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| Acute Idiopathic Facial Palsy (Bell's Palsy) |
| Overview |
 | Acute peripheral paralysis of the face produced by a viral
immune-mediated disease. |
| Possible pathogenesis:
 | After a primary infection, herpes simplex virus became latent in the
cranial and spinal sensory ganglia. |
| Reactivation of the virus leads to replication of virus within the
ganglion cells. |
| Virus travels up and down the axons, induces an inflammatory response. |
| Results in segmental demyelination presented as nerve
paralysis. |
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| Incidence: between 15 - 40 / 100,000 population
per year |
| No evidence of racial predilection |
| Incidence of Bell's palsy increases with age. |
| Sexual predilection:
| Age 10 - 19 years, twice as common in women |
| Age 40, 1.5 times more common in men. |
| Pregnant women have 3.3 times more risk than nonpregnant women in the
same age group. |
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| Diabetic patients: 4.5 times more likely to develop Bell's palsy. |
| In 10% of the patients, a positive family history of Bell's palsy is
present. |
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| Clinical features |
| Sudden onset |
| Full extent of the paralysis is usually reached in 1 to 14 days. |
| Early phase: retroauricular pain, facial numbness, epiphora, parageusia,
decreased tearing, and hyperacusis. |
| Physical findings:
| Peripheral Facial paresis |
| Hypoesthesia or dysesthesia of cranial nerves V and IX |
| Motor paresis of cranial nerves IX and X |
| Papillitis of the tongue. |
|
| When severe retroauricular pain is present, Ramsay Hunt syndrome has to
be considered. |
|
| Differential diagnosis of VII weakness |
| Bells' palsy, usually unilateral, 10% bilateral |
| Differential of Unilateral Facial weakness
| Sarcoid |
| Lyme's disease |
| Neoplasm or mass |
| Otitis media |
| Trauma: skull fracture, facial injury |
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| Differential for bilateral VII palsy
| Melkersson-Rosenthal syndrome
 | Recurrent facial palsy with facial edema, Unilateral or bilateral |
| Lingua plicata (Scrotal tongue) |
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| Möbius syndrome: Facial paresis with ophthalmoplegia |
| Guillain-Barré Syndrome |
| Myasthenia gravis |
| Motor neuron disease |
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| Prognosis |
| Complete recovery in 60 to 80% |
| Prognostic factors:
| Age: younger patient has better prognosis. |
| Incomplete paralysis tends to recover completely. |
| If recovery begins between days 10 and 21, a satisfactory result is
obtained. |
| Presence of systemic diseases, such as diabetes, increases chance of
unsatisfactory recovery. |
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| Treatment |
| Acyclovir and prednisone produce better results than prednisone and
placebo. |
| Steroid:
| There is debate about the efficacy of steroids |
| Seems to have strong support in the literature for the use of
steroid. |
| Steroids relieve pain and reduce denervation. |
| Dosage: Prednisone is 1 mg/ kg of body weight daily for
6 days, tapering
to 0 during the next 4 days. |
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| Acyclovir (Zovirax):
| Reduces pain and degree of denervation. |
| Dosage: 400 mg five times per day for 10 days. |
| Not FDA approved for this indication. |
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| Eye Care: artificial tears five times per day and to tape the eye closed
during sleep. |
| Surgical Decompression: probably not beneficial. |
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| Further reading |
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