me007
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46.A 15-y.o. boy with hystory of severe asthma presents in emergecy department in obvious respiratory distress.
After admission and multiple nebulizer treatments, he develops nausea, vomiting and weakness.
stadies reveal K+ 2,6 mEq/L and U waves on ECG Which of the following medications may have elicit these symptoms?
a.albuterol
b.ipratropium
c.prednisone
d.theophylline
e.zileuton
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| Palaniappan
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Is it albuterol-A?Beta 2 agonist-->Hypokalemia?
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| Ancylostoma
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D Theophylline
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| me007
Forum Guru
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A - correct.
beta-agonists such as albuterol may cause potassium to shift into cells, resulting in hypokalemia.
This may lead to toECG abnormalities due to destabilization of cardiac cell membranes, the classic example of which are U waves.
D-incorrect.
Theophylline may also cause cardiotoxicity but does not result in hypokalemia.
I do not understand concept about beta agonists -> hypokalemia.
If somebody could help to clear it up.
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| Ancylostoma
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interesting, i'm 0 For two. Didnt know that it could cause hypokalemia. good question, what question bank is it from ?
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| babydoc4usmle
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beta2-agonist causes increase in insulin secretion (stimulation of beta-cells in pancreas), which in turn causes increase in K+ upake by cells (by increase in cellular Na/K ATPase activity in response to increased insulin) --> HYPOKALEMIA, so it must be A
prednisone also causes hypokalemia, but rather in chronic use
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| me007
Forum Guru
Topics: 72
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Patients on insulin can have hypokalemia too, good to know, thank you, babydoc.
ok, here is another consept
beta-agonists stimulate insulin secretion.
And
beta-antagonists can cause hypoglycemic episodes - caution in diabetics
not really clear for me.
To Ancylostoma
it is First Aid Q&A book - 1000 qs
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| babydoc4usmle
Forum Guru
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by different mechanism - beta2-blockers inhibit glycogenolysis, glyconeogenesis --> hypoglycemia, especially on extra-insulin, that is why be careful in diabetics
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