myasthenia gravis

Question 1

what is myasthenia gravis

Answer 1

autoimmune disorder resulting in insufficient function acetylcholine receptors

Question 2

presentation of myasthenia gravis

Answer 2

muscle fatigability
- diplopia, ptosis, proximal muscles, dysphagia

Question 3

conditions associated with myasthenia gravis

Answer 3

thymomas
autoimmune disorders: pernicious anaemia, autoimmune thyroid, rheumatoid, SLE
thymic hyperplasia

Question 4

investigations for myasthenia gravis

Answer 4

single fibre electromyography: high sensitivity
CT thorax for thymoma
antibodies to acetylcholine receptors: AChR antibodies, MuSK antibodies, LRP4 antibodies

Question 5

management of myasthenia gravis

Answer 5

long-acting acetylcholinesterase inhibitors- pyridostigmine first line
patients may require immunosuppression
- prednisolone
thymectomy

Question 6

management of myasthenic crisis

Answer 6

plasmapheresis
IV immunoglobulins

Question 7

drugs that may exacerbate myasthenia gravis

Answer 7

penicillamine
quinidine, procainamide
beta-blockers
lithium
phenytoin
antibiotics: gentamicin, macrolides, quinolones, tetracyclines