Bell’s Palsy-2

            Bell’s palsy is an abrupt onset of unilateral facial paralysis.  This condition is also called idiopathic facial paralysis because the cause is unknown (Zalvan, Huo, and Selesnick, 1999).  The paralysis is caused by damage to the VII cranial, or facial, nerve (Slavkin, 1999).  The facial nerve splits into three major branches that affect facial expression, tears, salivation, and taste sensation (Slavkin, 1999). The symptoms are both socially and physically difficult to cope with.  The cause is controversial and the diagnosis is critical.  Fortunately, the prognosis for Bell’s palsy is promising.  Several treatment options are being explored to speed the recovery time.   

            Without the innervation of the facial nerve, the skin tissue of the face will appear droopy, and the individual will be unable to make facial expressions (Bell’s palsy).  The most significant symptom, emotionally, is the inability to smile, because the zygomaticus major muscle is innervated by the zygomatic branch of VII (Slavkin, 1999).  Other symptoms include decreased tearing with an inability to close the eye, otalgia, hyperacusis, and retroauricular pain (Zalvan et al., 1999).  Dysgeusia (impairment of gustatory sense) may also be present because the autonomic fibers that control the salivary glands and the sensory fibers for the posterior two thirds of the tongue are both carried by the facial nerve (Slavkin, 1999).  Also noted on the tongue may be papillitis of the fungiform papillae due to the chorda tympani division of the facial nerve (Zalvan et al., 1999).    

            The cause of Bell’s palsy remains unknown, but many studies are suggesting possibilities.  While it is known that the paralysis is due to the inflammation of cranial nerve VII, the cause of the inflammation itself is controversial.  Cranial nerves are vulnerable to injury where they pass through foramina in bone (Slavkin, 1999).  The nerve can become pinched when inflammation occurs in these bony openings.  Of the suggested etiologies, several studies have mentioned viral infection, vascular entrapment, autoimmune reactions, and infectious diseases as the source of Bell’s palsy (Zalvan et al., 1999). 

The most evidentiary cause is the Herpes simplex virus or HSV (Zalvan et al., 1999).  Studies have found the virus to be present in the nasopharynx of infected individuals, as well as an increase in HSV serum antibodies (Zalvan et al., 1999).  Muscle biopsies and endoneurial fluid have also contained the virus when taken from a Bell’s palsy patient (Zalvan et al., 1999).  One theory suggests that HSV remains latent in neural ganglion and becomes reactivated by factors such as stress or immunosuppression (Zalvan et al., 1999).  The term herpetic facial paralysis may some day replace Bell’s palsy (Slavkin, 1999). 

            In order to diagnose Bell’s palsy, all other possibilities must be ruled out.  Bell’s palsy is not the only kind of facial paralysis (Zalvan et al., 1999).  Other causes may include traumatic, neoplastic, infectious, congenital, or metabolic sources (Zalvan et al., 1999).  One must consider the possibility of parotid gland neoplasms or an otologic cause (Zalvan et al., 1999).  Thus, the patient’s medical history must be examined.  According to two physical therapists, patients who are referred to physical therapy treatment for Bell’s palsy have later discovered the paralysis to be caused by a parotid tumor (Brach & VanSwearingen, 1999).  This reinforces the importance of early detection, such as when a dental hygienist is performing an extraoral examination.  Then the patient can be appropriately referred for other diagnostic services. 

The minimum diagnostic criteria for Bell’s palsy include:

·         Paralysis of all muscle groups on one side of the face

·         Sudden onset of less than 48 hours

·         Absence of signs of CNS disease

·         Absence of signs of ear or cerebellopontine angle syndrome

(Zalvan et al., 1999).     

            The prognosis for Bell’s palsy is promising, with about 80% of patients recovering without treatment (Slavkin, 1999).  The likelihood of recovery depends on whether the paralysis was complete upon presentation (Zalvan et al., 1999).  Abrupt onset, early return of function, and partial paralysis seem to indicate a good prognosis (Zalvan et al., 1999).  Generally, recovery should begin at three weeks following onset (Zalvan et al., 1999).  If, however, recovery begins around two to four months, then chances of permanent damage increases (Zalvan et al., 1999). 

            Although most people will recover without any intervention, it has become standard to treat patients regardless (Zalvan et al., 1999).  A variety of regimens have been researched in clinical trials.  Some to include are corticosteroids, NSAID’s, and analgesics (Slavkin, 1999).  Those that demonstrated improvement were the corticosteroid prednisone and the antiviral drug acyclovir (Zalvan et al., 1999).  The most controversial treatment is surgical decompression of cranial nerve VII, which, despite its long term success, is too risky a procedure (Zalvan et al., 1999).  Facial massage has also been suggested as a palliative option (Bell’s palsy).  Often times the eye will become dry, since the patient is unable to blink.  Consequently, hourly eye drops of saline solution should be applied, along with an ophthalmic ointment at night (Zalvan et al., 1999). 

            Bell’s palsy affects a patient’s physical, emotional, esthetic, functional, and social needs (Zalvan et al., 1999).  It can be socially embarrassing to have a droopy face, and can affect an individual’s self-esteem.  Activities such as eating and communicating can be difficult for the patient, and may be taken for granted by the caregiver.  Therefore, in order to provide the best care possible, a dental hygienist must keep these factors in mind when treating a patient with Bell’s palsy (Zalvan et al., 1999).              

References 

Bell’s palsy (April 2002).  Retrieved October 18, 2002 from

http://www.mayoclinic.com/findinformation/diseasesandconditions/index.cfm

Brach, J.S., & VanSwearingen, J.M. (1999).  Not all facial paralysis is Bell’s

            palsy: A case report.  Archives of physical medicine and rehabilitation,

            80 (7), 857-859.

Slavkin, H.C. (1999).  The significance of a human smile: Observations on Bell’s

            palsy.  Journal of the American Dental Association, 130 (2), 269-272.

Zalvan, C.H., Huo, J., and Selesnick, S.H. (1999).  Bell’s palsy: An update on

            causes, recognition, therapy [Electronic version].  Consultant, 39 (1), 39.