Myasthenia Gravis

1. Myasthenia Gravis By Millie Patchan SPT

2. Myasthenia Gravis (MG) • Chronic autoimmune neuromuscular disease • Immune system attacks muscle neurotransmitters (NTs) • Occur at any age, in any ethnic group, or gender • Most commonly occurs in women <40 y/o & men >50 y/o • Not inherited or contagious • Can be passed onto new born from a mother (12-20%) w/MG, but symptoms subside w/in a few months

3. MG • 20/100,000 people have been diagnosed in the US; believed to be under diagnosed • Affects voluntary muscles, most commonly affected muscles are those that control swallowing, facial expression, and eye • Occurrence can be sudden • 5-10% of those with MG have another autoimmune disease

4. Symptoms • Symptoms variable from person to person • Drooping eye • slurred speech • difficulty breathing • Weakness in arms or legs • Blurred or double vision • Change in facial expression • Unable to hold a steady gaze

5. Complications • MG poses greater risk if it affects muscles of inspiration and expiration • Symptoms are increased during periods of continuous activity • Symptoms decrease with rest • Up to 80% of muscle contraction is lostresulting in weakness

6. Mechanism Behind MG • Communication between the nerve and muscle are disrupted • Normally: • Nerve transmits Acetocholyine (Ach) in NMJ after brain sends a signal you want to move a voluntary muscle to a peripheral efferent • Ach moves through NMJ and binds to Ach receptorcausing an action potential which leads to contraction of voluntary muscle • With MG immune system creates antibodies which attack Ach receptors in NMJ • Action potential is not able to be produced, therefore voluntary muscle cannot contract

7. Current Theory • Not known how a person gets MG • Could contract MG from bone marrow transplant or being treated by interferon alpha (medication) • Thymus gland is the main culprit • In patient’s with MG the thymus gland is abnormally large • Contains clusters of immune cells (lymphoid hyperplasia) • Believe MG is triggered from illness or other event in the presence of genetic predisposition or abnormal thymus gland

8. Diagnosis • Can often be missed or misdiagnosed due to muscle weakness being primary symptom • Physical exam, medical history • Examine eye muscles for signs of weakness • Blood test to check for Ach receptor antibodies or anti-MUSKantibodies • Those with MG will have either of these present in the blood or none, but will typically have an elevated level of antibodies

9. Diagnosis • CT/MRI on thymus to detect thymoma • Nerve conduction test to detect muscle fatigue • In patient’s with MG fatigue occurs much quicker than normal • Single fiber EMG: measures electrical potential from a nerve to a muscle • Low measurement can be a sign of MG

10. Prevention • No way to prevent it • Symptoms do decrease with rest

11. Causes of Exacerbation of MG • Excessive Heat • Fatigue • Illness • Stress • Some medications

12. Treatment • Can be controlled with therapies and medication • Life style changes: • Avoiding stress • Avoiding excessive heat • Scheduling rest periods throughout the day • Medications that suppress the immune system • (prednisone, azathioprine, cyclosporin, mycophenulate, mofetil, tracrolimus) • Plasmaphoresis (decreased number of Ach antibodies) • Intravenous immunoglobin infusion (decreased number of Ach antibodies)

13. Treatment • Thymsectomy (removal of thymus gland) • Could cause complete remission or significant decrease in symptoms (only performed when thymoma present)

14. Prognosis • Remission is possible w/proper treatment and medication • Does not affect life expectancy • Women with MG can have children • Can lead normal lives • Concern if have myesthenia crisis= breathing muscles are too weak to breath, requiring immediate medical attention and respiratory assistance

15. Tolerance to Exercise • Exercise is not appropriate during MG exacerbations • A consistent exercise program is most beneficial to decrease effects of exacerbations • Exercise programs will vary with each individual case due to variability of symptoms

16. Exercise Considerations • Patients should exercise at their best time of the day • Exercise large proximal muscles for short periods of time until a moderate intensity is reached • Patient’s should not exceed moderate intensity exercise • Mild to moderate exercise intensities are best • Exercise at peak doses of pyridostigmine • Use “dollar per day rule”

