 6 months, and the affected eye may be left with overflowing tears (crocodile tears), facial inversion (crooked corners of the mouth to the affected side, small lid fissures, facial muscle spasm), etc. For these signs and symptoms, it is difficult to produce significant results with various treatments at this time, but botulinum toxin correction treatment can be tried.
For otorhinolaryngology-head and neck surgery, facial nerve decompression and facial nerve anastomosis may be performed; for tearing, ophthalmology may perform lacrimal duct recanalization; for facial muscle spasm, botulinum toxin type A may be used and injected into the spastic muscle target site. However, all of them will inevitably leave sequelae of varying degrees.
VII. Prognosis
About 70% of patients can fully recover, 20% partially recover and 10% poorly recover. Young patients have a good prognosis, while older patients with mastoid pain or combined with diabetes, hypertension, atherosclerosis, myocardial infarction, etc. have a poor prognosis.