Myasthenia Gravis and Lambert Eaton Flashcards
What is MG?
An autoimmune condition of muscle weakness that gets worse with activity and improves with rest
What are the links of MG?
thyoma in men
AI in women
What is the pathophysiology of MG?
ACh receptor antibodies bind to postsynaptic NMJ receptors blocking them and preventing ACh stimulating muscle contraction
What is the most common presentation of MG?
Ocular weakness
When are symptoms best in MG?
morning or after rest
What is the diagnosis of MG?
Serum AChR +ve
MuSK antibodies may be +ve
Gold = tensilon (edrophonium) test - injection of drug should relieve weakness
What is the acute management of MG?
Neostigmine
What are some long-term management options for MG?
Steroids - Azathioprie, Rituximab
What is given in an MG crisis?
Plasma exchange and IV Ig
What are some drugs that can worsen MG?
Beta blockers, lithium, phenytoin, gentamicin
What is often underlying in LE?
Small cell lung cancer
What is most affected in LE?
Proximal muscles - lower limbs
What is the pathophysiology of LE?
Antibodies produced against Na+ channels of SCLC also target Ca2+ channels of the NMJ reducing Ach release
What is the management of LE?
Amifampridine - allows more Ach release
Prednisolone
IV Ig
Plasma exchange
