Case of bilateral Bell’s palsy

Abstract

A man in his 70s presented with a 4-day history of bilateral frontal headache and heaviness of the face. He was unable to close either of his eyes, to wrinkle his forehead bilaterally and to raise either corner of his mouth. The patient was admitted with a diagnosis of bilateral facial palsy. From history, epidemiology, physical and laboratory findings, Bell’s palsy was considered more probable than viral infection, Guillain-Barré syndrome and sarcoidosis. Oral administration of prednisolone, valacyclovir and mecobalamin were initiated promptly, which improved his symptoms. In areas in which Lyme disease is not endemic, we believe that Bell’s palsy is the most probable cause of isolated bilateral facial palsy. Patients with bilateral facial paralysis under the suspicion of Bell’s palsy should be immediately started on steroid therapy.

Background

Facial nerve palsy usually develops unilaterally; however, simultaneous bilateral facial nerve palsy also can occur, while the incidence is less than 2% in patients with facial nerve palsy.¹ Unilateral and bilateral are not clinically inclusive, but may be better considered separately because the possible causes epidemiologically differ between unilateral and bilateral facial nerve palsy. While Bell’s palsy accounts for around 70% of cases of unilateral facial palsy,² Bell’s palsy comprises only around 30% in patients with bilateral facial nerve palsy.^{3 4} Furthermore, opposed to unilateral facial nerve palsy, broad differential diagnosis including infectious, neurological, neoplastic, infiltrative and metabolic diseases should be considered in patients with bilateral facial nerve palsy. Here, we report a case of simultaneous onset of bilateral facial nerve palsy, which was diagnosed of Bell’s palsy and showed good response to steroid treatment.

Case presentation

A man in his 70s with hypertension presented with a 4-day history of bilateral frontal headache and heaviness of the face. He noted a 1-day history of an inability to close either of his eyes and difficulty in chewing. He did not experience weakness or numbness in his limbs, double vision, facial sensory disturbance, altered taste, hearing problems, hyperacusis, dysphagia or dysarthria. He recalled no prior respiratory or gastrointestinal infections or any physical trauma. Moreover, he had not travelled recently, had sexual intercourse or been vaccinated. His only medication was amlodipine. He had no family history of neurological or autoimmune diseases. He was an occasional drinker and had smoked 20 cigarettes a day for 35 years but quitted 18 years ago.

Investigations

On examination, the patient’s vital signs were normal. There were no icterus or pallor conjunctiva. No abnormalities were detected on cardiac and pulmonary auscultation. Abdominal examination revealed no hepatosplenomegaly. There was no rash, clubbing, cyanosis or oedema. The patient’s visual field was intact, and no abnormal ocular movement or pupillary light reflex were observed. He was unable to close either of his eyes, and Bell’s phenomenon was observed (figure 1). The patient was unable to wrinkle his forehead bilaterally and to raise either corner of his mouth. No other neurological abnormalities were detected. His complete blood count, complete metabolic panel and glycated haemoglobin were normal. There was no evidence of inflammation. Chest X-ray revealed no cardiac enlargement, pleural effusion or bilateral hilar lymphadenopathy. Cerebrospinal fluid analysis revealed no increase in cells, a normal glucose concentration and a mildly elevated protein concentration (76 mg/dL; reference, 10–40 mg/dL). Brain MRI (without contrast) revealed no abnormalities (figure 2).

Figure 1.

Bell's phenomenon.

Figure 2.

Brain MRI (without contrast) showing no cerebral infarction, acoustic nerve tumour or cerebellar atrophy. (A) Horizontal diffusion-weighted image. (B) Horizontal T1-weighted image.

Differential diagnosis

The patient was admitted with a diagnosis of bilateral facial palsy, grade IV (House-Brackmann method). Lyme disease was thought to be less likely, as it is rare in Japan and the patient had not travelled to areas where it is endemic. Diabetes mellitus and stroke were ruled out according to the test results. Therefore, Bell’s palsy, viral infection, syphilis, Guillain-Barré syndrome, sarcoidosis and multiple sclerosis were considered. Accordingly, the following tests were performed (all were negative): serum antibodies for herpes simplex virus, cytomegalovirus and Epstein-Barr virus; rapid plasma reagin; the serum angiotensin-converting enzyme concentration; serum anti-GM1IgG and anti-GQ1bIgG antibodies; and oligoclonal bands and myelin basic protein of the cerebrospinal fluid.

Treatment

While we were awaiting the above results, as there were no prodromal symptoms of viral infection, no history of vaccination, and no aphasia, diplopia, bullae or gait disturbance, Bell’s palsy was considered more probable than viral infection, Guillain-Barré syndrome and sarcoidosis. Therefore, oral administration of prednisolone (60 mg/day), valacyclovir (3000 mg/day), and mecobalamin (3000 µg/day) was initiated on the day of admission.

