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MG ppt lectur and its cause and treatment
- 1. Myasthenia Gravis Shair Muhammad Hazara PhD Public Health (fellow), MSPH, MSBE, BSN Email add: hazara_27@Hotmail.com
- 2. LAY OUT Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 3. “It is a fluctuating weakness of certain voluntary muscles, particularly those innervated by motor nuclei of the brainstem, i.e. ocular, masticatory, facial, deglutitional, and lingual”. DEFINITION Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 4. Ø Can occur at any age. Ø In women:20-40 yrs. Ø In men:40-60 yrs. Ø Familial occurrence: Rare. Ø Spontaneous remission: 20%. Ø 90% no specific cause. Ø Genetic predisposing factor: HLA association. Ø Thymic tumor: 10%. EPIDEMIOLOGY Definition Epidemiology Pathophysiology Clinical Presentation Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 6. PATHOPHYSIOLOGY Ø Autoimmune response mediated by specific anti-AChR antibodies. Ø Sero-negative patients may have antibodies directed against other components of the NMJ e.g. MuSK. Ø Pathogenic antibodies are IgG and are T cell dependent, Sensitized T-helper cells. Ø Autoimmune response, the thymus appears to play a role. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 7. PATHOPHYSIOLOGY Ø Three pathogenic mechanisms: 1. AChR antibodies bind to acetylcholine binding site and block the receptor 2. AChR antibodies cross-link receptors leading to their internalization and breakdown 3. AChR antibodies bind complement leading to destruction of the muscle endplate (most common mechanism) Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 9. CLINICAL FEATURES Ø Fluctuating weakness of voluntary muscles (fatigability). Ø Worsen after exertion and improve with rest. Ø No abnormality of cognition, sensory function, or autonomic function. Ø Initial symptoms involve the ocular muscles in 60%. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 10. CLINICAL FEATURES Ocular manifestations: Ø Ptosis: uni- or bilateral is very common may occur while patients reading, or during long period of driving. Ø Diplopia: Extraocular muscle weakness may also be asymmetrically. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 11. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation CLINICAL FEATURES Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References Pictures taken with consent
- 12. Bulbar involvements: Ø Difficulty in chewing, speaking, or swallowing: initial symptoms in 17% of patients Ø Fatigability and weakness during mastication, Ø Unable to keep jaw closed after chewing. Ø Slurred and nasal speech. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation CLINICAL FEATURES Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 13. CLINICAL FEATURES Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation Weakness: Limb muscles: Ø Initial symptoms in fewer than 10%. Ø Upper extremities weakness is more common than lower extremities, asymmetrical. Involve proximal muscles than distal. Ø Involve neck muscles: neck flexion weaker than neck extension. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 14. CLINICAL FEATURES Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References Respiratory insufficiency: Ø The initial presentation is rare, Occurring precipitously in a patient with recent worsening of symptoms.
- 15. PRECIPITATING EVENTS Ø Systemic illness. Ø Viral upper respiratory tract infection. Ø Receiving general anesthesia. Ø Receiving neuromuscular blocking agents. Ø Pregnancy, menstrual cycle. Ø Extreme heat. Ø Stress. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 16. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References PRECIPITATING EVENTS Medications Inducing MG: Ø Antibiotics (Aminoglycosides, ciprofloxacin, ampicillin, erythromycin). Ø B-blocker (propranolol). Ø Lithium. Ø Magnesium. Ø Procainamide
- 17. CLASSIFICATION Osserman Classification: Ø Grade I: involve focal disease (restricted to ocular muscle). Ø Grade II: generalized disease: IIa: mild . IIb: moderate. Ø Grade III: severe generalized disease . Ø Grade IV: a crisis with life threatening impairment of respiration. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 18. CLASSIFICATION Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation MG Foundation of America Clinical Classification: Ø Grade I: Any ocular muscle weakness. Ø Grade II: Mild weakness affecting other than ocular muscles. IIa: limb and/or axial weakness; less oropharyngeaL involvement IIb: oropharyngeal and/or respiratory weakness. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 19. CLASSIFICATION Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References Ø Grade III: Moderate weakness affecting other than ocular muscles ( a,b). Ø Grade IV: Severe weakness affecting other than ocular muscles ( a,b). Ø Grade V: Defined by tracheal intubation.
