NMJ Disorders Flashcards
Safety factor at normal NMJs
EPP amplitudes dec during repetitive muscle contraction so less amount of ACh is released, but it’s still above threshold and gives adequate muscle contraction
Autoimmune disorder of post-synaptic NMJ
Myasthenia gravis
2 NMJ disorders that affect the pre-synaptic NMJ
Botulism and Lambert Eaton
target of Ab for myasthenia vs lambert eaton
myasthenia - AChR
lambert eaton - voltage gated Ca channel
myasthenia under electron microscopy
loss of architecture/folding of post-synaptic NMJ
initial sxs of myasthenia
ptosis, diplopia, dysarthria, dysphagia
is myasthenia symmetrical?
not always
neonatal myasthenia
healthy newborns of myasthenic moms have sxs until maternal antibodies wash out of their system
myasthenic crisis
profound weakness that may cause quadriplegia w/ patient unable to speak/swallow/breathe
triggers of myasthenic crisis
infection or systemic illness
diff dx for myasthenic crisis
extensive brain infarct, guillan barre, acute paralysis from spinal cord lesion (via inflamm or tumor)
how are sensation and reflexes affected w/ myasthenic crisis?
they’re normal
most specific diagnostic test for myasthenia
serum AChR Ab
2 Ab for myasthenia
AChR Ab MuSK Ab (tyrosine kinase)
high doses of AChE inhibitors can give
cholinergic crisis (weakness, sweatiness, salivation, diarrhea, urination) "wet sxs"
