Myasthenia Gravis

Question 1

what is myasthenia gravis?

Answer 1

autoimmune disease

characterized by fluctuating weakness of certain muscle groups

Question 2

course of disease of myasthenia gravis

Answer 2

variable
short-term remission
stabilization
severe, progressive

Question 3

risk factors of myasthenia gravis

Answer 3

age 10-65

women

Question 4

pathogenesis of MG

Answer 4

antibodies attach ACh receptors
decrease ACh receptor sites a neuromuscular junction
prevents ACh molecules from attaching and stimulating muscle contractions

Question 5

clinical manifestations of MG

Answer 5

fluctuating weakness of skeletal muscle

strength returns after resting

Question 6

muscles involved in MG

Answer 6

eyes/eye lids
facial
speaking
breathing

Question 7

myasthenic crisis

Answer 7

acute exacerbation of muscle weakness

triggered by infection, surgery, emotional distress, pregnancy/menses

Question 8

major complication of MG

Answer 8

breathing muscle weakness

Question 9

MG pharmacology

Answer 9

immunosuppressants (steroids)

cholinesterase inhibitors

Question 10

how do cholinesterase inhibitors work

Answer 10

prevent inactivation of ACh by cholinesterase

intensify effects of ACh released from motor neurons to increase motor strenght

Question 11

when to give cholinesterase

Answer 11

30-45 min prior to eating to strengthen swallowing

oral, iv, im

Question 12

neostigmine

Answer 12

cholinesterase inhibitor
used for MG
enhances cholinergic action by facilitating transmission of impulses across neuromuscular junctions`

Question 13

in therapeutic doses neostigmine affects

Answer 13

both muscarinic and nicotinic recptors

Question 14

GI tract cholinergic vs anticholinergics

Answer 14

chol- increased motility, diarrhea

anti- decreased motility, constipation

Question 15

mouth cholinergic vs anticholinergics

Answer 15

chol- increased secretions

anti- dry mouth

Question 16

bladder cholinergic vs anticholinergics

Answer 16

chol- urinary urgency

anti- urinary retention

Question 17

heart cholinergic vs anticholinergics

Answer 17

chol- bradycardia

anti- tachycardia

Question 18

lungs cholinergic vs anticholinergics

Answer 18

chol-bronchial constriction

anti- bronchodilation

Question 19

eyes cholinergic vs anticholinergics

Answer 19

miosis (constrictions), mydriasis (dilation)

Question 20

neostigmine- muscarinic side effects

Answer 20

increased secretions and GI motility
urinary urgency
bradycardia
bronchial constriction
miosis, near sidedness

Question 21

neostigmine- neuromuscular (nicotinic) side effects

Answer 21

increased muscle contractions- therapeutic doses
reduced contraction- toxic doses
toxicity will lead to cholinergic crisis

Question 22

cholinergic crisis

Answer 22

extreme muscle weakness or paralysis

s/s of excessive muscarinic stimulation

Question 23

treatment of cholinergic crisis

Answer 23

mechanical ventilation

atropine

Question 24

what is the antidote for muscarinic symptoms?

Answer 24

atropine

Question 25

what should a patient with cholinergic crisis wear at all times?

Answer 25

a med alert braclet

Question 26

MG crisis

Answer 26

not enough stimulation or acetylcholine
muscles are not stimulated and weak
leads to respiratory failure

Question 27

what causes cholinergic crisis?

Answer 27

too much acetylcholine or nystigmine

overstimulation of muscles and muscles wear out leading to respiratory failure