Causes of facial nerve paralysis

Facial nerve paralysis is what we often call facial palsy. This is a relatively serious disease, also known as crooked mouth. It often causes a greater impact on facial appearance and causes crooked mouth and eyes. Sometimes some simple facial expressions cannot be completed. There are many causes of facial nerve paralysis, the most important of which are neuritis and peripheral facial neuritis.

Causes of facial nerve paralysis

There are many causes of facial neuritis. Clinically, it can be divided into central facial neuritis and peripheral facial neuritis according to the site of damage. The lesions of central facial neuritis are located in the corticobulbar tract between the facial nerve nucleus and the cerebral cortex, and are usually caused by cerebrovascular disease, intracranial tumors, brain trauma, inflammation, etc. Peripheral facial neuritis lesions occur in the facial nerve nucleus and facial nerve.

The common causes of peripheral facial neuritis are: ① infectious lesions, mostly caused by the activation of viruses lurking in the sensory ganglia of the facial nerve; ② ear diseases, such as otitis media; ③ autoimmune reactions; ④ tumors; ⑤ neurogenic; ⑥ trauma; ⑦ poisoning, such as alcohol poisoning, long-term exposure to toxic substances; ⑧ metabolic disorders, such as diabetes, vitamin deficiency; ⑨ vascular insufficiency; ⑩ congenital facial nerve nuclear dysplasia.

Clinical manifestations

The symptoms are often paralysis of the facial expression muscles on the affected side, disappearance of forehead wrinkles, widening of palpebral fissure, flattening of nasolabial groove, and drooping corners of the mouth. When smiling or showing teeth, the drooping corners of the mouth and facial crookedness are more obvious. The affected side should not frown, knit brows, close eyes, puff out air, or purse lips. When puffing out cheeks and whistling, air leaks out because the lips on the affected side cannot close. When eating, food residues often remain in the buccal space on the affected side, and saliva often flows down from that side. Because the lacrimal points are everted with the lower eyelid, the tears cannot be drained normally and overflow.

Most facial paralysis caused by facial neuritis is unilateral, and is more common on the right side. Most patients often suddenly find that one side of the cheek has difficulty moving and the corner of the mouth is crooked when washing their face or rinsing their mouth in the early morning. Some patients may have taste disorders in the front 2/3 of the tongue, hearing hypersensitivity, etc.

Peripheral facial neuritis caused by trauma can be divided into two types: early-onset (facial paralysis occurs immediately after injury) and delayed-onset (facial paralysis occurs 5 to 7 days after injury). Based on the early or late occurrence and degree of facial paralysis after injury, electrical excitation and electromyography examinations can be used to evaluate the extent of facial nerve damage and determine the prognosis.