Facial palsy may follow skull fracture or facial nerve laceration near the stylomastoid foramen, and is also an uncommon complication of middle-ear surgery and superficial parotidectomy. An extensive cholesteatoma or middle-ear carcinoma may also damage the facial nerve. In the absence of a careful examination of the tympanic membrane, such a case may be wrongly diagnosed and treated as Bell's palsy. All facial palsies should have an otological assessment.
Bilaeral facial palsy is an interesting rarity. It is the facial asymmetry of facial palsy that is conspicuous and makes the diagnosis obvious; a bilateral facial palsy may not be so readily diagnosed.
Fig. 2.100 Bell's palsy is the commonest cause of facial palsy and is a lower motor neuron lesion of the facial nerve, of unknown etiology, involving a loss of movement of facial muscles, usually total, of one side of the face. This includes the muscles of the forehead (with facial paralysis due to an upper motor neuron lesion, such as a stroke, these muscles continue to function due to cross innervation distal to the cortex).
Pain in or around the ear frequently precedes Bell's palsy, and a history of draught on the side of the face may be significant. Bell's palsy may be recurrent and associated with parotid swelling (Melkersson-Rosenthal's syndrome).
The etiology and management of Bell's palsy is controversial, although the cause is almost certainly viral. Edema of the facial nerve near the stylomastoid foramen has been demonstrated. Most Bell's palsies recover completely and spontaneously within 6 weeks. If seen in the early stages, however, antiviral treatment and prednisolone orally should be given. Providing there is no general medical contraindication to steroids, "a" suggested dose of prednisolone is: *20 mg q.d.s. five days: 20 mg t.d.s. one day: 20 mg b.d. one day: 20 mg o.d. one day: 10 mg o.d. one day. Physiotherapy maintains tone in the muscles during recovery and also has a place in the management of Bell's palsy. Bilateral facial palsy is very rare. These cases, however, require investigation to exclude underlying disease, e.g., Lyme disease, sarcoidosis.
Fig. 2.101a, b Tests of facial nerve involvement. The level of involvement of the facial nerve in facial palsy can be determined by:
2 Stapedial reflex (impedance audiome-try).
These tests are reliable in traumatic section of the facial nerve to detect the level of injury. In Bell's palsy, the tests are of little value.
Was this article helpful?
Have you recently experienced hearing loss? Most probably you need hearing aids, but don't know much about them. To learn everything you need to know about hearing aids, read the eBook, Hearing Aids Inside Out. The book comprises 113 pages of excellent content utterly free of technical jargon, written in simple language, and in a flowing style that can easily be read and understood by all.