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Bell's palsy occurs when the nerve that controls the facial muscles
is swollen, inflamed, or compressed, resulting in facial weakness or
paralysis. The etiology of this form of facial palsy is unknown
and therefore exactly what causes this damage is also unknown.
Many scientists believe that a viral infection such the common
cold sore virus, herpes simplex, causes the disorder.
It is thought
that the 7th Cranial nerve (VII) which supplies the face, swells and
becomes inflamed in reaction to an infection, causing pressure
within the Fallopian canal, the narrow 'tunnel' in the skull
through which the facial nerve passes in a somewhat tortuous route.
As the nerve swells, it compresses against the inside of the
Fallopian canal and as a result, the nerve is unable to
function.
Bell's Palsy has also been associated with herpes, mumps,
influenza or a flu-like illness, headaches, chronic middle ear
infection, high blood pressure, diabetes, tumors, Lyme disease,
tuberculosis, trauma such as skull fracture, facial injury and even
in some instances, dental work, if the facial nerve is damaged or
frozen during injection.
During pregnancy, Bell's palsy is sometimes associated with
pre-eclampsia,
a condition that affects women at an advanced stage of pregnancy,
noted by high blood pressure, swelling of the ankles and protein in
the urine.
Bell's palsy is also more rarely associated with serious neurological
conditions such as Guillain-Barre syndrome, neurosarcoidosis and
multiple sclerosis. |
