Myasthenia Gravis Flashcards
what type of disease is myasthenia gravis(MG)
autoimmune neuromuscular disorder
what is myasthenia gravis characterised by
severe muscular weakness and progressive fatigue
what other autoimmune diseases is MG associated with
SLE, rheumatoid arthritis, thyrotoxicosis
briefly describe the mechanism that causes MG
auto-reactive antibodies(auto-IgG) bind with postsynaptic acetylcholine receptors on muscle cells
at what age can/does MG occur
can occur at any age
most often middle/later in life
what are the causes of MG
idiopathic(90%), thymic tumour(10%)
describe the typical onset of MG
typically insidious
what muscles are usually affected first in myasthenia gravis patients
muscles of eyes, face, mouth, throat
what muscles are usually the initial presentation of MG, in around 60% cases
ocular(eye) muscles
in late stages of MG what muscles are affected
all muscles are weak, can lead to life-threatening impairment of respiration
what is involved in the activation of the auto-reactive B cells in MG
CD4+ T helper cells and ACh receptor self antigens
what are the CD4+ T helper cells activated by in MG development
activated by unfolded ACh receptor subunits expressed by thymic epithelial cells
what does activation of auto-reactive B cells in MG result in
production of anti-AChR IgG auto antibodies
