Myasthenia gravis,

Myasthenia gravis

1. MYASTHENIA GRAVIS

2. INTRODUCTION The name myasthenia gravis , which is Latin and Greek in origin ,means “ grave,or serious ,muscle weakness “. Autoimmune disease affecting the neuromuscular junction . *Its not a brain disorder – brain functions normally. Characterized by fluctuating muscle weakness and fatigability .

3. DEFINITION Myasthenia gravis is an autoimmune disorder affecting the myoneural junction, is characterized by varying degree of weakness of the voluntary muscles.

4. Anatomy & Physiology

5. Anatomy The anatomy of NMJ consists of following parts: Pre-synaptic membrane : it contains pre- junctional acetylcholine receptors and active zone Synaptic cleft : lies between the muscle endplate and nerve terminal which are held in tight by basal lamina

6. Conti… Post-synaptic membrane : at the post –synaptic membrane area overlying the nerve terminal is called muscle endplate. The membrane here is thrown into primary and secondary cleft Contractile apparatus : it is formed by thin actin , thick myosin filaments tropomyosin & troponin.The shortening of this apparatus causes the contraction of the muscle

7. Physiology Neuromuscular junction is specialized on the nerve side & on the muscle side to transmit & receive chemical messages Each motor neurons runs without interuption from the ventral horn of spinal cord to NMJ as a large myelinated axon As it approaches muscle it branches to contract many muscle cells together into functional group known as Motor unit

8. INCIDENCE MG affects 14 per 100,000 people in the United States . Can affect any age group . Women – peak incidence 20s to 30s. Men- peak incidence 50s to 60s.

9. CAUSES Idiopathic. Autoantibodies that destroys acetylcholine receptors. Thymus tumors found in 15% of patients .

10. RISK FACTORS It include: Female gender and age under 40years. Male gender and age under 60years. Other autoimmune disorders .

11. PATHOPHYSIOLOGY DUE TO AUTOIMMUNE RESPONSE DEVELOPMENT OF AUTOANTIBODIES ANTIBODIES ATTACK ACETYLCHOLINE [ACT] RECEPTORS AT THE MOTOR END PLATE

12. CONTI… ACT AGAINST THE NICOTINIC ACETYLCHOLINE RECEPTOR IMPAIR THE ABILITY OF ACETYLCHOLINE To BIND THE RECEPTORS RESULTING IN VOLUNTARY MUSCLE WEAKNESS THAT ESCALATES WITH CONTINUED ACTIVITY

13. CLINICAL MANIFESTATIONS Affects any voluntary muscle groups Eye , face, throat , neck, limb muscles The hallmark of myasthenia gravis is fatigability Dysphagia Ptosis Diplopia Nasal sounding speech Worsening muscle weakness

14. ASSESSMENT & DIAGNOSTIC EVALUATION ASSESSMENT History Physical examination Diagnostic Evaluation Edrophonium test [ Tensilon ] Blood analysis Ice pack test Repetitive nerve stimulation Pulmonary function tests Single –fiber electromyography (EMG) Imaging scans

15. Physical Examination Muscle strength and tone Coordination Sense of touch Impairment of eye movements

16. Edrophonium test Injection of the chemical edrophonium ( Tensilon ) may result in a sudden, althugh temporary , improvement in muscle strength –an indication that patients may have myasthenia gravis

17. Blood Analysis A blood test may reveal the presence of abnormal antibodies that disrupt the receptor sites where nerve impulses signal muscles to move

18. Ice Pack Test Cooling may improve neuromuscular transmission. In a patient with myasthenia gravis who has ptosis , placing ice over an eyelid will lead to cooling of the lid , which leads to improvement of the ptosis

19. Repetitive Nerve Stimulation Repetitive nerve stimulation , which repeatedly stimulates a person’s nervers with small pulses of electricity to tire specific muscles. Muscle fibers do not respond as well to repeated electrical stimulation .

20. Single –Fiber Electromyography (EMG) It considered the most sensitive test for myasthenia gravis , detects impaired n er ve –to-muscle transmission . Imaging Scans CT Or MRI : Its shows thymus enlargement

21. MANAGEMENT

22. Medical Management Pharmacological management Non pharmacological management

23. Pharmacological Management Immunosuppressive Therapy -Prednisone -Azathioprine Acetylcholinesterase Inhibitors -First line therapy -Neostigmine bromide ( Pyridostigmine ) - Edrophonium chloride ( Tensilon ) Plasmapheresis Immunoglobulin Therapy

24. Non- Pharmacological Management Eat small meals and snacks 5-6 times a day Avoid using low fat or diet products when possible Avoid eating lemons or tonic water Eat warm rather than hot food Runny or puree diet when swallowing is difficult Alternative sips of liquid to avoid food from sticking AVOID eating chewy or dry crumbly foods

25. Surgical Management Thymectomy : (surgical removal of the thymus gland) can produce antigen –specific immunosuppression and result in clinical improvement .

26. Dietary Management Reduce protein intake to 10 percent of total calories ; replace animal protein as much as possible with plant protein Eliminate milk and milk products (substitute other calcium sources ) Eat more fruits and vegetables (make sure that they are organically grown) Take ginger

27. Nursing Management Maintain patient airway Assess swallowing to prevent aspirations Keep appropriate equipment available at the bedside Provide energy conservation measures Consult with speech and language therapist if weakening facial muscles impact communication Monitor I/O, serum albumin levels, and daily weights Administer Medications as per order

28. Priority Needs Need to maintain normal breathing pattern Need to improve physical mobility Need to improve verbal communication Need to reduce muscle weakness

29. Nursing Diagnosis Ineffective breathing pattern related to intercoastal muscle weakness Impaired physical mobility related to voluntary muscle weakness Impaired verbal communication related to weakness of the larynx , lips , mouth , pharynx and jaw Risk for aspiration related to weakness of the bulbar muscles Disturbed sensory perception related to ptosis , and decreased eye movements

30. Complications Myasthenic crisis Thymus tumors Thyroid problems Lupus Rheumatoid arthritis

31. Health Education Teach patient / family about disease condition Teach patient about their medications, uses, dosages , etc Advice patient to improve physical movement Teach the patient to do speech therapy Instruct the patient continue the follow up

32. Conclusion Myasthenia gravis is an autoimmune disease affecting the neuromuscular junction . It causes muscle weakness . Myasthenia gravis may affect individuals of any age and we have largest experience in India for treatment of Myasthenia gravis