Myasthenia Gravis Exam (Questions With A+ Solutions)
Myasthenia _______ is an autoimmune transmission disorder --> causes
weakness of voluntary muscles, affects communication btwn a motor neuron
& muscle cell (at neuromuscular junction); has no effect on sensation or
coordination Right Ans - gravis
myasthenia gravis is probably caused by sensitized ___ helper cells that cause
an autoantibody-mediated attack on the acetylcholine receptors --> decreased
amount of receptor-rich areas, decreased number of receptors, and widened
synaptic space --> impaired transmission of signals across neuromuscular
junction Right Ans - T
the antibodies that attack in myasthenia gravis are present in 80-90% of
people with MG. These people usually have either ______ hyperplasia or a ______
tumour (probably d/t the fact that antibodies are produced in the thymus
gland) Right Ans - thymic
symptoms of myasthenia gravis include ______ (drooping eyelid), diplopia
(double vision), and later maybe generalized weakness of all extremities,
respiratory muscles (affecting vital capacity), and the face and throat
(affecting swallowing, chewing, speech, and facial expressions) Right Ans -
ptosis
myasthenia gravis' weakness and fatigue ________ with continued activity
because each time acetylcholine is released from the presynaptic membrane,
the endplate potential (depolarization) decreases even more Right Ans -
increases
myasthenia gravis Dx includes Hx and physical exam, the anticholinesterase
test, _____ stimulation tests, and an investigation of acetylcholine receptor
antibodies Right Ans - nerve
__________ test - acetylcholine breakdown is prevented by the
anticholinesterase agents (enzyme inhibitors) --> acetylcholine levels increase
Right Ans - anticholinesterase
, nerve __________ tests record the targeted muscle's electrical activity after
stimulation. Pts with myasthenia gravis have a 15% decrease in successive
action potentials. Right Ans - stimulation
the third way to diagnose myasthenia gravis is by administering an ____. In
90% of cases, the MRI shows enlargement of the thymus gland (a site of
acetylcholine receptor antibody production) Right Ans - MRI
management of myasthenia gravis includes improving Fx, and reducing &
removing circulating ________ by administering anticholinesterase agents,
immunosuppressive therapy, plasmapheresis, and thymectomy. Right Ans -
antibodies
aka plasma exchange - used to treat exacerbations of myasthenia gravis;
removal, separation of blood cells and plasma, tx, and replacement of plasma
with a plasma substitute --> temporary decrease in the concentration of
circulating antibodies (sustained by cholinesterase inhibitors, corticosteroids,
immunosuppressive drugs or a combination) Right Ans - plasmapheresis
________ crisis = a sudden increase in myasthenia gravis symptoms and
weakness; occurs when muscle weakness becomes very severe - enough to
cause difficulty with ventilation and severe bulbar (face and throat muscle)
weakness.
May be d/t stress (d/t infection, emotional or physical trauma such as surgery,
pregnancy, alcohol ingestion, cold exposure, or improper doses of Tx drugs
(anticholinesterase drugs)) Right Ans - myasthenic
neuromuscular disorder characterized by fluctuating muscle weakness and a
predisposition to rapid fatigue Right Ans - Myasthenia Gravis (MG)
1. ptosis (drooping eyelids)
2. difficulty swallowing
3. skeletal muscle weakness Right Ans - MG common symptoms
difficulty breathing --> possibly respiratory failure Right Ans - MG
symptom with severe form
reversible cholinesterase inhibitor Right Ans - neostigmine
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