Bell's palsy

• Bell's palsy is a facial nerve palsy that can have a dramatic impact on patients’ quality of life.
• Holistic management of Bell's palsy is essential to the individuals’ wellbeing.
• Treatment should be designed on a case-by-case basis depending on the severity of the symptoms.
• The use of corticosteroids and antivirals has been controversial.

Facial nerve paralysis can have a dramatic effect on patients’ quality of life, potentially leaving them permanently disfigured. They can occur as a result of neoplasia or congenital abnormality, or can be a consequence of infection, trauma, toxic exposures or iatrogenic causes.

Bell's palsy, also known as idiopathic facial paralysis (IFP), is thought to be the most common cause of acute unilateral facial paralysis. The exact aetiology of the disorder remains elusive, with some attributing it to viral, inflammatory or autoimmune causes, and others to ischaemia (Williamson and Whelan, 1996). The hallmark of the condition is a rapid (often overnight) onset of partial or complete facial paralysis. In rare cases (1%) it can occur bilaterally resulting in total facial paralysis (Gilden, 2004; Kim et al, 2008).

Although defined as a mononeuritis (involving only one nerve), Bell's palsy sufferers may present with a myriad of neurological symptoms that are unexplained by

Bell's palsy is thought to occur because of inflammation and/or oedema of the facial nerve (cranial nerve VII). Swelling causes the nerve to be compressed within the bony confines of the facial canal as it exits the skull. The resulting pressure and possible ischaemia (caused by a lack of circulation from the vasa nervorum) blocks the transmission of neural signals or, worse, damages the nerve (Seok et al, 2008). The cause of the inflammation is yet to be understood. However, in a few cases, bilateral facial palsy has been associated with acute HIV infection.

During Bell's palsy, inflammation of the facial nerve is thought to occur at or near the geniculate ganglion.

1. If damage occurs proximal to the ganglion then motor, parasympathetic and sensory fibers will be affected.
2. If inflammation occurs between the ganglion and the start of the chorda tympani then lacrimation is spared.
3. If the inflammation is at

The symptoms of Bell's palsy usually develop suddenly and evolve rapidly, typically reaching a peak within 3 days to a maximum of 1 week. This abrupt onset of symptoms can be alarming for patients, who may fear that they have had a stroke (Holland and Weiner, 2004; Tiemstra and Khatkhate, 2007).

Affected patients complain of weakness or complete paralysis of all the muscles on one side of the face (Figure 2). This presents as loss of facial creases on the affected side, loss of the nasolabial fold and forehead wrinkles, as well as an inability to elevate the forehead on the affected side (Tiemstra and Khatkhate, 2007).

Loss of innervation to the orbicu-laris oculi muscle results in failure of eye closure and sagging of the lower eyelid, often accompanied by Bell's phenomenon, in which the eyeball rolls upwards on attempted eye closure. The resulting corneal exposure, in addition to reduced

The diagnosis of Bell's palsy is usually reached by thorough history and physical examination. As no apparent cause will be found in most cases, no laboratory tests are immediately indicated or conducted. However, if the clinical findings are doubtful or if paralysis is prolonged and insidious, further investigations should be considered.

• Brain magnetic resonance imaging (MRI) and computer tomographic (CT) scanning are required to evaluate the patient for ischaemia, infectious and inflammatory diseases or mass lesions.
• If the patient's history suggests exposure to Lyme disease, serum antibody titres (immunoglob-ulin M and G) for Borrelia burgdorferi should be obtained.
• Fasting glucose or haemoglobin A1C levels may be obtained to determine whether the patient has undiagnosed diabetes.
• Cerebrospinal fluid examination is useful in assessing for inflammatory or neoplastic processes.
• Rising serum titres to herpes viruses may be obtained but are not a reliable diagnostic tool.
• Electroneurography (which should only be performed after

Treatment of Bell's palsy should begin early in order to attenuate the pathological processes that affect the facial nerve. Psychological support and regular follow-up are also paramount to a better recovery (Holland and Weiner, 2004).

A deficient understanding of the aetiology of Bell's palsy and conflicting data concerning medication efficacy have meant that an optimal strategy for treating the condition is yet to be established. However, even without any treatment Bell's palsy tends to have a good prognosis: 71% of patients achieve complete recovery and 84% achieve near normal function without pharmacotherapy (Grogan and Gronseth, 2001).