Bell’s Palsy - Cranial Nerve Disorders

BELL’S PALSY

Bell’s palsy (facial paralysis) is due to unilateral inflammation of the seventh cranial nerve, which results in weakness or paralysis of the facial muscles on the affected side (Fig. 64-8). The cause is unknown, although possible causes may include vascular ischemia, viral disease (herpes simplex, herpes zoster), autoimmune disease, or a combination of all of these factors. The incidence is 13 to 34 cases per 100,000; it increases with age and among pregnant women in the third trimester (Campbell & Brundage, 2002; Shmorgun, Chan & Ray, 2002).

Bell’s palsy is considered by some to represent a type of pres-sure paralysis. The inflamed, edematous nerve becomes com-pressed to the point of damage, or its nutrient vessel is occluded, producing ischemic necrosis of the nerve. There is distortion of the face from paralysis of the facial muscles; increased lacrimation (tearing); and painful sensations in the face, behind the ear, and in the eye. The patient may experience speech difficulties and may be unable to eat on the affected side because of weakness or paralysis of the facial muscles.

Management

The objectives of treatment are to maintain the muscle tone of the face and to prevent or minimize denervation. The patient should be reassured that no stroke has occurred and that sponta-neous recovery occurs within 3 to 5 weeks in most patients.

Corticosteroid therapy (prednisone) may be prescribed to re-duce inflammation and edema; this reduces vascular compression and permits restoration of blood circulation to the nerve. Early administration of corticosteroid therapy appears to diminish the severity of the disease, relieve the pain, and prevent or minimize denervation.

Facial pain is controlled with analgesic agents. Heat may be applied to the involved side of the face to promote comfort and blood flow through the muscles.

Electrical stimulation may be applied to the face to prevent muscle atrophy. Although most patients recover with conserva-tive treatment, surgical exploration of the facial nerve may be in-dicated in patients who are suspected of having a tumor or for surgical decompression of the facial nerve and for surgical treat-ment of a paralyzed face.

PROMOTING HOME AND COMMUNITY-BASED CARE

Teaching Patients Self-Care.

While the paralysis lasts, the in-volved eye must be protected. Frequently, the eye does not close completely and the blink reflex is diminished, so the eye is vul-nerable to dust and foreign particles. Corneal irritation and ul-ceration may occur if the eye is unprotected. Distortion of the lower lid alters the proper drainage of tears. To prevent injury, the eye should be covered with a protective shield at night. The eye patch may abrade the cornea, however, because there is some difficulty in keeping the partially paralyzed eyelids closed. The application of eye ointment at bedtime causes the eyelids to ad-here to one another and remain closed during sleep. The patient can be taught to close the paralyzed eyelid manually before going to sleep. Wrap-around sunglasses or goggles may be worn to de-crease normal evaporation from the eye.

Continuing Care.

When the sensitivity of the nerve to touch de-creases and the patient can tolerate touching the face, the nurse can suggest massaging the face several times daily, using a gentle upward motion, to maintain muscle tone. Facial exercises, such as wrinkling the forehead, blowing out the cheeks, and whistling, may be performed with the aid of a mirror in an effort to prevent muscle atrophy. Exposure of the face to cold and drafts is avoided.