Myasthenia Gravis Flashcards
What is myasthenia gravis?
An autoimmune disease characterised by antibodies to the nicotinic acetylcholine receptors
What are the symptoms of myasthenia gravis?
Weakness of limbs
Drooping eyelids
Diplopia
Difficulty smiling or chewing
Difficulty swallowing
Change in speech
When are symptoms typically worst in MG?
At the end of the day
What condition is myasthenia gravis associated with most commonly?
Thymic hyperplasia
What investigations are carried out in myasthenia gravis?
ACh receptor antibodies
CT chest (for thymoma)
Single fibre elecetromyography (EMG for single muscle fibres)
What is the first line medical management of MG?
Long acting cetylcholinesterase inhibitors
What is the first line long acting acetylcholinesterase inhibitor used in MG?
Pyridostigmine
(neostigmine may also be used)
What other management options are available?
Immunosuppression - prednisolone or azathioprine
Thymectomy
What other antibodies can cause MG?
MuSK antibodies
LRP4
What is the treatment of a myasthenic crisis?
IV immunoglobulins
Plasma exchange
What condition is myasthenia gravis a paraneoplastic syndrome of?
Thymoma
What is lambert-eaton syndrome?
A myasthenic syndrome that is a paraneoplastic syndrome of small cell lung cancer
What is the difference between myasthenia gravis and lambert-eaton syndrome?
MG worsens with exercise and activity, whereas lambert-eaton syndrome improves with exercise
What medications exacerbate MG?
Penicillamine
Quinidine
Beta blockers
Lithium
Phenytoin
Antibiotics
- Gentamicin
- Macrolides
- Quinolones
- Tetracyclines
