39. Myasthenia Gravis Flashcards
(20 cards)
What is Myasthenia Gravis
autoimmune neuromuscular disease that causes weakness in the skeletal muscles
- worsens after periods of activity and improves after periods of rest
What antibodies does Myasthenia Gravis affect
Antibodies against nicotinic acetylcholine receptors between the nerve and muscles
MG is sometimes caused by _____
MuSK (Muscle-Specific Kinase)
- prevents nerve impulses from triggering muscle contractions
MG:
_____ gland causes autoimmune disease
thymus
s/s MG
- ocular myasthenia: eye muscle weakness
- Ptosis
- Diplopia
- dysphagia
- inability to cough or gag
- SOB
- slurred speech
- weakness in arms/hands/finger/legs/neck
Does HR increase or decrease with MG
increase
Does BP increase or decrease with MG
increase
What is myasthenia crisis
severe muscle weakness and resp failure
4 ways to test MG
- tensilon test
- blood tests
- electrodiagnostics
- CT or MRI
Describe purpose of tensilon test
- Will differentiate between myasthenic vs cholinergic crisis
- Edrophonium briefly relieves weakness by blocking the break down acetylcholine and increasing levels at the neuromuscular junction
- ↑ acetylcholine at the neuromuscular junction
What to prepare for tensilon test
- 10mg tensilon prepared lasting 10 min
- have 2mg atropine in case of cholinergic crisis
Two types blood tests for MG
- acetylcholine
- Anti-MuSK antibody
type of electrodiagnostic for MG
single fiber electromyography (EMG)
purpose of CT or MRI for MG
detect presence of a thymoma
2 meds used for MG and examples of each
- cholinesterase inhibitors (neostigmine & pyridostigmine)
- autoimmune treatments (prednisone, use 4-6 wks then taper)
side effects of MG
- ↑ mucus salivation, urination, sweating, abdominal cramps, muscle twitching, nausea, vomiting, diarrhea, decreased pupil size, slowed or slurred speech, convulsion, dizziness, headache, low blood pressure, shortness of breath
Therapeutic levels of Cholinesterase Inhibitors _____. Toxic levels _____.
- Produce mild stimulation
- depress the CNS
How to treat toxic levels of cholinesterase inhibitors
Treat with respiratory support and atropine
Non-pharmacologic treatments of MG
- plasmapheresis
- IV immunoglobulin
- thymectomy
- hydrotherapy
s/s Cholinergic Crisis
- Increased salivation, lacrimation, sweating, urination, abdominal cramping, emesis.
- Bronchospasm, tachycardia
- Muscular weakness, fatigue, fasciculation leading to paralysis
- Respiratory muscle weakness, respiratory failure
