Neuromuscular Disorders Part 3 Presented by F. Briggs MS, APRN-C January 13, 2010 January Intersession

Myasthenia Gravis A neuromuscular disorder in which there is a disturbance in the transmission of impulses from nerve to muscle cells at the neuromuscular junction, causing extreme muscle weakness Most commonly occurs bet, ages of 10 and 65. Peaks age of onset in women is years, and over 40 for men

Myasthenia Con’t Ninety percent of cases show eyelid muscles or extraocular muscle involvement. Facial mobility and expression can be impaired, and there may be difficulty w/chewing and swallowing. Speech can also be affected and when prolonged-voice fades.

Etiology Autoimmune disorder whereby antibodies destroy acetylcholine receptor sites on the post- synaptic membrane of the neuromuscular junction, resulting in a decreased number of ACh receptor sites at neuromuscular junction. This prevents ACh molecules from attaching and stimulating muscle contractions. Anti-ACh receptors are detectable in 85-90% of patients with generalized MG and in 50-60% of patient’s with ocular MG (most common in men)

Signs and Symptoms Diplopia, dysphagia Extreme muscle weakness, increased with activity and reduced with rest Ptosis, mask like facial expression Difficulty with feeding and chewing Weak voice, hoarseness *There is no sensory loss, reflexes are normal, and muscle atrophy is rare

Diagnosis of Myasthenia Gravis Tensilon test- IV injection of Tensilon provides spontaneous relief of symptoms (last 5-10minutes)-increased muscle contractility Electromyelography (EMG)- amplitude of evoked potential decreases with repeated tests Presence of Anti-acetylcholine receptor antibodies in the serum is present in % of cases

Crisis Myasthenic- Exacerbation of myasthenia following precipitating factors of failure to take drug as prescribed or drug dose too low. Cholinergic- Overdose of anticholinesterase drugs resulting in increased Ach at the receptor sites, remission is spontaneous or after thymectomy

Medical Management Drug therapy- anticholinesterase drugs- ambenonium (Mytelase), neostigmine (Prostigmine), and Pyridostigmine (Mestinon) These drugs act by blocking the action of cholinesterase and increases the levels of acetylcholine at the neuromuscular junction SE’s- excessive salivation and sweating, N/V/D, fasciculations (twitching) Corticosteroids- Prednisone- used if other drugs are not effective Suppress the autoimmune response

Surgery Thymectomy- surgical removal of the thymus gland-thought to be involved in the production of acetylcholine receptor antibodies. Indicated in all patients w/Thymoma, generalized MG between ages of puberty and 65, and for patients with purely ocular MG. *May cause remission in some clients especially if performed early in the disease Plasma exchange (Plasmaphoresis)- removes circulating acethylcholine receptor antibodies Use in clients who don’t respond to other therapies

Nursing Considerations Give medication exactly on time Give with milk and crackers to decrease SE’s Monitor effectiveness of drugs by assessing muscle strength and vital capacity before and after medication Avoid using morphine and strong sedatives, quinine, TCA’s Lithium carbonate, Benzo’s, aminoglycosides -gentamycin, neomycin, streptomycin- skeletal muscle blocking effect

Nsg. Considerations con’t Promote optimal nutrition- mealtimes should coincide w/ effects of drugs- give medications at least 30min before meal Check gag reflex and ability to swallow Provide soft mechanical diet If patient has difficulty eating/swallowing-keep emergency equipment nearby Monitor respiratory status frequently, plans to take advantage of energy peaks and provide frequent rest periods

Bell’s Palsy Is a form of temporary facial paralysis resulting from damage or trauma to one of the two facial nerves. The facial nerve also called the 7 th cranial nerve-is a paired nerve that travels through a narrow, bony canal (called the fallopian canal) in the skull, beneath the ear, to the muscles of the side of the face.

Bell’s Palsy con’t Each facial nerve directs the muscles on one side of the face, including those that control eye blinking and closing, and facial expressions such as smiling and frowning. In addition, it carries nerve impulses to the lacrimal (tear glands), the saliva glands, and to the muscles of the middle ear bone-called the stapes. It also transmits taste sensations from the tongue

What Causes Bell’s Palsy? Bell’s palsy occurs when the nerve that controls the facial muscles is swollen, inflamed, or compressed, resulting in facial weakness or paralysis. However, what exactly causes this damage, is unknown. There has been a viral link- Viral meningitis or the common cold, HSV1,2, HHV, CMV, Adenovirus, Hep. A,B, and C, Rubella, and Influenza virus

Who Get’s Bell’s Palsy? Bell’s palsy afflicts approximately 40,000 Americans each year. It affects men and women equally and can occur at any age, but is less common in children less than 15years old and in adults over age 60. Peak incidence is between the age of 15-45y/o. Also, increased incidence in people of Japanese descent. Disproportionately affects people with diabetes, women who are pregnant, and people with URI such as cold or Flu.

