A Primary Care Clinical Diagnosis: Bell Palsy

In this era of unprecedented technological innovations, it is rare to still be able to diagnose certain diseases solely on patient history and physical examination. One such disease that primary care practitioners frequently see is Bell palsy. After a diagnosis is made, there is level A evidence for effective treatment. Let’s look at a systematic clinical approach to making the diagnosis and then talk treatment.

Diagnosis

Q: Does the patient have a peripheral (and not a central) facial nerve palsy?¹ 

If it is Bell palsy, the forehead muscles are affected and the patient cannot wrinkle the forehead on the side with the peripheral seventh cranial nerve. If the forehead muscles are spared, you are dealing with a central lesion, not Bell palsy. The central lesion may be a stroke and has to be differentiated from Bell palsy immediately.

Q: Can the patient close her eyes tightly?¹ 

There are several physical exam findings that can aid in diagnosis. For example, the affected side in Bell palsy has incomplete closure of the eyelids. Also look for Bell phenomenon—when the examiner attempts to open the eyes, they deviate upward and laterally. Finally, observe the patient. When the patient blinks, the side with the seventh cranial nerve lesion lags behind the other eye.

Q: Is the smile symmetric?¹ 

Can the patient puff out her cheeks, purse her lips, and grimace the same on both sides of her face.¹ Inability to do so is consistent with Bell palsy.

Q: What else is important to do on your examination? 

Bell palsy is not the only etiology for peripheral seventh cranial nerve palsies.¹ The herpes family of viruses (both simplex and zoster) must also be considered. That means an otoscopic exam is necessary. The presence of vesicles may indicate an alternative cause like Ramsay Hunt syndrome—which can be thought of as zoster-shingles of the geniculate ganglion.¹ It also can cause unilateral peripheral seventh cranial nerve palsy. 

Lyme can also cause facial palsy (also peripheral) and can be seen in 50% to 63% of patients if they have Lyme meningitis.¹ Imaging is only recommended if your exam is atypical from Bell or other etiologies for peripheral nerve 7 palsies.¹ 

Treatment

Begin treatment as soon as possible. Corticosteroids should be initiated with the first 72 hours.¹ Prednisone can be administered as 50 mg orally for 5 days, followed by 10 mg less each successive day for 5 more days.¹ However, antivirals (acyclovir and valcyclovir) only add modest benefit (level C evidence) even when combined with the steroids.¹ This observation does not apply to Ramsay Hunt syndrome since it is clearly of viral etiology. Do not forget to protect the eye on the affected side from corneal ulceration.¹

Prognosis

Not everyone with Bell palsy gets better quickly—35% of those afflicted will still have signs at 6 months.¹ Furthermore, 7% to 12% of folks with Bell palsy will have a recurrence.¹ Rare individuals may require alternative, more invasive treatments (eg, botulinum toxin injections) for corneal ulceration, facial contractures, or spasms.¹ 

You do not need expensive imaging modalities to diagnose Bell palsy. In fact, such tests may only delay a diagnosis and intrude upon the importance of early diagnosis and treatment. The key here is to hone your exam skills and use them efficiently.

Gregory W. Rutecki, MD, is a physician at the National Consult Service at the Cleveland Clinic. He is also a member of the editorial board of Consultant. Dr Rutecki reports that he has no relevant financial relationships to disclose.

Reference:

1. Patel DK, Levin KH. Bell palsy: clinical examination and management. Clev Clin J Med. 2015;82(7):419-426.