What causes facial nerve paralysis?

Jeffrey Steitz, MD

Head and Neck Surgery, Otolaryngology

Facial paralysis, where someone becomes unable to move some or all the muscles in one or both sides of their face, can affect people of all ages. Jeffrey Steitz, MD, spoke about what causes facial nerve paralysis, how it’s diagnosed and what treatments might be used depending on the diagnosis.

What happens when you have facial nerve paralysis?

“Facial nerves control muscle function of the face,” said Dr. Steitz. “We each have a left and right facial nerve, which is long, complex and connects the brain to the facial mimetic muscles.”

Most of the time, paralysis occurs when there is damage to the facial nerve or pressure on it that disrupts the ability of the nerve and brain to communicate with the facial muscles. The damage could be located in the face itself or at some point along the pathway to the brain.  The most common site where damage occurs is the parotid gland and inner ear.

What causes facial nerve paralysis?

“The most common cause of facial paralysis is what we call idiopathic,or more commonly known as Bell’s Palsy,” said Dr. Steitz. “In Bell’s palsy, often one side of the face begins to droop and the person’s smile might be one-sided. They may have trouble getting their eye on the affected side to blink.  This is thought to be related to viral illness or some other unknown cause.”

This weakness is usually temporary and will improve over the course of weeks. Facial paralysis may also be related to viral infection, including the shingles virus, or related to pressure coming from facial tumors that could develop along the nerve itself. Tumors, such as acoustic neuromas developing alongside or near the nerve, can also press on or invade the nerve and cause paralysis.

Bell’s palsy is generally painless, but paralysis caused by the shingles virus typically involves some pain and discomfort, with sores on or in the ear on the affected side. If the facial paralysis is caused by tumors, such as facial schwannomas or hemangiomas which generally grow slowly, the weakness and paralysis will occur over long periods of time.

How is the cause of facial paralysis diagnosed?

“Discovering the cause of facial paralysis usually involves ruling out what isn’t the cause first,” said Dr. Steitz. “First we tend to rule out the most concerning causes such as tumors or strokes.  There is no specific lab test that tells us the cause of facial paralysis, but some lab studies may be useful. Your medical team may, in some cases, decide to test your facial nerve function using a noninvasive test called the ENOG or EMG.”

Facial paralysis caused by the shingles virus, known as Ramsey Hunt syndrome, is usually diagnosed using a physical examination and potentially blood tests. Tumors that may be causing facial paralysis are usually diagnosed because of other symptoms that might be present, like loss of balance, hearing loss or pain. In this case, CT scans, an MRI or biopsies may be needed.

How is facial paralysis treated?

“Bell’s palsy tends to improve with time, and so the typical treatment is really time to allow for recovery, combined with oral steroids to help with the inflammation,” said Dr. Steitz. “Eye treatment might be needed to prevent eye complications as well.”

People with a complete facial paralysis caused by Bell’s palsy are at a higher risk for a long-standing weakness of facial movement, due to the way the facial nerve swells and becomes compressed against nearby bone. In this case, surgery removing the bone from this narrow portion of the nerve can improve long-term improvement to facial movement, but the surgery needs to be performed within two weeks of the onset of complete paralysis. It also involves specialized electrical tests that help verify how extreme injury to the facial nerve is.

Ramsey Hunt syndrome, where the shingles virus causes facial paralysis, is typically treated with oral steroids to calm inflammation, antiviral medications to help fight off the virus itself and time for recovery.

Treating facial paralysis caused by the development of tumors depends on the type of tumor, whether it’s cancerous or benign, how large it is, what location it’s found in, whether other areas are also affected and your overall health. Treatment options could include surgery, radiation, observation or other options depending on your specific situation.

Can surgery help with facial paralysis?

Permanent or longstanding facial paralysis can be improved regardless of the cause.  We tend to break surgical procedures into two major categories, static and dynamic reanimation.  Static procedures are geared toward lifting the face, lip and eyelids into a more natural anatomic position.  This is typically achieved with the following surgical procedures:

• Tightening of the lower eyelid
• Upper eyelid gold or platinum weight placement
• Brow lift
• Static facial sling to lift the lower face upwards, similar to a facelift.

Dynamic facial reanimation is performed to try and reproduce natural facial movement.  These surgeries are primarily about re-activating the facial nerve or bringing in new muscles to improve facial symmetry and mobility.  There are some risks and potential side effects after the surgery, which your medical team will speak with you about when deciding whether to pursue this treatment.