Case Report: Bell’s palsy: a neurological manifestation of COVID-19 infection

Introduction

Coronavirus (COVID-19) infection has affected millions of people worldwide. It’s an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). People with COVID-19 infection have a wide range of reported symptoms, ranging from a mild cough to acute respiratory syndrome (ARDS).¹ Patients with COVID-19 commonly face complications and potential causes of mortality, including conditions such as sepsis, acute kidney injury, ARDS, acute hypoxic encephalopathy, and acute cardiac injury.¹

A growing number of COVID-19 cases have been associated with facial nerve paralysis, often presenting as the initial symptom or occurring within the first week after the onset of viral symptoms or a positive COVID-19 test.²

The relationship between COVID-19 and neurological complications, including facial palsy, is complex and has been the subject of ongoing research. While some cases report facial nerve paralysis occurring within a week of viral symptom onset, there is variability in the reported timeframes.³

Additionally, individuals may experience other neurological complications such as loss of smell (anosmia), altered taste perception (dysgeusia), encephalopathy, Guillain-Barre syndrome, Miller-Fisher syndrome, and polyneuritis cranialis.⁴ In this case we’re reporting a case of Bell’s palsy following COVID-19 infection in a previously healthy 35-year-old-male. This case report follows the CARE guidelines.¹⁵

Case presentation

A 35-year-old South Asian male taxi driver with no past medical history presented to the Emergency Department of Hamad General Hospital complaining of a two day history of sudden right-sided facial weakness associated with fever, cough, and sore throat. Three days before admission the patient had gone to a primary health care center due to upper respiratory tract symptoms, and a diagnosis of COVID-19 was made.

Two days later, the patient suddenly developed weakness associated with numbness, drooling saliva while eating and difficulty closing the right eye. He had no other neurologic symptoms and denied ear pain, skin rash, or arthralgia. He had no recent history of travel, or a tick bite. The review of other systems was unremarkable.

At the Emergency Department, his temperature was 37°C, his peripheral pulse rate was 70 bpm, and his respiratory rate was 18 breaths per minute. His oxygen saturation was 98% on room air, blood pressure was 122/74 mmHg. Physical examination revealed the absence of right-sided forehead wrinkles compared to the left, drooping of the right eyelid, and prominent mouth deviation suggestive of right lower motor neuron facial nerve palsy. Careful examination of ears showed dry impacted wax in the right ear with no vesicles. Examination of the parotid gland was unremarkable. Sensation in both upper and lower extremities was intact. No weakness was noted in either the upper or lower limbs. Kernig’s and Brudzinski’s signs were negative. Examination of other systems was unremarkable.

The patient’s complete blood count and basic metabolic panel were within normal ranges. His COVID-19 rapid antigen test was positive. The chest X-ray was unremarkable. A diagnosis of Bell’s palsy potentially related to COVID-19 infection was made, and the patient was discharged and prescribed the following medications:

He was also referred to a physical therapy clinic. On his four-week follow-up visit, the patient showed no significant improvement. On his 10-week follow up clinic appointment, the patient symptoms showed a significant improvement.

Discussion

Besides the usual and well-known respiratory symptoms, SARS-CoV-2 can affect the peripheral and central nervous systems. Neurological symptoms can be the first manifestation of COVID-19 infection or concurrent respiratory symptoms. A retrospective review reported neurological symptoms in 36.5% of patients.⁵

Two different mechanisms could explain the neuropathogenesis of SARS-CoV-2. The first mechanism is due to endothelial damage and the subsequent passing of the virus from the systemic circulation to the cerebral circulation. The alternative mechanism is thought to be due to the direct entering of the virus through the cribriform wall and olfactory bulb, where the olfactory nerve terminates.⁶ Using the olfactory pathways, the virus can harm the central nervous system (CNS), which may propagate from neuron to neuron by axonal transport.⁷

When glial cells get infected with the virus, the body enters a pro-inflammatory state and releases cytokines. The prolonged exposure to cytokines may lead to nerve damage.⁸

Moreover, various types of neurological manifestations of COVID-19 infection have been reported.⁹

An observational study conducted in Spain documented cases where COVID-19 was associated with cranial nerve manifestations. In one of these cases, polyneuritis cranialis developed on the third day, while in the other case, Miller Fisher syndrome occurred on the fifth day.¹⁰ A previous study also described a case of an isolated facial paralysis presented after six days in a patient with COVID-19 infection.² Our patient experienced a lower motor neuron facial paralysis on the third day of his ongoing COVID-19 infection.

Bell’s palsy is a lower motor neuron impairment of the facial cranial nerve, manifesting acutely as a unilateral facial paralysis.¹¹ Although the reason for many cases is unidentifiable, the most common cause of peripheral facial palsy is attributed to infections, mainly Herpes Simplex Virus-1 (HSV-1), Varicella Zoster Virus (VZV), and Lyme disease.³ Our patient denied any recent travel, trauma, insect bite, skin rash, joint pain, itchiness, or tingling sensation in the body. Physical examination was unremarkable, with no skin rash; the outer ear canal was clear, and no signs of meningitis. Causes such as autoimmune and vasculitis were excluded as the patient did not have any systemic findings. Human Immunodeficiency Virus (HIV) infection was also excluded as it is a part of the infectious screening for all people getting their residencies in the country. The patient had a fever, sore throat, and generalized body pain, and his COVID-19 rapid antigen test came positive. Therefore, no other etiologies than COVID-19 infection could be attributed to palsy.

COVID-19 infection is known to present mainly as respiratory symptoms ranging from mild to severe, such as ARDS and fever.¹² In addition, neurological manifestations, including Guillain-Barre syndrome, anosmia/ageusia, encephalopathy, and myelitis, are also encountered.³ Bell’s palsy is one of the manifestations of COVID-19. Poor prognosis is predicted in patients >60 years of age with systemic problems such as diabetes mellitus, severe pain in the ear, and decreased tear production. Bell’s palsy generally has a good prognosis and recovery rate of 90%.¹³ Regarding the treatment, the most used one in facial paralysis is corticosteroids, with high effectiveness rates.¹² Prednisolone’s effect on the facial nerve is by reducing its edema.¹⁴ In our case, the patient had no risk factors for poor prognosis; he was prescribed prednisolone (20 mg) for 10 days and referred to a physiotherapy clinic. His four-week follow-up visit showed no significant change in his condition. However, on his 10-week follow-up clinic visit his weakness improved significantly.

Conclusions

This case report raises the possibility that Bell’s palsy and COVID-19 infection are related. However, to prove the causal association, more cases with epidemiological data are required. For a deeper knowledge of COVID-19 infection, it is crucial to investigate its neurologic symptoms. Therefore, additional research is needed to fully understand the prognostic importance of cranial neuropathies in COVID-19 disease and their natural history and choose the most effective therapy approach.

Consent

Written informed consent for publication of their clinical details was obtained from the patient.