What is Bell's palsy and what are its clinical manifestations?

Bell's palsy, also known as idiopathic facial palsy, accounts for about 60% to 75% of all facial paralysis, ranking first among peripheral facial paralysis. 80% can recover completely spontaneously, while 20% have incomplete spontaneous recovery. So what is the cause of Bell's palsy?

Causes

It is not yet clear, but most scholars currently believe that it may be neuritis caused by the herpes simplex virus. There are also vascular factors. Due to spasm of the facial nerve supplying artery, ischemia and hypoxia of the capillary wall, the permeability of the blood vessel wall increases, and the nerves and their fibrous membrane tissues edema.

Clinical manifestations

Most cases are unilateral, occasionally bilateral, and can recur in about 2%. The disease can occur at any age, but is most common in people aged 20 to 40 years old. The incidence rate in men is higher than that in women. The onset is sudden, with symptoms such as difficulty in cheek movement, crooked corners of the mouth, drooling, hearing hypersensitivity, and taste disorders. On examination, the face was asymmetrical and showed signs of peripheral facial paralysis. During otoscopy, only in a few cases can the swollen and congested chorda tympani nerve be seen through the tympanic membrane. Depending on the location of the lesion, there is often loss of the stapedius muscle reflex and taste disturbance in the anterior 2/3 of the tongue. Mastoid CT scan is normal, and MRI examination may show swelling of the facial nerve.

Clinical diagnosis

It can only be confirmed through a comprehensive medical history analysis and detailed examination, and after excluding diseases such as suppurative otitis media, ear tumors, facial nerve tumors or congenital cholesteatoma. If there is no sign of functional recovery 6 months after the onset of facial paralysis, the possibility of other lesions should be considered.

『Treatment and health care』

Seek medical attention promptly and receive treatment as early as possible. If you find sudden symptoms such as stiff cheek movements, crooked mouth corners, drooling, auditory hypersensitivity, taste disorders, etc., you should seek medical attention promptly to get a clear diagnosis, which will facilitate timely treatment. After diagnosis, treatment should be started as soon as possible, but the efficacy of drugs is difficult to estimate. Commonly used drugs include glucocorticoids, antiviral drugs, vasodilators, vitamins B1, B12 and ATP, etc.

Physical therapy can be used, such as infrared and massage, which can enhance local blood circulation, promote nerve regeneration, maintain muscle tension, and prevent muscle atrophy.

Hyperbaric oxygen therapy is feasible, which can increase blood oxygen saturation and reduce the damage caused by facial nerve ischemia and hypoxia. Try blockade therapy. Procaine blockade of the stellate ganglion or cervical sympathetic ganglion has the effect of dilating the facial nerve blood vessels.

Because the eyelids cannot close, topical medication should be used. Eye pads can prevent corneal dryness and dust damage, thereby protecting the cornea.

If the patient has complete facial paralysis, the facial nerve electrogram shows that the facial nerve degeneration is greater than 90%, the facial electromyogram shows that the autonomous action potential disappears, and the course of the disease does not exceed one month, high-level facial nerve decompression via the middle cranial fossa approach or full facial nerve decompression via the middle cranial fossa and mastoid combined approaches can be considered.