The diagnosis of Bell palsy must be made on the basis of a thorough history and physical examination, as well as the use of diagnostic testing when necessary. Bell palsy is a diagnosis of exclusion. Clinical features of the disorder that may help to distinguish it from other causes of facial paralysis include the sudden onset of unilateral facial paralysis and the absence of signs and symptoms of central nervous system, ear, and cerebellopontine angle disease.
Symptoms of Bell palsy include:
Acute onset of unilateral upper and lower facial paralysis (over a 48-hour period)
Posterior auricular pain
An otologic examination includes pneumatic otoscopy and tuning fork examination. An otologic cause should be considered if the history or physical examination demonstrates evidence of acute or chronic otitis media, including a tympanic membrane perforation, otorrhea, cholesteatoma, or granulation tissue, or if a history of ear surgery is noted. Concurrent rash or vesicles along the ear canal, pinna, and mouth should raise the suspicion for Ramsay Hunt syndrome (herpes zoster oticus). The external auditory canal must be inspected for vesicles, erythema, infection, or trauma. The patient may have decreased sensation to pinprick in the posterior auricular area. Tympanic membranes should be normal; the presence of inflammation, vesicles, or other signs of infection raises the possibility of complicated otitis media.
The paralysis must include the forehead and lower aspect of the face. The patient may report the inability to close the eye or smile on the affected side. He or she also may report increased salivation on the side of the paralysis. Two thirds of patients complain about tear flow. This results from the reduced function of the orbicularis oculi in transporting the tears. Fewer tears arrive at the lacrimal sac and overflow occurs. The production of tears is not accelerated.
If a patient has gradual onset of facial paralysis, weakness of the contralateral side, or a history of trauma or infection, other causes of facial paralysis must be strongly considered. Progression of the paresis is possible, but it usually does not progress beyond 7-10 days. A progression beyond this point suggests a different diagnosis. Patients who have bilateral facial palsy must be evaluated for Guillain-Barré syndrome, Lyme disease, and meningitis.
Facial spasm, a very rare complication of Bell palsy, occurs as tonic contraction of one side of the face. Spasms are more likely to occur during times of stress or fatigue and may be present during sleep. This condition may occur secondary to compression of the root of the seventh nerve by an aberrant blood vessel, tumor, or demyelination of the nerve root. Facial spasm occurs most commonly in patients in the fifth and sixth decades of life. Sometimes the etiology is not found. The presence of progressive facial hemispasm with other cranial nerve findings indicates the possibility of a brainstem lesion.
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Cite this: Helmi L. Lutsep. Fast Five Quiz: Bell Palsy and Other Facial Paralysis - Medscape - Feb 27, 2020.