Myasthenia Gravis Flashcards
Myasthenia Gravis is an a________ response against…
autoimmune
NMJ post-synaptic receptors
What type of hypersensitivity reaction is myasthenia gravis?
Type 2
True or false: often patients with Myasthenia Gravis wake up feeling fine and by the end of the day feel weak
True
Myasthenia gravis affects ______ muscle
skeletal
In myasthenia gravis, what symptoms occur when the extraocular muscles are affected?
Diplopia (double vision)
Ptosis
What groups of people are at higher risk of Myasthenia Gravis?
20-30 y/o women
and
60-70 y/o men
(unclear why this bimodal distribution)
What does acetylcholine, released from motor neuron, bind to on the muscle cell membrane at a NMJ?
Nicotinic acetylcholine receptor
In myasthenia gravis, what cells make the autoantibodies that bind to the nicotinic ACh receptors on muscle cell membrane?
B cells
Give a summary of the pathophysiology of Myasthenia gravis
Type II hypersensitivity reaction results in B cells producing autoantibodies that bind to the nicotinic ACh receptors on the muscle cell membrane of NMJs, blocking ACh from binding. Therefore, muscle won’t contract.
A minority of people with Myasthenia Gravis produce the harmful antibody called muscle specific receptor t_____ k____ antibodies
tyrosine kinase
What do muscle specific receptor tyrosine kinase antibodies attack?
Proteins inside muscle cells also leading to destruction of healthy cells
Rarely, a p______ can generate an immune response which results in generation of autoantibodies (Lambert Eaton Syndrome)
paraneoplasm
What are symptoms of Myasthenia Gravis?
Muscle weakness
Weak eye muscles, diplopia
Ptosis
Myasthenic snarl (difficulty smiling)
Jaw fatigability
Swallowing difficulty
Speech fatigability
What worsens the muscle weakness in Myasthenia Gravis?
Exertion (better with rest)
Where do symptoms in Myasthenia Gravis start?
In head and neck and goes down to lower body
