Bell palsy: Clinical examination and management
ABSTRACTBell palsy is a common neurologic disorder characterized by acute facial mononeuropathy of unclear cause presenting with unilateral facial weakness. Careful examination and a detailed history are important in making an accurate diagnosis. Early recognition is essential, as treatment with corticosteroids within 72 hours of onset has been shown to hasten recovery. Fortunately, most patients recover spontaneously within 3 weeks, even if untreated.
KEY POINTS
- Bell palsy is an acute disorder of the facial nerve causing unilateral facial weakness, pain, abnormal taste, and reduced tearing.
- Although herpes simplex virus reactivation is suspected in the pathogenesis, the exact cause is unknown.
- An additional workup is warranted for abnormalities beyond isolated facial nerve palsy.
- Guidelines recommend starting corticosteroids for patients who present within 3 days of symptom onset. There is no compelling evidence to support antiviral therapy, physical therapy, acupuncture, or surgical decompression.
TREATMENT
The treatment of Bell palsy focuses on maximizing recovery and minimizing associated complications.
Protect the eyes
Patients who cannot completely close their eyes should be given instructions on ocular protective care to prevent exposure keratopathy. Frequent application of lubricant eyedrops with artificial tears during the day or ophthalmic ointment at bedtime is recommended. The physician should also recommend protective eyewear such as sunglasses during the day. Eye patching or taping at night may be useful but could be harmful if applied too loosely or too tightly. Patients with vision loss or eye irritation should be referred to an ophthalmologist.19
Corticosteroids are recommended in the first 72 hours
In two randomized clinical trials (conducted by Sullivan et al20 in 511 patients and Engström et al21 in 829 patients), prednisolone was found to be beneficial if started within 72 hours of symptom onset.
In a double-blind, randomized, placebo-controlled study of prednisone in 58 patients, those who received the drug recovered faster, although long-term outcomes in these patients were not significantly different than those in the control group.22 The American Academy of Neurology23 rated this study as class II, ie, not meeting all of its criteria for the highest level of evidence, class I. Nevertheless, although prednisone lacks class I evidence, its use is recommended because it is a precursor to its active metabolite, prednisolone, which has been studied extensively.
The current guidelines of the American Academy of Neurology, updated in 2012, state, “For patients with new-onset Bell palsy, steroids are highly likely to be effective and should be offered to increase the probability of recovery of facial nerve function”23 (level A evidence, ie, established as effective). They also concluded that adverse effects of corticosteroids were generally minor and temporary.
Similarly, the guidelines of the American Academy of Otolaryngology–Head and Neck Surgery, published in 2013, recommend oral corticosteroids within 72 hours of onset of symptoms of Bell palsy for patients age 16 and older.19 The recommendation is for a 10-day course of corticosteroids with at least 5 days at a high dose (prednisolone 50 mg orally daily for 10 days, or prednisone 60 mg orally daily for 5 days, followed by a 5-day taper). The benefit of corticosteroids after 72 hours is unclear (Table 3).19
Even though the guidelines recommend corticosteroids, the decision to use them in diabetic patients and pregnant women should be individualized. Discretion is advised, as not all patients with Bell palsy need to be treated. Most recover spontaneously, especially those with mild symptoms.
Antiviral therapy may offer modest benefit
Antiviral therapy has not been shown to be beneficial in Bell palsy, and current guidelines do not recommend oral antiviral therapy alone.19 However, an antiviral combined with a corticosteroid may offer modest benefit if started within 72 hours of symptom onset (level C evidence, ie, possibly effective).23 Patients starting antiviral therapy should understand that its benefit has not been established.
Surgical decompression remains controversial
A Cochrane systematic review in 2011 found insufficient evidence regarding the safety and efficacy of surgical intervention in Bell palsy.24 Surgery should be considered only for patients with complete paralysis with a greater than 90% reduction in motor amplitude on a nerve conduction study compared with the unaffected side, and absent volitional activity on needle examination.19,25
Acupuncture: No recommendation
Currently, there is no recommendation for acupuncture in the treatment of Bell palsy.19 A recent randomized clinical trial suggests benefit from acupuncture combined with corticosteroids,26 but high-quality studies to support its use are lacking.26
Physical therapy: Insufficient evidence
There is insufficient evidence to show that physical therapy has benefit—or harm—in Bell palsy. However, some low-quality studies indicated that facial exercises and mime therapy may improve function in patients with moderate paralysis.27
Follow-up
Patients should be instructed to call at 2 weeks to report progress of symptoms and to be reevaluated within or at 1 month, with close attention to facial weakness and eye irritation. Further evaluation is needed if there has been no improvement, if symptoms have worsened, or if new symptoms have appeared.
The psychosocial impact of Bell palsy cannot be discounted, as the disfigurement can have negative implications for self-esteem and social relationships. Appropriate referral to an ophthalmologist, neurologist, otolaryngologist, social worker, or a plastic surgeon may be necessary.
COMPLICATIONS AND PROGNOSIS
Most patients with Bell palsy recover completely, but up to 30% have residual symptoms at 6 months.14,20 Furthermore, although Bell palsy usually has a monophasic course, 7% to 12% of patients have a recurrence.3,15
Long-term complications can include residual facial weakness, facial synkinesis, facial contracture, and facial spasm.14,28 Incomplete eye closure may benefit from surgery (tarsorrhaphy or gold-weight implantation) to prevent corneal ulceration. Facial synkinesis is due to aberrant nerve regeneration and occurs in 15% to 20% of patients after recovery from Bell palsy.29 Patients may describe tearing while chewing (“crocodile tears”), involuntary movement of the corners of the mouth with blinking, or ipsilateral eye-closing when the jaw opens (“jaw-winking”). Facial contracture, facial synkinesis, and facial spasm can be treated with botulinum toxin injection.30
