Bell's palsy

Bell's palsy

Definition  :

Bell's palsy causes sudden weakness in your facial muscles. This makes half of your face appear to droop. Your smile is one-sided, and your eye on that side resists closing.

Bell's palsy, also known as facial palsy, can occur at any age. The exact cause is unknown, but it's believed to be the result of swelling and inflammation of the nerve that controls the muscles on one side of your face. It may be a reaction that occurs after a viral infection.

For most people, Bell's palsy is temporary. Symptoms usually start to improve within a few weeks, with complete recovery in about six months. A small number of people continue to have some Bell's
palsy symptoms for life. Rarely, Bell's palsy can recur.

Symptoms:

Signs and symptoms of Bell's palsy come on suddenly, and may include:

• Rapid onset of mild weakness to total paralysis on one side of your face — occurring within hours to days — making it difficult to smile or close your eye on the affected side
• Facial droop and difficulty making facial expressions
• Pain around the jaw or in or behind your ear on the affected side
• Increased sensitivity to sound on the affected side
• Headache
• A decrease in your ability to taste
• Changes in the amount of tears and saliva you produce

In rare cases, Bell's palsy can affect the nerves on both sides of your face.

When to see a doctor
Seek immediate medical help if you experience any type of paralysis because you may be having a stroke. Bell's palsy is not caused by a stroke. See your doctor if you experience facial weakness or drooping, to determine the underlying cause and severity of the illness.


Causes:

Although the exact reason Bell's palsy occurs isn't clear, it's often linked to exposure to a viral infection. Viruses that have been linked to Bell's palsy include the virus that causes:

• Cold sores and genital herpes (herpes simplex)
• Chickenpox and shingles (herpes zoster)
• Mononucleosis (Epstein-Barr)
• Cytomegalovirus infections
• Respiratory illnesses (adenovirus)
• German measles (rubella)
• Mumps (mumps virus)
• Flu (influenza B)
• Hand-foot-and-mouth disease (coxsackievirus)

With Bell's palsy, the nerve that controls your facial muscles, which passes through a narrow corridor of bone on its way to your face, becomes inflamed and swollen — usually related to a viral infection. Besides facial muscles, the nerve affects tears, saliva, taste and a small bone in the middle of your ear.

Complications:

Although a mild case of Bell's palsy normally disappears within a month, recovery from a case involving total paralysis varies. Complications may include:

• Irreversible damage to your facial nerve
• Misdirected regrowth of nerve fibers, resulting in involuntary contraction of certain muscles when you're trying to move others (synkinesis) — for example, when you smile, the eye on the affected side may close
• Partial or complete blindness of the eye that won't close, due to excessive dryness and scratching of the cornea, the clear protective covering of the eye

Treatments and drugs:

Most people with Bell's palsy recover fully — with or without treatment. There's no one-size-fits-all treatment for Bell's palsy, but your doctor may suggest medications or physical therapy to help speed your recovery. Surgery is rarely an option for Bell's palsy.
Medications
Commonly used medications to treat Bell's palsy include:

• Corticosteroids, such as prednisone, are powerful anti-inflammatory agents. If they can reduce the swelling of the facial nerve, it will fit more comfortably within the bony corridor that surrounds it. Corticosteroids may work best if they're started within several days of when your symptoms started.
  
• Antiviral drugs, such as acyclovir (Zovirax) or valacyclovir (Valtrex), may stop the progression of the infection if a virus is known to have caused it. This treatment may be offered only if your facial paralysis is severe.

Physical therapy
Paralyzed muscles can shrink and shorten, causing permanent contractures. A physical therapist can teach you how to massage and exercise your facial muscles to help prevent this from occurring.

Surgery
In the past, decompression surgery was used to relieve the pressure on the facial nerve by opening the bony passage that the nerve passes through. Today, decompression surgery isn't recommended. Facial nerve injury and permanent hearing loss are possible risks associated with this surgery.
In rare cases, plastic surgery may be needed to correct lasting facial nerve problems.