58 - Myasthenia Gravis

Question 1

myasthenia gravis

Answer 1

autoimmune disease of neuromuscular junction

Question 2

myasthenia gravis is characterized by…

Answer 2

fluctuating weakness of certain skeletal muscle groups

-weakness with increased muscle use

Question 3

MG pathophysiology

Answer 3

antibodies attack ACh receptors> fewer ACh sites> decr stimulatn of muscle contractn

Question 4

90% of MA pt has _____ in their serum

Answer 4

anti-AChR antibodies

Question 5

___ + ___ are common in pt w MG

Answer 5

-thymic hyperplasia + tumors

Question 6

muscles are generally strongest during the ___ + worst during ____

Answer 6

• morning
• night
• rest usually restores strength**

Question 7

the first muscles involved are usually….

Answer 7

ocular muscles

• ptosis in 1 or both
• double vision
• does not progress beyond eyes in 20% of MG**

Question 8

what can exacerbate MG…

Answer 8

• fatigue
• pregnancy
• illness
• trauma
• temp extremes
• stress
• hypo-K

Question 9

drugs that can exacerbate MG…

Answer 9

• B adrenergic blockers
• quinidine
• phenytoin
• anesthetics

Question 10

myasthenic crisis

Answer 10

acute worsening of muscle

Question 11

myasthenic crisis can be triggered by

Answer 11

• resp infectn
• surgery
• emo distress
• pregnancy
• certain drugs
• beginning tx w corticosteroids

Question 12

major complications of MG

Answer 12

-myasthenic crisis
-muscle weakness>
>swallowing>aspiration
>breathing >resp insuffcnc
>res track infectn

Question 13

diagnostic for MG

Answer 13

• history + phys exam
• EMG
• tensilon test

Question 14

tensilon test results

Answer 14

after IV injection of EDROPHONIUM CHLORIDE>
>MG: rapid improvement in strength
>Cholnrgc Crisis: increased muscle WEAKness

Question 15

EDROPHONIUM CHLORIDE

Answer 15

• tensilon
• anticholinesterase agent
• blocks the enzyme that breaks down ACh

Question 16

tensilon test is for…

Answer 16

-indication of MG
or
-ID cholinergic crisis

Question 17

cholinergic crisis

Answer 17

overdose of anticholinesterase drug

Question 18

____ should be nearby during tensilon test to counteract the effects of edrophonium wen pt is experiencing cholinergic crisis

Answer 18

ATROPINE

-cholinergic antagonist

Question 19

drug therapy for MG

Answer 19

• anticholinesterase
• alt day corticostrds
• immunosuppressants

Question 20

EMG

Answer 20

may show decr response to repeated stim of hand muscles

>indicates muscle fatigue

Question 21

most successful drug in long term tx of MG

Answer 21

pyridostigmine

Question 22

surgical therapy for MG

Answer 22

thymectomy
-removal of thymus gland
indicated for most w thymoma

Question 23

other therapies for MG

Answer 23

• plasmapheresis

- IgG

Question 24

assess for ___ in myasthnic crisis

Answer 24

RESP DISTRESS

• muscle strength
• swallowing
• speech
• cough
• gag reflex

Question 25

schedule MG doses to peak during…

Answer 25

mealtime to make eating easier

Question 26

myasthenic crisis + cholinergic crisis both have…

Answer 26

• incr weakness in skeletal muscles
• ptosis
• bulbar signs (difficulty swallowing, articulating works)
• dyspnea

Question 27

difference in SYMPTOMS bw myasthenic crisis + cholinergic crisis

Answer 27

MC: improved strength after admin of edrophonium

CC: weakness after admin of edrophonium
-miosis, drool, diarrhea, n/v, ab cramps, sweat, incr bronchial secretion, lacrimation

Question 28

difference in CAUSE bw myasthenic crisis + cholinergic crisis

Answer 28

MC: exacerbation of myasthenia bc drug dose too low, nonadherence to tx, or preciptng factors

CC: overdose of anticholinesterase drugs> incr acetylcholine at receptor sites