- 20. DIAGNOSIS Ø Clinical manifestations: chronic intermittent muscle weakness; fatigability. Ø Provocative tests: 1-Physiologic: Look up for several minutes. Counting aloud to 100. Repetitively testing the proximal muscles. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 21. DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation Three different serial pictures demonstrate fatigue of eyelid muscles as patient keeps looking up. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References 1
- 22. DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation 2-Tensilon test: Ø Using edrophonium chloride: short acting Acetylcholinesterase inhibitor, 10 mg used. Ø A small test dose (2 mg) IV; after 1 min if no improvement and side effect, the remainder given slowly. Ø The effect of edrophonium starts in 30 sec and lasts fewer than 10 min. Cardiac monitoring. Atropine available: 0.6 mg IV. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 23. DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation 3-Neostigmine test: Ø Longer acting. Ø 1.5 mg IM or 0.5 mg IV. Ø Action begins in 15-30 mins and lasts up to 3 hours. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 24. DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation Electrophysiological tests: 1-Repetitive Nerve Stimulation Test: Ø 3 Hz is used for 60 sec. Ø Greater than 15% decrement of the amplitude of compound muscle action potential is considered positive. Ø The yield of the test increases if proximal nerves are stimulated. Ø May be abnormal in ALS, peripheral neuropathy. 2-Single Fiber Electromyography: Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 25. DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation Immunological tests: 1-Antibody to acetylcholine receptor: Ø Present in almost all patients with thymoma. Ø Absent in ocular type. Ø Absent in 20% of generalized MG. 2-Sero-negative MG: Ø 70% of SNMG patients have antibody to the muscle-specific receptor Tyrosine Kinase (MuSK). Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 26. Ice test: DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References Ø Muscles in MG function better at lower temperature. Ø Decreased Acetylcholinesterase activity Ø Increased depolarizing effect of acetylcholine at motor endplates. Ø Applying ice pack on the eyelid during closing for 2 mins. Ø Positive: lid fissure increases by 2 mm or more from baseline.
- 27. DIAGNOSIS Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References Before ice test After ice test
- 28. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References DIAGNOSIS RADIOLOGIC INVESTIGATIONS: X-ray chest. Contrast enhanced CT scan chest.
- 29. Ø Myasthenia Gravis Ø Intra Cranial Lesion Ø Progressive External Ophthalmoplegia Ø Hyperthyroidism Ø Brainstem gliomas Ø Lambert-Eaton Myasthenic Syndrome Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References DIFFERENTIALS
- 30. TREATMENT Ø The goal is to achieve remission. Ø Symptoms free and taking no medication. Ø By increased neuromuscular transmission. Ø Reduce autoimmunity. Ø Others: having a normal quality of life even if some signs remaining and cholinesterase inhibitors taking. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 31. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT THERAPEUTIC OVERVIEW: 1. Symptomatic treatments (anticholinesterase agents) 2. Chronic immuno-modulating treatments (corticosteroids and other immunosuppressive drugs). 3. Rapid immuno-modulating treatments (plasma exchange and intravenous immune globulin). 4. Surgical treatment (thymectomy). Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 32. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 33. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT 1-Acetylcholinesterase inhibitors ØPyridostigmine bromide is used . Ø Starting with 30 mg every 4 to 6 hours; titrated depending on clinical symptoms and patient tolerability. Ø60 mg Pyridostigmine = 15 mg Neostigmine. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 34. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT SIDE EFFECTS: ØCholinergic crisis ØAbdominal cramps and diarrhoea. ØIncreased bronchial secretions and bradycardia. ØIncreased fasciculations and muscle cramps. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 35. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT 2-Immunosuppressive therapy Steroids: Ø Start on low dose and gradually titrate dose up. Ø Remain on dose for 2 months. Ø Switch to alternate-day therapy. Ø Once, the condition stable, taper downward by 5 mg every month. Ø Azathioprine and cyclosporine are also used. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 36. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT Side effects: ØWeight gain. ØEasy bruising and skin fragility. ØCataract. ØHypertension. ØOsteoporosis. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 37. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT 3-IV Ig therapy: ØDose: 2 g/kg over 2-5 days. ØClinical improvement in 1-2 weeks and lasts weeks to months. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 38. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT IV Ig: : Side effect profile: ØAllergic response: low grade fever, chills, myalgia. ØDiaphoresis, fluid overload, HT. Ø Nausea, vomiting, rash, neutropenia. Ø Headache, aseptic meningitis Ø Hyperviscosity: stroke, MI, ATN (most serious with compromised renal glomerular filtration; DM). Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 39. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation TREATMENT 4-Plasmapheresis: ØDouble filtration plasma exchange and immuno-adsorption plasmapheresis. ØTo remove the circulating immune complexes and AchR-Ab. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 40. Complications: ØComplications (catheters): pneumothorax , bleeding, sepsis. ØHypotension. ØHypercoagulation, hypoalbuminemia. ØHypocalcemia, pulmonary embolism. ØArrhythmias (frequent exchanges). ØLow platelets, anemia. TREATMENT Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References
- 41. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References TREATMENT 5-Surgical intervention: ØThymectomy. ØPerformed in any antibody positive patient under 45 yrs with generalized MG.. Mechanisms: ú Eliminate a source of continued antigenic stimulation. ú Subside immune response. ú Correct a disturbance of immune regulation.
