Facial paralysis, or the inability to control facial muscles, may result from a number of conditions. The most common cause is Bell's palsy. Other possible causes include viral infections, fracture, tumors, or stroke. Children may be born with congenital paralysis of the face or it may be acquired.
Bell's palsy results in unilateral, or one-sided, facial paralysis. It may be caused by a viral infection, possibly herpes simplex 1, which causes swelling of the facial nerve. The paralysis generally goes away in about two weeks, although some people take as much as three months to fully heal. A small number of Bell's palsy sufferers have permanent symptoms.
Viral infections are known to cause facial paralysis. If the facial nerve near the ear becomes infected with the herpes zoster virus, Ramsay-Hunt syndrome may result. The symptoms of Ramsay Hunt syndrome include the shingles rash, hearing loss, vertigo, and facial paralysis. Treatment with antiviral medications and corticosteroids helps to avoid permanent damage.
Otitis media, or an infection of the middle ear, may also cause facial paralysis if the infection spreads to the facial nerve. An infected nerve can become inflamed, swell, and become compressed in the ear canal. The first line of treatment is antibiotics. If this does not cure the problem, a myringotomy, or incision into the tympanic membrane, may be necessary.
Fractures of the temporal bone may also be responsible for paralysis of the face. A horizontal transverse fracture causes paralysis in 40-50% of cases. Symptoms may include vertigo, blood behind the tympanic membrane, and hearing loss. A vertical longitudinal fracture of the temporal bone causes paralysis in 20% of cases. The patient with this type of fracture may present with symptoms such as blood coming out of the ear canal, a torn tympanic membrane, hearing loss, or fracture of the auditory canal. Treatment may include surgery or benzodiazapines.
A tumor may cause paralysis that gets worse over time and may twitch. It is sometimes quite difficult for the surgeon to remove the tumor without damaging the nerve. If the tumor is benign, care can be taken to preserve as much of the nerve as possible. Malignant tumors may require resection of part of the facial nerve and some non-malignant surrounding tissues; this will likely result in more severe facial paralysis.
A stroke that damages the upper motor neurons of the facial nerve may result in central facial palsy. It usually causes paralysis of the lower half of one side of the face. Physical or occupational therapy may be recommended to help strengthen the muscles.
Children may sometimes be born with paralysis of the face. It may also be later in childhood. The paralysis may affect one or both sides. Unilateral paralysis might be caused by Goldenhar syndrome. This is a type of hemifacial microsomia in which one side of the face has developed more completely than the other.
Moebius syndrome is a congenital condition that results in bilateral facial paralysis. This condition may be caused by incomplete development of the blood vessels that feed the muscles and nerves in the face. Children with this condition cannot show emotion or move their eyes side to side.
Acquired facial paralysis may occur in babies delivered with forceps. This nerve injury usually resolves in several months, but sometimes the paralysis is permanent. Surgical treatment may be suggested to correct the paralysis. Head injuries, muscle damage, or severing of the facial nerve are other reasons a child may develop acquired paralysis of the face.