Myasthenia Gravis

Question 1

What is myasthenia gravis?

Answer 1

A disorder of neuromuscular transmission

Question 2

What causes MG?

Answer 2

Binding of autoantibodies to components of the NMJ

Question 3

Describe the pattern of muscle weakness?

Answer 3

Worse on exertion, gets better with rest

Question 4

What other manifestation will most patients have at some point?

Answer 4

Ocular

Question 5

Where might weakness be seen?

Answer 5

Small muscles of the hands, deltoid and triceps, bulbar muscles, mastication muscles

Question 6

What might occur?

Answer 6

Seizures

Question 7

What antibodies would you look for?

Answer 7

ACh receptor antibodies

Question 8

What organ would you test?

Answer 8

Thyroid

Question 9

Describe a crushed ice test

Answer 9

Ice applied to ptosis for 3 minutes, improves in MG

Question 10

How do you manage MG?

Answer 10

Acetylcholinesterase inhibitors

Question 11

Give an example of an acetylcholinesterase inhibtor?

Answer 11

Pyridostigmine

Question 12

What are some alternatives to pyridostigmine?

Answer 12

Methotrexate, ciclosporin, tacrolimus

Question 13

What drugs can exacerbate MG?

Answer 13

Ciprofloxacin, azithromycin, propranolol, atenolol, verapamil, lithium, statins, chloroquine, prednisolone