Myasthenia gravis

Myasthenia gravis

1. MYASTHENIA GRAVIS

2. INTRODUCTION Myasthenia gravis   (MS)is derived from  Greek  meaning " muscle“ " weakness " is an autoimmune  disorder.

3. Definition Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction characterized by fluctuating weakness of certain muscle groups.

4. incidence Myasthenia gravis occur three times more common in young women , but at older ages both sexes are equally affected.

5. E tiology MG is caused by auto immune process in which antibodies attack Acetylcholine receptors ( AChR ) , resulting in a decreased number of Ach receptor sites at the neuromuscular junction.

6. Other etiology Idiopathic Thymus tumors found in 15 % of patients.

7. PATHOPHYSIOLOGY

8. AUTOANTIBODIES MYONEURAL JUNCTION ATTACKS THE ACTIVITY OF ACETYLCHOLINE RECEPTORS DECREASED Ach RECEPTORS IN NEUROMUSCULAR JUNCTION MUSCLE WEAKNESS

9. CLINICAL MANIFESTATION DIPLOPIA PTOSIS WEAKNESS OF FACE AND THROAT MUSCLE CAUSES DIFFICULTY IN CHEWING AND SWALLOWING. GENERALISED WEAKNESS HOARSE VOICE

10. C/M CONT… DYSPHONIA WEAKNESS IN ALL EXTREMITIES DECREASED VITAL CAPACITY AND RESPIRATORY FAILURE DUE TO INTERCOSTAL MUSCLE WEAKNESS.

11. PTOSIS

12. Diagnostic studies History and physical examination Electromyogram Blood studies to find auto antibodies. Tensilon test CT or MRI shows thymus gland enlargement

13. Tensilon test Tensilon test- This test is used to diagnose Myastenia gravis and to differentiate  myasthenic crisis  from cholinergic crisis by intravenous administration of   Edrophonium (tensilon) . Edrophonium is an effective  acetylcholinesterase inhibitor  which will reduce the muscle weakness by blocking the enzymatic effect of acetyl cholinesterase enzymes, prolonging the presence of acetylcholine in the synaptic cleft.

14. Diagnosis of Myasthenia gravis Most myasthenia patients will show a significant improvement in muscle tone within 30 to 60seconds after injection and the muscle improvement lasts 4 to 5 minutes.

15. Differentiate between  myasthenic crisis from cholinergic crisis In cholinergic crisis ,muscle tone does not improve after administration of tensilon and muscle twitching may be noted around the eyes and face ,which will worsens the patients condition. But in myasthenic crisis tensilon injection temporarily improves the condition .

16. MANAGEMENT

17. Drug therapy Anticholinesterace drugs- Eg ; neostigmine , pyridostigmine Corticosteroids – prednisone are used to suppress immune response. Immunosuppressant agents- cyclophosphamide antibiotics: antipsychotics

18. Surgical management Thymectomy-it is performed because thymus gland appear to enhance the production of AChR antibodies in myasthenia gravis patients.

19. Other therapy Plasmapheresis -it is the removal of plasma contains components causing or thought to cause disease . The blood cells and antibody-containing plasma are separated; then the cells and a plasma substitute are reinfused .

20. OTHER MANAGEMENT MECHANICAL VENTILLTORY SUPPORT by non invasive BIPAP INVASIVE VENTILLTORY SUPPORT

21. complications Myasthenic crisis   it is an acute exacerbation of the disease process characterized by severe generalized muscle weakness and respiratory failure.

22. NURSING MANAGEMENT

23. NURSING DIAGNOSIS INEFFECTIVE BREATHING PATTERN RELATED TO INTERCOSTAL MUSCLE WEAKNESS AS EVIDENCED BY DECREASED VITAL STASTITICS. IMPAIRED VERBAL COMMUNICATIONRELATED TO WEAKNESS OF THE LARYNX ,LIPS AND MOUTH AS EVIDENCED BY INABILITY TO TALK

24. CONT.. IMBALANCED NUTRITION LESS THAN BODY REQUIREMENTS RELATED TO IMPAIRED SWALLOWING AS EVIDENCED BY DECREASED FOOD INTAKE. ACTIVITY INTOLERENCE RELATED TO MUSCLE WEAKNESS AND FATIGABILITY AS EVIDENCED BY INABILITY TO PERFORM DAILY ACTIVITIES.