Peripheral facial paralysis is often idiopathic (known as Bell's palsy) but it may also be caused by the herpes virus, borreliosis, otitis, trauma or, in rare cases, by a tumour.
The diagnosis of Bell's palsy is made by excluding other causes.
An adult with a characteristic Bell's palsy can be examined and treated in primary care. If peripheral facial paralysis is prolonged or the clinical picture is atypical, the patient should be referred to an ENT specialist for investigations and treatment. Paediatric patients should always be referred for emergency consultation of an ENT specialist or a paediatrician.
Symptoms and workup
The function of muscles of facial expression is either impaired or absent, usually on one side, only. On the affected side, raising of the eyebrow and wrinkling of the forehead are impaired, the eye cannot be properly closed, and raising the angle of the mouth (smiling, grimacing) and pursing of the lips to whistle are either impaired or impossible.
The degree of paralysis may vary in different parts of the face, and it may become worse during the first couple of days. It may be difficult to distinguish Bell's palsy from central paralysis at first if there is some paralysis in the mouth area, already, but the eyes can still be closed. If so, ask the patient to blink his/her eyes more rapidly; if the eye on the affected side lags behind, the eye area is involved in the paralysis.
In small children, in particular, in whom facial function must be defined from the child's spontaneous facial expressions or while the child is crying, isolated weakness of the inferior branch of the facial nerve is often misinterpreted. As the function of the facial nerve is impaired, the lower lip turns towards the teeth and the angle of the mouth on the unaffected side is pulled downward when the child cries while the angle on the affected side does not move. The angle of the mouth on the unaffected side can therefore be misinterpreted as drooping as a sign of paralysis.
Facial paralysis is often associated with taste disturbances, decreased secretion of tear fluid, pain around the ear and headache on the affected side, and hyperacusis (sounds being perceived as too loud).
Examine the ears to exclude acute or chronic inflammation and other diseases, and perform tuning fork tests in order to test hearing.
Palpate the parotid glands to exclude tumours.
Look for blisters signifying a herpes infection (see Shingles).
If the patient has a history of cancer, which could have recurred or metastasized to the head area, or if the ear on the side affected by the paralysis has been operated on, be very careful before diagnosing Bell's palsy.
Central facial paralysis (dysfunctional lower part of the face but functional forehead and eye areas) always requires neurological examination.
If the cause of the facial paralysis can be established, treatment should be provided according to the cause.
Paralysis causes both physical strain (dysfunctional eye affecting screen work, for example, dysfunctional mouth affecting eating, drinking, etc.) and mental strain (visible to anyone, disfiguring effect). The patient needs support and in the initial phase possibly sick leave.
Cooperation with an ENT specialist (botulin injections, for example), ophthalmologist or plastic surgeon (eyelid weights, eyelid surgery, dynamic and static reconstructive surgery, etc.) may be needed to deal with any sequelae.
It is unclear whether antiviral medication (such as 1 g valaciclovir 3 times daily for 7 days) combined with a glucocorticoid promotes recovery (antiviral medication alone does not help) http://www.dynamed.com/condition/bell-palsy#ANTIVIRALS. In Finland, routine use of antiviral medication is not recommended; in other countries, the practice varies.
There is no good research available on pharmacotherapy of children with Bell's palsy. The practice varies in various countries.
The prognosis of Bell's palsy is good but in one third of the patients some degree of residual disturbance in the functions of the face will remain, mostly mild.
Causes the so called Ramsay Hunt syndrome (facial paralysis + shingles).
In addition to facial paralysis, the symptoms and signs include vesicles on the earlobe and in the outer auditory canal, on the tympanic membrane, oral mucosa, the face or shoulders.
The vesicles may precede facial paralysis (by as much as several weeks), occur concomitantly with it or appear only after the onset of paralysis.
May be associated with vertigo and impaired hearing.
If the facial paralysis does not represent typical Bell's palsy, or if it is prolonged or recurs rapidly on the same side, MRI of the head may be required, using thinner slices along the course of the facial nerve.
References
Engström M, Berg T, Stjernquist-Desatnik A et al. Prednisolone and valaciclovir in Bell's palsy: a randomised, double-blind, placebo-controlled, multicentre trial. Lancet Neurol 2008;7(11):993-1000. [PubMed]
Sullivan FM, Swan IR, Donnan PT et al. A randomised controlled trial of the use of aciclovir and/or prednisolone for the early treatment of Bell's palsy: the BELLS study. Health Technol Assess 2009;13(47):iii-iv, ix-xi 1-130. [PubMed]
Peitersen E. Bell's palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Otolaryngol Suppl 2002;(549):4-30. [PubMed]