nbme 11 question anyone know this one?

[sadaca]

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A 3 yr old is brought to ER because he ingested his grandpa 's "heart pills" . ECG shows 3rd degree heart block with ventricular escape rhythm that resolves after giving Atropine. What drug did he ingest?

a) captopril
b)Digoxin
c) Hydrocholorthiazide
d)Isosorbide dinitrate(wrong)

I feel like it has to be Digoxin but Digoxin can cause 1st degree heart block , can't find anywhere that says it leads to 3rd degree block . Please help thank you

 

[alicealicealice]

If you take enough of it it will cause 3rd degree block. Also if you know it causes 1st heart block, you can extrapolate from that. Isosorbide dintrate is a vasodilator, and it would cause reflex tachycardia; the ACEi and the HCTZ have no direct cardiotoxicity.

Also a good point in that question is that it resolves with atropine. The mechanism of digoxin slowing down the AV node is due to (somehow)increasing vagal tone. Therefore an anti-muscarinic is a logical way to reverse its effect. This action is believed to be separate from its mechanism for increasing contractility, which is done by blocking the Na/K ATPase.

Digoxin - Wikipedia, the free encyclopedia
Less frequent adverse effects (0.1%–1%) include: acute psychosis,delirium, amnesia, convulsions, shortened QRS complex, atrial or ventricular extrasystoles, paroxysmal atrial tachycardia with AV block, ventricular tachycardia or fibrillation, and heart block.[8

 

[sadaca]

thanks alot. I know I do that so much on NBMEs. If you don't mind can I ask if you have any test taking strategy while doing NBMEs ? I am doing well on uworld b/c I know how to approach those qs but my NBMEs are barely 410's but I swear I know the material. any advice would be appreciated. Thank you

 

[alicealicealice]

Im sure lots of people have advice. NBMEs are not always as tricky as UWorld. You need to think of what point are they trying to test you on and use the answer choices to your advantage by ruling things out first.
You can always convince yourself that an answer is plausible, but only one will match the "teaching point" of the stem.
For example in this Q: No info on electrolytes, Cr, Bun, hydration status, or allergy-like sx in the stem? Immediately throw out captopril and HCTZ as those are the testable side effects.

There are 2 drugs left, both CV: the vignette describes an arryhtmia. Without knowing anything specific about the drug sfx, if you know that isosorbide acts peripherally on vasculature and digoxin affects the myocardium, then you've already got the best answer by process of elim.

 

[sadaca]

Thanks .I see what you mean. Yea I think I move away from what they are really asking . Its important to focus on what is being asked and use the answer choices to help me out. I like that. Thanks for that =)

 

[ChessMaster3000]

Not sure if there is an NBME 11 thread so I'll just post another question here:


I got the question right, however, I feel that I may as well have gotten it wrong. The answer is A, and my question is basically--are any of the other answers even correct statements/phrases? For example, gamma motorneurons release acetylcholine at their axonal temrinals--but they themselves may or may not have glutamate receptors on their dendrites (and how would we know that?). Also, Serotonin receptors in alpha motor neurons--does serotonin even modulate any motoneurons? I dont know, but if it did I could totally see it "decreasing spasticity" because it is sort of a "negative" neurotransmitters. I could go through each of the incorrect answers and give similar "what ifs"--this is precisely the type of question I expect to be all over the real test, one that CAN be figured out but requires a lot of speculation and committing fully to concepts that most medical students only have been partially exposed to. I am trying to target these questions and figure out a way to answer them more confidently.

 

[sadaca]

hi, I am not sure about the other choices, but when I saw this question I knew that they were looking for MOA of Baclofen and only A is closest to that. It acts on GABA so the other choices are just there to confuse us. I don't think we should think too much into the other choices unless they were very close then we would have to worry about narrowing it down. Hope that helps