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Five years ago, a young woman awoke with the inability to move the left side of her face and presented to her family physician. She was pregnant at that time. On examination, she had absent brow furrowing, weak eye closure, and dropping of her mouth angle (Figure 244-1). She was diagnosed with Bell palsy and was provided eye lubricants and guidance on keeping her left eye moist. Her physician discussed the available evidence about treatment with steroids. She chose not to take the steroids because of her pregnancy.
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Bell palsy is an acute paralysis of the facial nerve of unproven etiology resulting in loss of brow furrowing, weak eye closure, and dropped angle of mouth. Treatment is oral steroids as soon after the onset of symptoms as possible. Most patients have a full recovery within 6 months.
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Bell palsy is a diagnosis of exclusion. Although Bell palsy has been synonymous with idiopathic facial paralysis, peripheral facial nerve palsy is a clinical syndrome with many causes. In most cases of Bell palsy, herpes simplex or other suspected viral etiology is likely the causative agent. If some degree of facial nerve function fails to return within 4 months, a diagnosis of Bell palsy is questionable and a more extensive evaluation is warranted.1
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The syndrome is named after Sir Charles Bell, a 19th-century Scottish anatomist who described the facial nerve and its possible association to this condition.2
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In a Canadian study, incidence was 13.1 to 15.2 per 100,000 adults.3
In the United States, Bell palsy affects approximately 40,000 Americans annually.2
In a study of U.S. military members, the incidence was 42.77 per 100,000, with higher incidence in females, blacks, and Hispanics; arid climate and cold months were independent predictors of risk with adjusted relative risk ratios of 1.34 and 1.31, respectively.4
Women who develop Bell palsy in pregnancy have a 5-fold increased risk of preeclampsia or gestational hypertension.5
Seventy percent of cases of acute peripheral facial nerve palsy are idiopathic (Bell palsy); 30% have known etiologic factors such as trauma, diabetes mellitus, polyneuritis, tumors, or infections such as herpes zoster, leprosy (Figure 244-2), or Borrelia.6
Seven percent to 15% of patients with Bell palsy may experience recurrent attacks. ...