How to Treat Bell’s Palsy

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altCorticosteroids, Antivirals, Both or Neither? 

The Bottom Line:
Most patients diagnosed with Bell’s Palsy will make a complete recovery but up to 30% will suffer long term pain and/or partial facial paralysis and the associated psychological problems. The most recent evidence indicates that prednisolone 25 mg twice daily improves these outcomes.

The Setup:
You are working a busy ED evening shift at your hospital, when a 54 year old healthy female presents to the ED with several hours of right-sided facial weakness. She’s fearful that this is a manifestation of stroke. The physical examination reveals no vesicles affecting either the palate or external auditory canal. The neurological examination is in keeping with a lower motor neuron lesion involving cranial nerve VII, i.e. involvement of the forehead muscles. The upper muscles of facial expression are spared in upper motor neuron disorders because of duplicate innervation. Specifically, the portion of the motor nucleus of CN VII that controls the upper facial muscles is innervated by both sides of the cerebral cortex. Therefore, a lesion to one side of the cortex will only affect the contralateral lower facial function because the upper facial muscles are also is innervated by the ipsilateral cerebral cortex. You confirm the diagnosis of Bell’s Palsy with the finding of Bell’s phenomenon: as the patient attempts to close the right (affected) eye, you see a brisk upward movement of the eyeball to the extent that the pupil becomes hidden under the eyelid. You reassure the patient that this is a common problem with the facial nerve and not a stroke. You also explain that given the clinical findings, a head CT is of very limited diagnostic value as it will almost certainly be normal.


The Treatment Choices:
-Discharge them with reassurance that this isn’t a stroke and to follow-up with their primary care physician.
-Send the patient to Dr. Somebody Else (ENT or neurology);
-Prescribe a corticosteroid and appropriate follow up;
-Prescribe an antiviral agent and appropriate follow up;
-Prescribe both a corticosteroid and an antiviral agent and appropriate follow up;

The Evidence:
Sullivan FM, Swan IR, Donnan PT, Morrison JM, Smith BH, McKinstry B, Davenport RJ, Vale LD, Clarkson JE, Hammersley V, Hayavi S, McAteer A, Stewart K, Daly F. Early treatment with prednisolone or acyclovir in Bell’s palsy. N Engl J Med. 2007 Oct 18;357(16):1598-607.

Confused about the best treatment option for these patients? Welcome to the club.


While corticosteroids and antiviral agents either alone or in combination are the most commonly prescribed therapies, recent systematic reviews revealed a lack of evidence to support the use of either or both therapies. To resolve this issue, the UK National Institute for Health Research commissioned an independent academic group. The result was a randomized controlled trial across 17 sites in Scotland enrolling more patients than all of the previous studies combined. Their subjects were adults (> 16 years old) with acute peripheral facial weakness (Bell’s palsy) within the previous 72 hours. The treatment interventions were acyclovir 200mg 5x/day or prednisolone 25mg twice daily or both, all for a 10-day course and were compared to placebo. The primary outcome for this study was the House–Brackmann grading system for facial-nerve function, a validated and objective measure of recovery from Bell’s palsy, at three and nine months.

At three months, 83.0% of patients in the prednisolone group vs. 63.6% in the non- prednisolone group fully recovered (P<0.001) while 71.2% in the acyclovir group vs. 75.7% who did not receive acyclovir (P = 0.50) fully recovered. At nine months, these proportions were 94.4% for the prednisolone group vs. 81.6% for the non-prednisolone group (P<0.001) and 85.4% for the acyclovir group and 90.8% for the non-acyclovir group (P = 0.10).

Does adding the two therapies improve the recovery rate?

Apparently not because for patients treated with both drugs, the complete recovery rates were 79.7% at 3 months (P<0.001) and 92.7% at 9 months (P<0.001). There were no serious adverse events in any group.
BEEM Bottom Line:
The strengths of this study over previous studies are in the high methodological quality and the certainty of the results which comes from the analysis of more patients than the systematic reviews. The dosing of prednisolone 25mg twice daily is not the standard dose used by most emergency physicians and is likely adopted from the results of previous trials. Regardless, the numbers needed to treat for the primary outcome at three months 5.16 (95% CI: 3.78 – 8.57) and nine months 7.82 (95% CI: 5.89 – 13.67) are very impressive. This trial demonstrates the effectiveness of an inexpensive and readily available medication (prednisolone) for this common condition compared to an expensive but apparently ineffective one.

Andrew Worster, MD, MSc
BEEM (Best Evidence in Emergency Medicine) Faculty
Associate Professor, Division of Emergency Medicine, McMaster University


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