Outcome and follow-up

On day 2, the patient was able to close both eyes. Valacyclovir was discontinued on day 9 and prednisolone was tapered. On day 13, his symptoms disappeared and he was discharged. Considering the test results and the positive response to steroids, the patient was finally diagnosed with Bell’s palsy.

Discussion

Facial palsy usually develops unilaterally; however, simultaneous bilateral facial palsy also occurs, although with an incidence of less than 2% in patients with facial palsy.¹ Unilateral and bilateral cases are not clinically inclusive and may be better considered separately, as their aetiologies may differ. While Bell’s palsy accounts for approximately 60%–75% of cases of unilateral facial palsy,² it accounts for only approximately 30% of cases of bilateral facial palsy.^{3 4} Furthermore, as opposed to the case in unilateral facial palsy, the differential diagnosis of bilateral facial palsy is broad and should include infectious, neurological, neoplastic, infiltrative, and metabolic diseases.

This case underscores the importance of the appropriate and timely treatment of patients with bilateral facial palsy. For a better outcome, clinicians should immediately initiate steroid therapy in patients who present with bilateral facial paralysis and are suspected to have Bell’s palsy. It is necessary for clinicians to collect data with the available resources to allow differentiation of Bell’s palsy from other possible causes of bilateral facial palsy, including Lyme disease, viral infection, Guillain-Barré syndrome, sarcoidosis, diabetes mellitus, multiple sclerosis and brain stem infarction. In addition, in deciding whether to initiate treatment based on a probable diagnosis, clinicians should balance the possible benefits and harm.

The epidemiology of bilateral facial palsy varies among regions. In Europe, the incidence is highest in central and eastern European countries.⁵ In Asia, infected ticks are widespread, from western Russia, through Mongolia and north-eastern China, to Japan⁵; however, Lyme disease appears to be uncommon in most of these areas. Lyme disease is highly endemic in the north-eastern and north-central United States.⁵ In a study in Texas, Lyme disease was the most common cause of bilateral facial palsy (36%)⁶; in a study in Boston; however, Bell’s palsy was the most common cause (35%).⁴ Therefore, in areas where Lyme disease is endemic, clinicians should consider it first. In other areas, Bell’s palsy may reasonably be considered first, and clinicians should prioritise the differentiation of Bell’s palsy from other aetiologies. The differentiation of Bell’s palsy and Guillain-Barré syndrome may be paramount. First, bilateral facial palsy can be the first and only symptom of Guillain-Barré syndrome, resulting in a poor prognosis (it occurs in up to 50% of fatal cases); it indicates a large degree of motor involvement and possible respiratory failure.^{3 7} Second, its first-line treatment differs from that of other diseases such as Bell’s palsy and sarcoidosis.

The patient’s response to steroids can be a useful marker for the discrimination of several possible diagnoses in patients with bilateral facial palsy. For example, the functional prognosis of the facial nerves in bilateral Bell’s palsy is thought to be comparable to that in unilateral cases.⁸ Although the response time to steroid treatment varies among cases, immediate recovery has been observed in patients with bilateral Bell’s palsy.⁹ Sarcoidosis also responds to steroids, with a typical response time of 2–4 weeks for improvement of the bilateral facial palsy.¹⁰ On the other hand, patients with Guillain-Barré syndrome normally do not rapidly respond to steroids without plasma exchange or intravenous immunoglobulin administration, while spontaneous remission occurs in 95% of patients within 4 weeks of onset.⁴ Hence, we believe the diagnosis of Bell’s palsy in this case was reasonable, as the patient rapidly responded to steroids, and there were no information of sarcoidosis, Guillain-Barré syndrome or other diseases suggesting these diagnoses. However, patients with certain viral infections (Epstein-Barr virus and varicella-zoster virus) can also respond to steroid treatment; these possibilities were excluded via laboratory testing. We believe that it is reasonable to initiate steroids in patients with bilateral facial palsy in areas where Lyme disease is rare, and in whom no other abnormal findings are observed, unless there are contraindications.

In conclusion, in areas where Lyme disease is not endemic, we believe that Bell’s palsy is the most probable cause of isolated bilateral facial palsy. Hence, clinicians should focus on the discrimination of Bell’s palsy and other diseases in deciding whether the patient is a suitable candidate for steroidal therapy. In future, more detailed epidemiological studies will be conducted, and this information will contribute to accurate differential diagnosis.

Learning points.

• Clinicians should consider Bell’s palsy as the primary cause of bilateral facial paralysis in areas where Lyme disease is not endemic.

• Also in the non-endemic areas, clinicians should differentiate Bell’s palsy from other aetiologies including Guillain-Barré syndrome, sarcoidosis, viral infection, diabetes mellitus, multiple sclerosis and brain stem infarction.

• Patients with bilateral facial paralysis under the suspicion of Bell’s palsy should be immediately started on steroid therapy.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).