Bell's Facial Nerve Palsy
Definition: Facial hemiparesis as a result of a lesion of the facial cranial nerve VII (seven).
Causes Although the true aetiology of Bell's Palsy is not fully understood a number of well postulated theories may be considered. These are; a viral infection such as HSV-I (Herpes Simplex Type-) being reactivated, a demyelinating polyneuropathy, diabetes mellitus, severe hypertension, HIV infection, and some malignancies. The symptoms become apparent within a couple of days.
Examination The patient often presents with droopiness in the facial muscles affecting one side of the face, both the upper and lower parts. Some patients may experience pain around the ear a few days before onset of symptoms. The patient is unable to frown or raise their eyebrow on the affected side, reduced tear production, dribbling due to sagging of the mouth, hyperacusis, reduced corneal reflex due to motor component paralysis (sensation to the cornea from trigeminal nerve remains intact) and, inability to blow up cheeks or whistle.