Symptoms of Bell’s Palsy Symptoms of bell’s palsy vary from person to person and range in severity from mild weakness to total paralysis. More importantly, symptoms occur suddenly and peak within 48hours. May include twitching, weakness or paralysis on one or both sides of the face Drooping of the eyelid and corner of the mouth

Symptoms Con’t Drooling, loss of taste, impaired speech Dryness of the eye or mouth Headache, ringing in the ears, increased sensitivity to normal sounds (Hyperacusis) Impairment in taste and excessive tearing of the eye (Epiphora) Dizziness Difficulty eating or drinking

Differential Diagnosis Stroke Tumors Other Infections- such as Meningitis Trauma Other neurological diseases such as Multiple Sclerosis **The physical exam and symptoms are the most important part of making a diagnosis of Bell’s Palsy

Treatment There is no standard treatment, some controversy over the use of steroids, but if used, recommended to start early. Recommended dosage is 1mg/kg/d PO for 7days. Use of Acyclovir or Valacyclovir (antiviral has been used)- normal adult dose 4,000mg/24hr PO for 7-10days. In children >2y/o- 1,000mg PO QID for 10 days. If Lyme’s disease suspected- use Abx like Doxycycline Use of analgesics (Aspirin, Tylenol, or Motrin)

Other Treatments Another important factor is eye protection- use of artificial tears, lubricants, and eye protection Physical therapy to stimulate the facial nerve, including massage to prevent permanent contractures Moist heat to reduce pain on the affected side Vit. B12, B6, and Zinc which help nerve growth

Treatments con’t Based on severity of symptoms-some people require surgery for nerve decompression Remember % recover with no permanent damage, 10-15%- experience incomplete recovery of nerve function, but no cosmetic effects (i.e., twisted mouth) 5-10% experience permanent neurological sequelae that are cosmetically and clinically apparent

Prognosis Bell’s Palsy usually goes away by itself without treatment. The extent of nerve damage determines the extent of recovery. Most people begin to recover within 2-3weeks, with 70-85% of the people showing complete recovery in 2-3months. There is a 10% recurrence rate. Those who are at highest risk of not getting better are often older and those who have a slower recovery from symptoms. Complete recovery is expected within 3- 6months

Guillain’ Barre Syndrome Ghee-yan-Bah-ray syndrome also called acute inflammatory demyelinating polyradiculoneuropathy and Landry’s ascending paralysis, is a life threatening inflammatory disorder of the peripheral nervous system- affects the peripheral nerves (i.e., those outside the brain and spinal cord). GBS is the most common cause of rapidly acquired paralysis in the United States today, affecting 1-3 people in every 100,000

Etiology of GBS The disorder came to public attention briefly when it struck a number of people who received the 1976 Swine Flu vaccine. The true cause of GBS is not known and there is no effective treatment. Approx. 50% of the cases occur shortly after a microbial (viral or bacterial) infection such as a sore throat, or diarrhea have cleared up. Some theorize an autoimmune mechanism, in which the patient’s defense system of antibodies and WBC’s are triggered into damaging the nerve covering or insulation (i.e., myelin sheath) leading to weakness and abnormal sensation.

Etiology Con’t According to Kumar, Abbas, and Fausto (2005), Infections with campylobacter jejuni, cytomegalovirus, Epstein barr-Virus, and Mycoplasma Pneumoniae have been shown to have a significant epidemiological association with GBS. Segmental demyelination affecting peripheral nerves is the primary lesion, but damage to axons is also characteristic, particularly when the disease is severe.

GBS Signs and Symptoms A rapid onset of ascending weakness, frequently associated with abnormal sensations that affect both sides of the body similarly-is a common presenting symptom It typically begins w/weakness and/or abnormal sensations of the legs and arms (from distal to proximal). It can also affect muscles of the chest, face, and eyes. Although many cases are mild, some patients are virtually paralyzed. Breathing may require the use of a ventilator. Loss of reflexes, such as knee jerk, are often found.

Diagnosis/Treatment of Guillain Barre-Syndrome Basically made on the presenting symptoms, but to confirm a diagnosis, a Lumbar Puncture is done and should show elevated fluid protein and an Electromyography (electrical test of the nerve and muscle) may be done. Initial focus is to maintain airway and monitor other body functions Plasma exchange ( a blood cleansing procedure) and high dose intravenous immune globulins (which help to neutralize the antibodies by attaching to them) are often helpful to shorten the course of GBS.