Myasthenia gravis (Ascending Disease)
- 1. Myasthenia Gravis Mr.Sachin Dwivedi M.SC. Medical surgical Nursing K.G.M.U Institute of Nursing , Lucknow
- 3. Myasthenia Gravis The name myasthenia gravis, which is Latin and Greek in origin, means "grave, or serious, muscle weakness.“ Autoimmune disease affecting the neuromuscular junction. Not a brain disorder – brain functions normally Characterized by fluctuating muscle weakness and fatigability Disease may be generalized or ocular specific.
- 4. Definition Myasthenia gravis, an autoimmune disorder affecting the myoneural junction, is characterized by varying degrees of weakness of the voluntary muscles. It is an autoimmune disorder, in which weakness is caused by circulating antibodies that block acetylcholine receptors at the postsynaptic neuromuscular junction, inhibiting the excitatory effects of the neurotransmitter acetylcholine throughout neuromuscular junctions.
- 5. Causes Idiopathic. Autoantibodies that destroys acetylcholine receptors. Thymus tumors found in 15% of patients
- 6. Incidence MG affects 14 per 100,000 people in the United States Can affect any age group Women – peak incidence 20's to 30's Men – peak incidence 50's to 60's
- 7. PATHOPHSIOLOGY Resulting in voluntary muscle weakness that escalates with continued activity Impair the ability of acetylcholine to bind to receptors. Act against the nicotinic acetylcholine receptor Antibodies attack Acetylcholine (ACH) receptors at the motor end plate Development of auto- antibodies Due to auto-immune response.
- 9. CLINICAL MANIFESTATION Affects any of the muscles that control voluntarily, certain muscle groups are more commonly affected than others Eye, face, throat, neck, limb muscles The hallmark of myasthenia gravis is fatigability Dysarthria. Dysphagia. Ptosis. Diplopia Nasal-sounding speech Worsening muscle weakness
- 10. DIAGNOSTIC EVALUATION History:- Physical examination:- Edrophonium test (Tensilon) Blood analysis:- Repetitive nerve stimulation Single-fiber electromyography (EMG) Imaging scans:
- 11. Physical Examination Muscle strength and tone. Coordination. Sense of touch and impairment of eye movements.
- 12. Anticholinesterase test Edrophonium chloride (Tensilon) is injected intravenously, 2 mg at a time to a total of 10 mg. 30 seconds after injection, facial muscle weakness and ptosis should resolve for about 5 minutes. This immediate improvement in muscle strength after administration of this agent represents a positive test and usually confirms the diagnosis.
- 13. Blood analysis Elevated levels of acetylcholine receptor antibodies. Anti MuSK(Muscle- Specific Kinase) antibody.
- 14. Repetitive Nerve stimulation Repetitive nerve stimulation, which repeatedly stimulates a person’s nerves with small pulses of electricity to tire specific muscles. Muscle fibers do not respond as well to repeated electrical stimulation.
- 15. Single-fiber electromyography (EMG) It considered the most sensitive test for myasthenia gravis, detects impaired nerve-to- muscle transmission.
- 16. Imaging scans CT Or MRI: Its shows thymus enlargement.
- 17. 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. Alternate sips of liquid to avoid food from sticking AVOID eating chewy or dry crumbly foods
- 18. Pharmacological Management Immunosuppressive Therapy Prednisone Azathioprine Acetylcholinesterase Inhibitors First line of therapy Neostigmine bromide (Pyridostigmine) Edrophonium chloride (Tensilon) Plasmapheresis Immunoglobulin Therapy
- 19. Surgical management Thymectomy: (surgical removal of the thymus gland) can produce antigen-specific immunosuppression and result in clinical improvement.
- 20. COMPLICATION Myasthenic Crisis:- A myasthenic crisis is an exacerbation of the disease process characterized by severe generalized muscle weakness and respiratory and bulbar weakness that may result in respiratory failure.
- 21. Myasthenic Crisis VS. Cholinergic Crisis Myasthenic Crisis Under medication Increased HR/BP/RR Bowel and bladder incontinence Decreased urine output Absent cough and swallow reflex May need mechanical ventilation Temporary improvement of symptoms with administration of Tensilon Cholinergic Crisis Overmedication Decreased BP Abd cramps N/V, Diarrhea Blurred vision Pallor Facial muscle twitching Constriction of pupils Tensilon has no effect Symptoms improve with administration of anticholinergics (Atropine)
- 22. Nursing Interventions Maintain patent airway Assess swallowing to prevent aspiration Keep appropriate equipment available at the bedside: Oxygen, suction, Ambu bag, endotracheal intubation Promote energy conservation measures Consult Physical Therapy for medical equipment needs (i.e.walkers, wheelchairs)
- 23. Nursing Interventions Consult OT for assistive devices to facilitate ADLs Consult with speech and language therapist if weakening facial muscles impact communication Monitor I/O, serum albumin levels, and daily weights Know the signs and symptoms of both Myasthenic Crisis Administer Medications as per order.
- 24. Patient Teaching Teach patient/family disease process, complications, and treatments Teach patient about their medications uses dosage etc. Teach medications to use with caution that is muscle exacerbation Beta blockers, calcium channel blockers, quinine, quinidine, procainamide, some antibiotics, neuromuscular blocking agents
- 25. Prognosis Chronic disease with periods of exacerbation and sometimes remissions . Disease course is highly variable. Symptoms respond well to treatment and in most cases the patient can live a normal or nearly normal life. Ocular Myasthenia has the best prognosis.
- 26. Thank you