17. How to Determine Exercise Intensity • HR should not rise greater than 30 bpm from resting • Patient’s should not become SOB during exercise • Symptoms should not become worse during exercise (watch for drooping of eyelids) • Patient’s should not be fatigued 2 hours after therapy • Patient’s should not have significant muscle soreness day(s) post exercise

18. Exercise Equipment to Utilize • Nustep • Elliptical with stationary arms • Recumbent bike • Stationary bike • Upper arm ergometer • AVOID treadmills

19. Areas of Focus for Exercise • Large proximal muscles • Posture muscles • Breathing exercises • Balance exercises • Gait training

20. Exercises • Breathing exercises: • Increase respiratory endurance • Pursed lip breathing • Abdominal breathing • Postural exercises: • Increase ability of lungs to expand, allowing more oxygen into the lungs • Scapular retractions • Chin tucks

21. Use of Modalities • Whole body cooling suggested by research for decreasing patient’s fatigue through • Cold showers/baths, cold suits, or cold packs

22. Education • Energy conservation techniques • Recommendations for equipment • Safety within the home and community • Individualized HEP

23. PT evaluation • Should include: • MMT • ROM • Assessment of mobility, transfers, gait, endurance, balance • Assess need for assistive device and patient’s safety awareness • Assess fall risk

24. PT treatment • As noted in above slides

25. Speech Therapy • Beneficial for communication deficits/disorders that can occur with MG • Dysphonia • Dysarthria • Dysphagia

26. ST evaluation • Assess: • Breathing for speaking • Eating/swallowing • Voice quality • Tolerance to activity

27. ST Treatment • Strengthening exercises for articulation • Compensatory strategies for articulation • Breathing exercises to improve voice/communication • Diet changes

28. OT evaluation • ROM • MMT • Assess mobility and transfers • ADLs and iADLs • Balance • Endurance • Assess fall risk, patient’s need for adaptive equipment, safety awareness

29. OT Treatment • Environment modifications (home, job, etc) • Energy conservation • Sleep hygiene • Task analysis & ergonomics • Breathing exercises • Balance exercises • Bed mobility

30. References • Conquer Myasthenia Gravis. (2017). What is MG? Known as Myasthenia Gravis. [online] Available at: http://www.myastheniagravis.org/about-mg/what-is-mg/ [Accessed 19 Oct. 2017]. • Naumes, J. and HaferMacko, C. (2017). Exercise and Myasthenia Gravis: A Review of the Literature to Promote Safety, Engagement and Functioning. • Howard, James F. Jr., MD, ed. “Myasthenia Gravis A Manual for the Health Care Provider.” Myasthenia Gravis Foundation of America (2008): 74-82. Myasthenia Gravis Foundation of America. Web. • Cass S. Myasthenia Gravis and Sports Participation. Head Neck and Spine. 2013; 12:18-21. • Kittiwatanapaisan W, Gauthier DK, Williams AM, Oh SJ. Fatigue in Myasthenia Gravis Patients. Journal of Neuroscience Nursing. 2003;35.2: 87-106. • Sheer BV, Valero-Burgos E, et al. Myasthenica Gravis and Endurance Exercise. Am J Phys Med Rehabilitation. 2012; 91.8: 725-727. • Weeks B. Myasthenia Gravis Helping Patients have Better Outcomes. The Nurse Practitioner. 2012; 37.9:31-36. • Merimier C, Schneider SM, et al. Preliminary Results: Effect of Whole Body Cooling in Patients with Myasthenia Gravis. Medicine & Science in Sports Medicine. 2006; 38.1: 13-20. • Conquer Myasthenia Gravis. (2017). YouTube Videos - Conquer Myasthenia Gravis. [online] Available at: http://www.myastheniagravis.org/we-can-help/youtube-videos/ [Accessed 19 Oct. 2017]. • YouTube. (2017). Myasthenia Gravis. [online] Available at: https://www.youtube.com/watch?v=BvZZgKgCQRM [Accessed 19 Oct. 2017].