406 E2 - Myasthenia Gravis

Question 1

what type of disease is myasthenia gravis

Answer 1

an autoimmune disorde (type II)

Question 2

myasthenia gravis

Answer 2

characterized by fluctuation weakness of certain muscle groups (ocular, bulbar, limb, & respiratory)

Question 3

myasthenia gravis course of disease

Answer 3

spontaneous case that goes into remission -> back to baseline -> stabilization -> relapse -> severe relapse w/ progression

Question 4

what causes weakness in myasthenia gravis

Answer 4

antibody mediated immunological attack directed in the postsynaptic membrane of the neuromuscular junction
breakdown in communication between the nerves and the muscles

Question 5

myasthenia gravis risk factors

Answer 5

-gender (women)
-age: 10 to 65yrs

Question 6

myasthenia gravis etiology

Answer 6

possibly a genetic component that is gets triggered

Question 7

myasthenia gravis pathogenesis

Answer 7

antibodies attack ACh receptors -> decrease in ACh receptor sites at the neuromuscular junction -> this prevents ACh molecules from attaching and stimulating muscle contraction
body is producing enough AHc but not enough receptor sites

Question 8

myasthenia gravis: CM

Answer 8

insidious onset
-fluctuating weakness of skeletal muscle
-strength comes back after resting
-difficulty swallowing
-drooling
-impaired nutrition / aspiration
-impaired ventilation
-muscle fatigue after exercise

Question 9

what muscles are involved in myasthenia gravis

Answer 9

-eyes/eyelids
-facial
-speaking (mouth, face)
-breathing (neck)

Question 10

when do clinical manifestations typically first appear w/ myasthenia gravis

Answer 10

pregnancy, postpartum, or after some anesthesias

Question 11

myasthenic crisis

Answer 11

acute exacerbation of muscle weakness

Question 12

myasthenic crisis triggers

Answer 12

infection, surgery, emotional distress, pregnancy/menses, inadequate pharmacotherapy or other drugs

Question 13

what is our biggest concern w/ a myasthenic crisis

Answer 13

weakness of respiratory muscles leading to respiratory depression which puts pt at high risk for respiratory arrest

Question 14

myasthenia gravis pharmacotherapy

Answer 14

-immunosuppressants (steroids)
-cholinesterase inhibitors

Question 15

how do cholinesterase inhibitors work

Answer 15

-prevent inactivation of ACh by cholinesterase
-intensify the effects of ACh released from motor neurons, increases muscle strengthen

Question 16

cholinesterase inhibitor nursing considerations

Answer 16

-give 30 minutes prior to eating to strengthen swallowing muscles
-not a cure, sx relief

Question 17

what class is neostigmine

Answer 17

cholinesterase inhibitor (anti cholinesterase)

Question 18

neostigmine indication

Answer 18

myasthenia gravis

Question 19

neostigmine MOA

Answer 19

enhances cholinergic action by facilitating transmission of impulses across neuromuscular junctions

Question 20

neostigmine, in therapeutic doses, affects which receptors

Answer 20

muscarinic and nicotinic receptors

Question 21

cholinergic SE (GI, mouth, bladder, heart, lungs, eyes)

Answer 21

GI: increased motility, diarrhea
Mouth: increased secretions
Bladder: urinary urgency
Heart: bradycardia
Lungs: bronchial constriction
Eyes: miosis (constriction)

Question 22

anticholinergic SE (GI, mouth, bladder, heart, lungs, eyes)

Answer 22

GI: decreased motility, constipation
Mouth: dry mouth
Bladder: urinary retention
Heart: tachycardia
Lungs: bronchial dilation
Eyes: mydriasis (dilation)

Question 23

atropine can be used for what

Answer 23

comfort care to dry up secretion so they don’t choke on it

Question 24

neostigmine SE: muscarinic

Answer 24

-increased secretions, GI motility
-urinary urgency
-bradycardia
-bronchial constriction
-miosis (near sighted)

Question 25

neostigmine SE: neuromuscular

Answer 25

-therapeutic: increased muscle contraction
-toxic doses: reduced contraction
-cholinergic crisis w/ toxicity

Question 26

cholinergic crisis

Answer 26

-extreme muscle weakness or paralysis
-S/s of excessive muscarinic stimulation

Question 27

treatment for cholinergic crisis

Answer 27

-mechanical ventilation
-antidote: atropine

Question 28

individuals w/ myasthenia gravis should always wear what

Answer 28

med alert bracelet

Question 29

MG crisis vs Chol crisis

Answer 29

MG: not enough stimulation (muscles are weak bc no stim)
Chol: too much ACh or nystigmine (muscles overstim and wear out)
both lead to respiratory failure

Question 30

differentiating between MG and Chol crisis

Answer 30

give edrophonium (a short acting cholinesterase inhibitor that will temporarily increase ACh) -> if they’re in MG they will improve and if they’re in chol they will worsen