Myasthenia Gravis

Question 1

What type of condition is myasthenia gravis?

Answer 1

Autoimmune condition

Question 2

What does myasthenia gravis cause?

Answer 2

Muscle weakness

Question 3

What causes muscle weakness to worsen?

Answer 3

Activity

Question 4

What causes muscle weakness to improve?

Answer 4

Rest

Question 5

What type of reaction is myasthenia gravis?

Answer 5

Type 2 hypersensitivity reaction

Question 6

What age of women are affected?

Answer 6

20-30

Question 7

What age of men are affected?

Answer 7

60-70

Question 8

What do the B and T cell autoantibodies attack?

Answer 8

Postsynaptic acetylcholine receptors

Question 9

What happens to the signal for the muscle to contract?

Answer 9

It is blocked

Question 10

What do the B and T cell autoantibodies also activate?

Answer 10

The complement system

Question 11

What happens when the complement system is activated?

Answer 11

Muscle cell destruction

Question 12

What is the main antibody?

Answer 12

Acetylcholine receptor antibody

Question 13

What are the other 2 antibodies?

Answer 13

Muscle specific kinase antibody

LRP4 antibody

Question 14

what is the importance of Muscle specific kinase antibody and LRP4 antibody?

Answer 14

They’re responsible for the formation of acetylcholine receptors

Question 15

What is the main characteristic of myasthenia gravis?

Answer 15

Muscle weakness that gets worse as the day goes on

Question 16

What are the 4 main sets of muscles affected?

Answer 16

Ocular
Bulbar
Proximal
Axial

Question 17

What are the ocular signs?

Answer 17

Ptosis and diplopia

Question 18

What are the bulbar signs?

Answer 18

Dyphasia, Dysarthria, Dysphonia

Question 19

What are the proximal muscles affected?

Answer 19

Shoulders and thighs

Question 20

What are the axial muscles affected?

Answer 20

Neck and respiratory muscles

Question 21

Additional symptoms?

Answer 21

Slurred speech and fatigue when chewing

Question 22

How can you exacerbate ptosis?

Answer 22

Repetitive blinking

Worsened on sustained upward gaze

Question 23

What are 2 things you should look for?

Answer 23

Thymectomy scars

Forced Vital Capacity

Question 24

Why would you check forced vital capacity?

Answer 24

Due to the effect of myasthenia gravis on respiratory muscles

Question 25

What is the first line test?

Answer 25

Blood test- serum acetylcholine receptor antibodies

Question 26

Why would you do a CT of thorax?

Answer 26

Check for thymoma

Question 27

What is the TENSILON/ edrophonium test?

Answer 27

Give IV edrophonium

Question 28

What does edrophonium do?

Answer 28

Prevents the breakdown of acetylcholine providing temporary relief of weakness

Question 29

What is the first line treatment?

Answer 29

Acetylcholinesterase inhibitor (Cholinesterase)

Question 30

What are 2 examples of acetylcholinesterase inhibitors?

Answer 30

Pyridostigmine (main)

Neostigmine

Question 31

What additional medical treatment can you give?

Answer 31

Steroid- Prednisolone

Question 32

What surgical procedure may you need to carry out?

Answer 32

Thymectomy

Question 33

What is myasthenic crisis?

Answer 33

Acute worsening of symptoms

Question 34

What type of illness is myasthenic crisis usually triggered by?

Answer 34

Respiratory illness

Question 35

What can myasthenic crisis lead to?

Answer 35

Respiratory failure

Question 36

What is the main management of myasthenic crisis?

Answer 36

IV immunoglobulins

Question 37

What would you give if IV immunoglobulins fail?

Answer 37

Plasmapheresis (plasma exchange)

Question 38

Which type of drug should be avoided in someone with myasthenia gravis?

Answer 38

Beta-blockers