Facial Nerve Neuritis: What It Is, Causes, and Signs of Paresis

Yesterday everything was as usual, but today water from a glass runs past the mouth, one eye doesn't close all the way, and half the face seems not to obey. This is how facial nerve neuritis can begin — weakness of facial expression on one side that increases over hours or a couple of days. Next — the facts: what is affected, why it happens, and how to distinguish this condition from a stroke.

Facial Nerve Neuritis: What It Is

Facial nerve neuritis is damage to the seventh cranial nerve, which controls the muscles of facial expression. Its most common form is Bell's palsy, an idiopathic neuropathy of the facial nerve named after the 19th-century Scottish physiologist Charles Bell; it is the most frequent cause of facial muscle paralysis.

Incidence — about 23 cases per 100,000 people per year, or one case per 60–70 people over a lifetime. Weakness is usually unilateral, but occasionally both sides are affected.

How the Facial Nerve Works and What Is Affected in Damage

The nerve runs from the brainstem through a canal in the temporal bone to the facial muscles: it raises the eyebrow, closes the eye, stretches the lips into a smile. When the nerve swells and conduction drops, the muscles receive no commands — the face droops, and the eye on the affected side does not close completely. Along with facial expression, taste, perception of loud sounds, and moistening of the eye and mouth may be affected.

Causes: Viral Infection and a Cold

The exact cause is unknown — Bell's palsy is called idiopathic. Scientists suggest that a viral infection causes the facial nerve to swell and become inflamed; nerve entrapment is often mentioned in everyday speech, but sources cite viral inflammation and nerve edema as the cause, and the exact mechanism remains unknown. The disease is seasonal and can occur after exposure to cold and colds — such neuritis is called a cold-related neuritis. It is more common in pregnant women, people with diabetes, and those who are currently suffering from a cold or flu.

Regarding "does the facial nerve hurt": 1–2 days before weakness, pain behind the ear may appear.

Signs of Facial Nerve Paresis

Paresis is weakness, paralysis is complete absence of movement; with neuritis both occur, from mild to severe. Symptoms appear suddenly and reach their maximum about 48 hours after onset; sometimes weakness increases over several days.

• weakness or immobility of one side of the face;
• drooping eyelid or corner of the mouth, drooling;
• dry eye or constant tearing, dry mouth;
• altered taste, discomfort from loud sounds;
• the eye on the affected side does not close completely.

The prognosis is usually good: three out of four patients improve without treatment, and up to 80% recover within weeks or months. Incomplete paralysis in the first week is a favorable sign.

How to Distinguish Neuritis from Stroke and How the Diagnosis Is Made

The first question in the first hours is whether this is a stroke. In a stroke, in addition to facial distortion, the person cannot raise and hold both arms, and speech is impaired. The diagnosis is made based on the clinical picture, and CT and MRI of the brain are needed to rule out other causes.

This condition is differentiated from diabetes, infections of the middle ear or mastoid process, sarcoidosis, Lyme disease, fractures of the petrous part of the temporal bone, chronic meningitis, and tumors of the cerebellopontine angle. If sarcoidosis is suspected, chest X-ray or CT is performed and the ACE level in the blood is checked. Electromyography distinguishes a temporary conduction defect from an anatomical break in the fibers.

Possible Consequences and When to See a Doctor

See a doctor immediately as soon as weakness of facial expression appears: treatment is more effective if started in the first 72 hours. If there is no improvement after three weeks, a repeat visit is needed. Some people are left with persistent facial weakness, pain in the face, jaw area, and behind the ear, a constantly tearing eye, difficulty eating and drinking, taste changes, and discomfort from loud sounds. Low mood, stress, and anxiety are not uncommon in this situation, and they should also be discussed with a doctor. Usually Bell's palsy occurs once, but occasionally it returns after years.

A distorted face by itself is not a reason to call an ambulance — 103 or 112 are needed immediately if, along with it, the person cannot raise and hold both arms or speech is impaired, slurred, or faltering. These may be signs of a stroke.

This material is for reference and does not replace a doctor's consultation: for weakness of facial expression, the decision is made by a neurologist, not by an article.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer