5.6 Myasthenia Gravis Flashcards

1
Q

myasthenia gravis is caused by antibodies that block __________ receptor

A

cholinergic

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2
Q

myasthenia gravis onset peaks in 20s for _______ and in 50s for _______

A

women, men

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3
Q

15% of patients with myasthenia gravis also present with _________

A

thymoma

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4
Q

most common symptoms of MG are __________, and progress to generalized MG within ____ years

A

ocular, 3

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5
Q

most SPECIFIC test for MG, presence of antibodies is nearly diagnostic

A

acetylcholine receptor antibody test

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6
Q

inject ACh-esterase inhibitor, allows more acetylcholine in NMJ to compete, ptosis improves, good sensitivity and bad specificity

A

edrophonium test

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7
Q

depletion of acetylcholine and amplitude of action potentials decrease, painful

A

repetitive stimulation

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8
Q

most sensitive test for MG, single muscle fiber action potential, firing time of 2nd fiber in a motor unit later due to delay in NMJ transmission, jitter or blocked action potential

A

single fiber EMG

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9
Q

most specific test for MG?

A

acetylcholine receptor antibodies

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10
Q

most sensitive test for MG?

A

single fiber EMG

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11
Q

suppress immune system, high doses make them worse initially, use adjucant chemo like drugs to help with immunosuppression

A

corticosteroids

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12
Q

stops production of abnormal antibody, negative feedback

A

IVIG

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13
Q

mestinon 1st line, used prior to steroids, GI side effects treated with anticholinergics, lasts hours

A

pyridostigmine

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14
Q

remove antibodies, most effective, good for crisis or non-responsive to steroids

A

plasmapheresis

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15
Q

80% of patients have ______ abnormalities

A

thymus

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16
Q

lymphocytes in thymus produce acetylcholine receptor antibodies, performing a __________ causes slow and gradual fall in antibodies

A

thymectomy