Myasthenia Gravis

MYASTHENIA GRAVIS MYASTHENIA GRAVIS • • • •

Rare disorder which affects neuromuscular transmission of voluntary muscles of body Defect in transmission of nerve impulse at neuromuscular junction Affects women particularly 20-30 years old Characterized by extreme weakness and fatigue – particularly of voluntary muscles o Cannot hold heads up

ETIOLOGY • • •

Don’t know cause Considered to be an autoimmune disease in which antibodies act against acetylcholine receptor site thus impairing neuromuscular transmission A problem at the neuromuscular junction

PATHOPHYSIOLOGY •

Due to decreased secretion of acetylcholine, or an increase in cholinesterase at myoneural junction, the transmission of impulses from nerve to muscle cells is defective

CLINICAL MANIFESTATIONS • • • • • • • • • • •

Progress slow and insidious Extreme muscular weakness relieved by rest Severe fatigue that is also relieved by rest Diplopia Ptosis o Drooping of the eyelids Sleepy masklike expression o Difficulty smiling Weakness of speech and chocking (HRF aspiration) Laryngeal and pharyngeal muscle weakness Mouth hangs open Resp distress Maysthenic crisis

DIAGNOSIS •

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Tensilon Injection Test o Tensilon – Neastigmin, Prostigmin o Should have great increase in muscle strength within seconds of injection, but only temporarily Physician will do this test EMG o Electromyography, shows weak muscles not specific to Myasthenia

MANAGEMENT • • •

No Known cure Aimed at: o Giving anticholinesterase drug to improve remaining function o Reducing and removing circulating antibodies Drug Therapy: o Prostigmin or Mestinan o These drugs increase the available concentration of acetylcholine at the neuromuscular junction, thus increasing muscular response to nerve impulses to improve strength. o MEDS should be taken at prescribed time daily. Ideally 1 hour before meals so that swallowing is adequate before mealtime o Failure to adhere to this schedule may result in dyspnea, resp distress, and inability to swallow. MEDS AS SCHEDULED o Medication is highly individualized – patient adjust their own medication o Avoid muscle relaxants o Immunosuppresive therapy  For severe cases  May decrease production of antireceptor antibody  Corticosteroids will suppress the patients immune response, thereby decreasing the amount of blocking antibody o Plasmapherises  Will produce a temporary reduction in titer of circulating antibodies o Thymectomy  Surgical removal of the Thymus gland  The thymus produce ActiR antibodies in MG Surgical removal may lead to remission. But takes 2-10 years

MYASTHENIC CRISIS VS. CHOLINERGIC CRISIS •

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Myasthenic Crisis o Too Little Medication  Acute Respiratory Distress  Can’s speak or swallow Cholinergic Crisis o Too Much Medication  Acute Respiratory Distress It is difficult to distinguish but the 2 crises both can result in respiratory distress which is a medical emergency. Also paralysis of muscles for swallowing and increase in Myasthenic symptoms MD will to tenslin test to see if under medicated

Emergency Management • Keep Airway open • Suction oral secretions • Trach kit • Elevate head and shoulders • Keep calm

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Support respiratory function as needed

PROGNOSIS • •

Can live long productive life with adequate treatment Course of disease varies by remission and exacerbation

NURSING CARE • •

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Work with nutrition Ineffective airway clearance - Resp Assessment o Monitor o Keep HOB elevated o Get meds on time o May need a trach at bedside Impaired Physical Mobility - Assess weakness HRF Injury HRF Aspiration o Small frequent feeding o If they rest in between the energy builds up acetochylione Educate and support

Frequent rest periods