- 42. Management: ØStop every medication. ØAssisted ventilation if respiratory support required. ØTensilon test to estimate ChE-Inhs requirement. ØIf not improved by medications, IV Ig or plasmapheresis can be used. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References TREATMENT Myasthenic crisis:
- 43. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References TREATMENT First trimester and acute post partum period. Pyridostigmine: first line therapy. Second stage of labor affected. Appropriate steps taken in case of maternal fatigue. All infants of myasthenic mothers observed for first 48-72 hours. MG In Pregnancy:
- 44. Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References REHABILITATION Strategies emphasize: Ø Patient education. Ø S/S of underdose and overdose of medicines. Ø Instruct on precipitating factors. Ø Diet – semisolid food. Ø Rest, Plan activities. Ø Exercise is not useful.
- 45. Nursing Interventions • Monitor respiratory status and ability to cough and deep breathe adequately. • Monitor for respiratory failure. • Maintain suctioning and emergency equipment at the bedside. • Monitor vital signs. • Monitor speech and swallowing abilities to prevent aspiration. • Encourage the client to sit up when eating. • Assess muscle status. • Instruct the client to conserve strength. • Plan short activities that coincide with times of maximal muscle strength. • Monitor for myasthenic and cholinergic crises. • Administer anticholinesterase medications as prescribed. • Instruct the client to avoid stress, infection, fatigue, and over-the counter medications. • Instruct the client to wear a Medic-Alert bracelet. • Inform the client about services from the Myasthenia Gravis Foundation.
- 46. q Téllez-Zenteno JF, Hernández-Ronquillo L, Salinas V, Estanol B, da Silva O (2004). "Myasthenia gravis and pregnancy: clinical implications and neonatal outcome".BMC Musculoskeletal Disorders 5: 42. doi:10.1186/1471-2474- 5-42. PMC 534111. PMID 15546494. Retrieved 10 July 2008 Definition Epidemiology Pathophysiology Clinical Features Precipitating events Classification Diagnosis Differentials Treatment Rehabilitation References REFERENCES q Seybold ME (1986). "The office Tensilon test for ocular myasthenia gravis". Arch Neurol 43 (8): 842–3.doi:10.1001/archneur.1986.0052008 0080028.PMID 3729766 q McGrogan A, Sneddon S, de Vries CS (2010). "The incidence of myasthenia gravis: a systematic literature review". Neuroepidemiology 34 (3): 171–183.doi:10.1159/000279334. PMID 201 30418 q Jaretzki A, Barohn RJ, Ernstoff RM, et al. (2000)."Myasthenia gravis: recommendations for clinical research standards. Task Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America".Neurology 55 (1): 16–23. doi:10.1212/WNL.55.1.16.PMI D 10891897. q Allan H. Ropper, Robert H. Brown Adams and Victor's Principles of Neurology McGraw-Hill Professional; 8 edition (29 March 2005 https://www.rnpedia.com/nursing-notes/medical-surgical-nursing-notes/myasthenia-gravis/
- 47. THANK YOU....