Hemifacial spasm: What you need to know

 Hemifacial spasm is a condition in which the muscles contract in tics or twitches on one side of the face, usually the left. People do not have control over these spasms, and very often they continue even during sleep.

Hemifacial spasm is usually not painful and not considered a health hazard. In advanced cases, however, the eyes may remain squeezed shut for long enough to become dangerous when driving, for example.

Both men and women can develop these facial twitches, but women, especially middle-aged and older women, develop hemifacial spasm at about twice the rateTrusted Source of men. The condition is also somewhat more common in Asian people.

Types

Hemifacial spasm is different from other nerve and muscle conditions affecting the face because it tends to affect only one side of the face.

However, there are differences between what is considered typical for hemifacial spasm and other forms of the condition.

A study of 215 people being examined for hemifacial spasm found that:

• 62 percent were most likely caused by a vein putting pressure on the facial nerve
• 18 percent had tics that mimicked hemifacial spasm but were not actually examples of the disease
• 11 percent were due to Bell’s Palsy
• 6 percent were the result of injuries to the facial nerve
• 2 percent were linked to hereditary causes

Fewer than 1 percent of cases were caused by direct damage to nerves or the brain’s circulatory system

Symptoms

The first sign of hemifacial spasm is usually a twitching in the muscles of the left eyelid. These spasms can be strong enough to pull the eye closed and cause tears to form.

If left untreated, the symptoms of hemifacial spasm can become more severe and affect more and more facial muscles. Twitches can affect the muscles of the mouth and pull it to one side.

Over time, all the muscles on one side of the face can be pulled into a permanent frown. Some individuals may develop spasms on both sides of the face.

Ear pain, a “clicking” in the ear, and changes in hearing can also be symptoms of this condition. Hearing loss also sometimes occurs.

Around 13 percent of people taking part in one study reported a loss of hearing. However, this hearing loss did not appear to relate to how serious their hemifacial spasm symptoms were.

Symptoms of hemifacial spasm usually develop when people are between 40 and 50 years of age.

Causes

Hemifacial spasm is caused by irritation to the seventh cranial nerve. This nerve is known as the facial nerve and controls the muscles of the face. It also transmits information about the sense of taste from the tongue and sensations in the ear.

The most frequent source of irritation is a small artery pressing on the facial nerve near the brain stem. Other potential causes include:

• a benign tumor or lesion pressing on the nerve
• abnormal clusters of blood vessels at birth
• nerve injury

Hereditary cases of hemifacial spasm have been identified, although they are not common.

In some cases, hemifacial spasm is the first symptom of multiple sclerosis or MS. When people have MS, their immune system attacks the central nervous system, which results in a wide variety of symptoms.

However, this is extremely rare, with scientific studies showing only 1 to 6 occasions out of several hundred cases in which MS was identified as the cause of a hemifacial spasm.

Although it is rare, doctors still need to check for MS as a possible cause when people under age 40 have a hemifacial spasm.

Source: Medical News Today