Facial nerve neuritis (Bell's palsy, post-traumatic neuropathy)

Attention! Please do not confuse the diagnosis of "facial nerve neuritis" described in this article with the diagnoses of "trigeminal neuralgia" and "trigeminal neuritis".

Facial nerve neuritis (Bell's palsy, post-traumatic neuropathy)

Neuritis of the facial nerve is inflammation with an impaired integrity of the facial nerve or its myelin sheath with motor, sensory and autonomic changes in the area of innervation of facial muscles and facial distortion.

Neuritis of the facial nerve occurs due to damage to the sheath of the facial nerve or an impaired integrity. This damage or inflammation of the facial nerve can occur anywhere:

• in the cranial cavity
• when passing through the bone canal (in the styloid opening)
• on the face

Superficial branches of the facial nerve - temporal, zygomatic, buccal, mandibular and cervical.

Neuritis of the facial nerve occurs with inflammation as a result of infection (herpes, otitis media), with trauma to the bones of the base of the skull as a result of TBI, compression by a tumor of the cerebellar angle (brain, cranial nerves) or aneurysm of the vertebral artery, poisoning, etc.

According to the mechanism of occurrence of facial nerve neuritis, one can distinguish:

• post-traumatic neuritis of the facial nerve (fracture of the temporal bone pyramid during TBI, brain surgery, plastic surgery for a circular facelift)
• neuritis of the facial nerve as a result of compression of the nerve by a brain tumor in the cranial cavity
• infectious neuritis of the facial nerve (Bell's palsy caused by the influenza or herpes virus)
• toxic neuritis of the facial nerve

Most often in neurological practice, there is neuritis of the facial nerve caused by a viral infection. Such a virus that causes a picture of paresis or paralysis of the facial muscles of the face with neuritis of the facial nerve is the herpes virus. In this case, most often, neuritis of the facial nerve and the paralysis of the muscles of the face itself is one-sided.

The tendency to develop neuritis of the facial nerve with a viral infection (cold, hypothermia, general depletion of the body) is primarily due to the anatomical feature of its location - the narrowness of the bony canal, in which the facial nerve runs on the way out of the cranial cavity.

Paresis or paralysis of facial muscles with neuritis of the facial nerve occurs on the side of the nerve damage.

The herpes virus nests in the myelin sheath of the facial nerve. In the active phase of its division, the herpes virus damages the myelin sheath of the facial nerve, causing its edema (part of the inflammatory response to a viral infection of the body as a whole) - this condition is called facial nerve neuritis or Bell's palsy.

As a result of neuritis of the facial nerve, there is an impaired conduction of a nerve impulse from the brain to the muscles of the face, which is manifested by paresis or paralysis of these muscles.

Depending on the level and type of damage to the facial nerve, the patient with neuritis of the facial nerve will have the following manifestations and complaints: movement disorders (paresis, paralysis) in one or another facial muscle or muscle group with the inability to close the eyes, numbness of the lateral surface of the tongue.

With neuritis of the facial nerve, the patient cannot close the eye (the eyeball turns upward, exposing the sclera (Bell's phenomenon) because the eyelids do not close), wrinkle the forehead, and show teeth (when trying to smile) on the affected side. In this case, the lower eyelid and lower lip will be slightly lowered.