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What is myasthenia gravis?
- Autoimmune chronic disease
- Affects nervous system causing fatigue/muscle weakness
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Cause
- Autoantibody attack of acetylcholine receptors at muscle end plate
- nervous impulses are not transmitted & muscles cannot contract
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Patho
- Hyperplasia of thymus gland-in some cases a tumor (thymoma)
- Hyperthyroidism has strong association
- Exacerbation period- heat, infection, stress, fatigue, cathartics
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Motor manifestations
- Fatigue
- Muscle weakness- resolves c rest
- Poor posture
- Ptosis
- Diplopia
- Loss of bowel/bladder control
- Resp compromise
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Sensory manifestations
- Muscle aches
- Paresthesia
- Reduced smell/taste
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Diagnostics
- Thyroid function
- SPE
- Acetylcholine receptor testing
- Tensilon testing
- Electromyography
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Nonsurgical interventions
- Respiratory support
- Promote mobility
- Drug therapy
- Plasmapheresis
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Myasthenia crisis (exacerbation)
- Often caused by infection or not enough anticholenergic drug
- Pt at risk for anticholinesterase drug overdose
- Resp system is compromised
- Pt might require mechanical ventilation
- S/S-increased resp, HR, BP; anoxia; cyanosis; B/B inc; decreased urine output; absence of cough/swallow reflex
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Cholinergic crisis (acute exacerbation)
- Increased muscle weakness due to overdose of anticholinesterase drug.
- S/S-N/V; diarrhea, abd cramps, blurred vision, pallor, facial muscle twitching, hypotension
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Surgical intervention
Thymectomy
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