How much do you know about the causes of facial paralysis?

Facial nerve paralysis (facial palsy) is just a symptom. There are many causes of this disease (no less than a hundred reported in professional literature). Try to find out as much as possible before treatment. Just like a fever, a common cold can also cause a fever, but it can heal itself. If the fever caused by SARS pneumonia is not treated in time, it may be fatal. Fever cannot be solved with a single antipyretic drug, and the same is true for facial nerve paralysis.

After the causes of some diseases are identified, useless treatments are meaningless and will only increase the pain of the patient; and some special causes may be life-threatening if they are not eliminated. Our facial nerve team routinely sees patients with facial nerve paralysis, and the following types are more common: (The facial paralysis described in this article does not include central facial paralysis caused by cerebrovascular disease)

① Congenital diseases

This type of disease is rare. We have encountered several cases of congenital facial nerve aplasia or dysplasia, and one case of Möbius syndrome. These congenital diseases will cause hemi- or bilateral facial nerve aplasia immediately or gradually after birth, and there may also be deformities in other parts of the body. There is basically no drug that can treat it. Plastic surgery can be considered for severe deformities.

② Trauma

Forceps injuries during birth, children falling from bicycles and roofs, being hit by old TVs, car accidents and beatings in adults, etc. Blunt injuries are more common in adult trauma, where external forces cause fractures of bones around the facial nerve and squeeze the facial nerve. Some injuries are caused by sharp objects directly damaging the facial branches of the facial nerve, such as knives, dog bites, broken bottles, etc. Traumatic diseases often have a clear history of injury or traces of injury, and the specific treatment has a lot to do with the time after the injury. It is said that movie star Sylvester Stallone had facial paralysis when forceps were used during childbirth, and one corner of his mouth was still crooked when he smiled many years later.

③Infectious diseases

Herpes zoster and otitis media are the most common. Among them, herpes zoster virus can not only cause facial paralysis, but also deafness and vestibular nerve dysfunction in severe cases. It is a more aggressive viral pathogenic factor. Antiviral and hormone shock treatment is required in the early stage, and facial nerve decompression surgery is required for severe cases. The sequelae are more common than Bell’s palsy mentioned later.

Middle ear cholesteatoma is the most dangerous. I encountered a patient in Inner Mongolia whose middle ear cholesteatoma invaded the brain. In addition to facial nerve paralysis, he also suffered from coma and high intracranial pressure. After hospitalization, the neurosurgery department performed a craniotomy to save his life. Basically, patients with cholesteatoma need surgical treatment, and there is no room for maneuver.

④Systemic factors

This type of factors can be further divide into dozens of types in professional books. The one I come into contact with most is facial nerve paralysis in pregnant and postpartum women. Women’s hormone levels, immune system, microcirculation, coagulation, etc. during pregnancy and postpartum period are very different from those before pregnancy. Facial nerve paralysis is very common, especially one month before and one month after delivery. Affected by the fetus and breastfeeding factors, the use of steroid hormones in drugs is greatly restrict. And treatment is more difficult.

⑤ Tumor factors

This type of disease is relatively rare and is divide into facial nerve paralysis caused by tumors of the facial nerve itself (facial nerve fibroma, facial nerve sheath tumor) and facial nerve paralysis caused by compression or direct destruction of tumors in the area surrounding the facial nerve (external, middle, inner ear tumors, parotid gland tumors). The cholesteatoma mentioned above should also be classified as a tumor factor in the view of most ear doctors today. The key to the treatment of tumor factors is early detection, picking out these patients from the so-call “Bell’s palsy”, and performing surgery when the tumor is small, and the facial nerve function may still be restore. If the size is too large, not only will the facial nerve function be unable to recover, but the brain tissue damage mentioned above will also be very dangerous.

⑥ Iatrogenic factors

After the facial nerve is emitted from the brain, it enters the bones of the middle ear, travels about 3 cm, and then comes out from behind the ear to enter the parotid gland, gradually dispersing to control the facial muscles in different areas. Any invasive medical operation on this pathway may damage the facial nerve. The most common of which are otitis media surgery and parotid gland surgery. There are many specific reasons for the damage cause by surgery. Which I have introduce in related popular science articles, so I will not go into details in this article. For mild injuries, the facial nerve function can usually recover on its own. While severe injuries require facial nerve anastomosis, transplantation and other operations.

⑦ Idiopathic factors

Among patients with facial nerve paralysis, a considerable number do not have the above-mention pathogenic factors, and are collectively referred to as Bell’s palsy. Colds and wind, which are well known to the Chinese, are not recognized pathogenic factors. Bell’s palsy has a high degree of self-healing ability, and the vast majority of patients can recover significantly. However, 15% of patients still do not recover well even with the use of various drug treatments. Even worse, they will be left with very serious sequelae. The focus of Bell’s palsy is to distinguish which are mild cases. Which are severe cases, and which are not Bell’s palsy at all but hidden tumor diseases.。

The diagnosis of the cause of facial nerve paralysis cannot be hasty. It requires a combination of various examinations to draw a final conclusion. I have met many patients with facial nerve tumors or cholesteatoma. The symptoms at the time of onset are the same as those of ordinary facial nerve paralysis. Even local CT and MRI have not been discover in time They are often torture by various folk remedies for months. Diseases with different causes cannot be treat in one way. Before treating the disease, it is best to ask the doctor, what is the problem with my facial nerve?