2.7 Cranial Nerve Disorders

2-37. BELL'S PALSY

Bell's Palsy is a cranial nerve disorder characterized by facial paralysis. Peripheral involvement of the 7th cranial nerve (facial nerve) produces weakness or paralysis of the facial muscles. The cause of this condition is unknown, but the majority of patient's have experienced a viral upper respiratory infection 1 to 3 weeks prior to the onset of symptoms. Complications associated with Bell's palsy include facial weakness, facial spasm with contracture, corneal ulceration, and blindness.

The signs and symptoms Bell's Palsy include distortion of face, numbness of face and tongue, and speech difficulty secondary to facial paralysis. There are  also the seemingly opposing signs: An overflow of tears down the cheek from keratitis caused by drying of cornea and lack of blink reflex, and decreased tear production that may predispose to infection.

The primary objectives of nursing care are to maintain muscle tone of the face and to prevent or at least minimize denervation.

It is also important to protect the involved eye. If the blink reflex is absent, the eye is vulnerable to dust and foreign particles. To counteract this symptom, instill artificial tears (methylcellulose) to protect the cornea, increase environmental humidity, and instruct patient to close affected eye frequently using accessory facial muscles.

The patient should wear a protective patch at night, keeping in mind, however, that the patch may eventually abrade cornea as paralyzed eyelids are difficult to keep closed. It is also helpful to wear protective glasses to further protect eye and decrease normal evaporation of moisture from eye.

You may be instructed by the physician to administer steroid therapy. (This often reduces inflammation and edema and restore normal blood circulation to the nerve.)

Providing for pain relief with analgesics and local application of heat may be in order as well as facial massage may be prescribed to help maintain muscle tone.

Surgical intervention may be necessary for decompression of facial nerve and correction of eyelid deformities.

2-38. TRIGEMINAL NEURALGIA

Trigeminal neuralgia, also known as Tic Douloureux, is a disorder of the 5th cranial nerve (trigeminal nerve). It is characterized by sudden paroxysms of burning pain along one or more of the branches of the trigeminal nerve. The pain alternates with periods of complete comfort.

The signs and symptoms include sudden, severe pain appearing without warning (along one or more branches of trigeminal nerve), numerous individual flashes of pain, ending abruptly and usually on one side of the face only, and attacks provoked by pressure on a "trigger point" (the terminals of the affected branches of the trigeminal nerve). Such triggers include shaving, talking, yawning, chewing gum, and experiencing cold wind.

Care considerations include the avoidance of environmental triggers such as sudden exposure to cold--iced drinks, cold wind, and swimming in cold water, for example. Drug therapy may take the form of Tegretol or Dilantin which relieve and prevent pain in some patients, but require monitoring serum blood levels of in long-term use.

Surgical procedures my be recommended to sever the affected nerve provide optimum pain relief with minimum impairment.