The facial nerve courses through a portion of the temporal bone commonly referred to as the facial canal. A popular theory proposes that edema and ischemia results in compression of the facial nerve within this bony canal.
Given the tight confines of the facial canal, it seems logical that inflammatory, demyelinating, ischemic, or compressive processes may impair neural conduction at this site.
ETIOLOGY
situations that produced cold exposure (eg, chilly wind, cold air conditioning, or driving with the car window down) were considered the only triggers to Bell palsy. believe that the herpes simplex virus autoimmune reactions causing the facial nerve to demyelinate, resulting in unilateral facial paralysis , autosomal dominant.
CAUSE:
idiopathic facial paralysis
(HSV) is a common cause of Bell palsy
Symptoms
· Change in facial expression (for example, grimacing)
· Difficulty with eating and drinking
· Drooling due to lack of control over muscles of the face
· Droopy eyelid or corner of mouth
· Dry eye or mouth
· Face feels stiff or pulled to one side
· Facial paralysis of one side of the face, makes it hard to close one eye
· Headache
· Loss of sense of taste
· Pain behind or in front of the ear
· Sensitivity to sound (hyperacusis) on the affected side of the face
· Twitching in face
· Weakness in face
Complications
· Abnormal movements, such as tears when laughing or salivation at the wrong times (synkinesis)
· Change in appearance of the face (disfigurement) from loss of movement
· Chronic problems with taste
· Chronic spasm of face muscles or eyelids
· Damage to the eye (corneal ulcers and infections)