Facial nerve paralysis: report of two cases of Bell's palsy.

The cases of an ll-year-old white male and an 8-year-old black male with facial paralysis are presented. Included are descriptions of diagnosis, clinical course, treatment, prognosis, and recommendations for future cases. Facial nerve paralysis is an important cause of morbidity in children. Its presentation can be frightening for both the child and parents. The most common cause of facial nerve paralysis in children is Bell’s palsy2 Bell’s palsy is the accepted term to describe unilateral, peripheral facial nerve paralysis which is idiopathic with acute onset. 2 Sometimes facial nerve paralysis is a sign of an underlying disease process. Because the facial nerve courses through intracranial, intratemporal, and extracranial regions, determination of the etiology of facial nerve paralysis is complicated (Olsen 1984). May et al. (1981) evaluated 170 children over a 17-yearperiod (1963-80) and found that Bell’s palsy accounted for 42% of the facial nerve paralyses. The remaining causes in children were trauma (21%), otitis media (13%), syndromes (13%), congenital (8%), and (2%) (May et al. 1981). Depending on the cause, prognosis of facial nerve paralysis may be spontaneous regression or rapid morbidity and fatality. It should not be assumed that a child presenting with facial nerve paralysis has Bell’s palsy because more serious disorders can cause similar signs and symptoms (May et al. 1981). The purpose of this case report is to present 2 children with facial nerve paralysis. The diagnosis and course of each were very different and these cases underscore the important role of the pediatric dentist in recognition and referral of such cases. 1 Adour 1982; May et al. 1981; Olsen 1984. ~Olsen 1984; Blattner 1969; McGovern a d Estevez 1983; Peitersen 1982. Review of Facial Nerve Anatomy The facial (7th cranial) nerve has parasympathetic, motor, and sensory nuclei in the pons, a part of the brain stem located in the posterior cranial fossa. The fibers from the motor nucleus pass below the floor of the 4th ventricle and continue around the nucleus of the abducens (6th cranial) nerve to combine with parasympathetic and sensory fibers to form a common nerve trunk. The nerve trunk exits the brain and continues its lateral course through the facial canal. Where the canal makes an acute bend toward the middle ear cavity, the geniculate ganglion is located. At the level of the geniculate ganglion, the greater superficial petrosal nerve arises and supplies parasympathetic fibers to the lacrimal gland and mucous membrane of the nose and mouth (Fig 1). 3 Distal to the geniculate ganglion, the facial nerve gives rise to 2 branches. The first contains the motor nerve to the stapedius muscle, which serves to dampen the oscillations of the ear ossicles. The second is the chorda tympani nerve, which contains sensory fibers for taste from the anterior 2,4 of the tongue. The chorda tympani nerve also joins with the lingual nerve and provides parasympathetic innervation to the submandibular and sublingual glands. The facial nerve exits the temporal bone through the stylomastoid foramen and subdivides into its terminal branches, which supply the motor innervation to the muscles of facial expression. Central Versus Peripheral Lesions of the Facial Nerve The facial nerve primarily innervates the muscles of facial expression. There are 2 types of paralysis affecting the motor function of the facial nerve and 30lsen 1984; Alford et al. 1973; Carpenter 1978; Montgomery 1981. 58 FACIAL NERVE PARALYSIS: Keels et al.