micro q

[MudPhud20XX]

A 28 yr old while male presents to clinic with a chief complaint of fatigue and fever. The fatigue started 2 weeks ago and has progressively been getting worse. He is not able to play basketball as long as he used to and has difficulty climbing the six flights of stairs to his apt. He also started a low grade fever around the same time. His maximum temp has been 38.7C. He has no allergies and takes no meds. He has a hx of asthma and Raynaud phenomenon. One month ago he was involved in a bar fight; he suffered a hand laceration after punching the individual in the mouth. He drinks alcohol on the weekends and does not smoke. Physical exam reveals a thin, pale male. Lungs are clear to auscultation bilaterally. On cardiac auscultation, a grade 3 systolic murmur is noted; previous medical charts made no mention of a murmur. Which of the following is most likely responsible for the pt's current condition?

A. gram negative rod
B. gram positive, catalase neg. cocci
C. gram positive catalase neg. optochin resistant cocci
D. gram positive catalase positive cocci
E. gram positive yeast

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[TheBDP]

GNR. Probably Eikenella corrodens from the bar fight.

 

[TBV]

C. Viridans strep

Lives in the mouth. Also one of the most common types of subacute bacterial endocarditis

 

[zhopv10]

^ C was also my thought, viridan strep from the mouth fits: not super fast progression and a subacute bacterial endocarditis


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[worldbeater]

Same thought, strep viridans. Although I would still have to guess, because I have to review that stupid gram positive diagram. So obnoxious. Anyways
for subacute bacterial endocarditis, the following are the most important points to know:

Most common, due to strep viridans
Roth spots
Janeway lesions (toes)
Osler Nodes (fingers)
Splinter hemorrhages
Endocariditis
Mycotic aneurysm (septic emboli)

Acronym: MR JOSE (and throw an 'M' in there afterwards)

 

[BamaNicole]

This is what confused me on this particular question. Strep Viridans normally affects previously damaged heart valves, right? The question stem says that there was no mention of a murmur before so I assumed that he had no damaged valves before this happened. I believe that Strep Viridans is right and I believe that I answered that with this question but now that I'm rereading it it doesn't seem right.

Can anyone shed some light on that?

 

[Reperfused]

Is this question from UWorld?
I'm kinda confused between C (strep Viridans) and D (staph aureus).
Viridans definitely makes more sense. But 2 points confuse me. As mentioned above, Viridans more likely in previously damaged heart valves (which is not in this case). And systolic murmur means Tricuspid Regurg. which occurs in staph aureus endocarditis.
Please let us know what's the correct answer and why. Thanks

 

[TBV]

Is this question from UWorld?
I'm kinda confused between C (strep Viridans) and D (staph aureus).
Viridans definitely makes more sense. But 2 points confuse me. As mentioned above, Viridans more likely in previously damaged heart valves (which is not in this case). And systolic murmur means Tricuspid Regurg. which occurs in staph aureus endocarditis.
Please let us know what's the correct answer and why. Thanks

I don't think tricuspid regurg is specific to staph aureus. I think it's more indicative of where the bug is coming from. And by that I mean that it's coming from the systemic circulation and therefore hits the tricuspid first. As far as damaged vs not damaged I'm not sure

 

[chillaxbro]

Is this question from UWorld?
I'm kinda confused between C (strep Viridans) and D (staph aureus).
Viridans definitely makes more sense. But 2 points confuse me. As mentioned above, Viridans more likely in previously damaged heart valves (which is not in this case). And systolic murmur means Tricuspid Regurg. which occurs in staph aureus endocarditis.
Please let us know what's the correct answer and why. Thanks

Why does systolic murmur have to be tricuspid? Mitral is more common and is also systolic

 

[zhopv10]

A systolic murmur can just as easily be mitral regurg (since we weren't given the location it's heard best at). Staph I think would be more acute probably, but your right it would fit the previously intact heart valve more. Staph aureus in tricuspid you'd be thinking IV stuff anyway. I haven't looked it up but I would assume viridans usually acts on damaged valves but in some cases maybe it doesn't have to? Idk the previously non damaged heart valves is a good point


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[Chilladosis]

so i get the typical board prompt has the "guy got in a bar fight, got the hand lacerated, got endocarditis" suggestive of eikenella. I understand that strep viridans also lives in the mouth, but classically dental procedures --> strep viridans. but we assume that the guy's heart valve should be normal, because we were not told that it is "damaged." damaged heart - thinking of strep viridans.

whats the main thing to differentiate the viridans from eikenella?
both can cause endocarditis etc. so symptoms should present similar.

is the onset of eikenella different from strep viridans?
the two weeks from an inciting event when symptoms start suggest more of a subacute presentation rather than acute (thus ruling out a staph aureus)

i feel like i would have to lean on the classic presentation of this type of endocarditis (bascially what did this guy do that got him the endocarditis) and go with eikenella - gram neg rod.

 

[jqueb29]

so i get the typical board prompt has the "guy got in a bar fight, got the hand lacerated, got endocarditis" suggestive of eikenella. I understand that strep viridans also lives in the mouth, but classically dental procedures --> strep viridans. but we assume that the guy's heart valve should be normal, because we were not told that it is "damaged." damaged heart - thinking of strep viridans.

whats the main thing to differentiate the viridans from eikenella?
both can cause endocarditis etc. so symptoms should present similar.

is the onset of eikenella different from strep viridans?
the two weeks from an inciting event when symptoms start suggest more of a subacute presentation rather than acute (thus ruling out a staph aureus)

i feel like i would have to lean on the classic presentation of this type of endocarditis (bascially what did this guy do that got him the endocarditis) and go with eikenella - gram neg rod.

In this particular question, the thing that immediately jumped out to me was optochin resistance (thanks Sketchy Micro). The 2 high-yield associations with optochin you need to remember is that S. pneumo is optochin sensitive and S. viridans is optochin resistant.

 

[Reperfused]

ok guys, thanks for clearing my misconception. You're right it can be TR or MR both. I was just ruling out mitral valve pathology because Viridans occurs usually with mitral valve prolapse and pt.'s valves were normal in this case. Anyway, it can still be MR, I get it now. So it's definitely not staph aureus.

 

[TheBDP]

In this particular question, the thing that immediately jumped out to me was optochin resistance (thanks Sketchy Micro). The 2 high-yield associations with optochin you need to remember is that S. pneumo is optochin sensitive and S. viridans is optochin resistant.

Where are you seeing optochin resistance?

 

[zhopv10]

Hmm ya that is a good point with the eikenella, could very well be the answer. It causes a culture negative endocarditis and is associated with human bites....
That being said viridans are also in the mouth and also cause subacute endocarditis on damaged valves... I almost think you need more info but I would be inclined to go for A now with the eikenella


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[MudPhud20XX]

Hmm ya that is a good point with the eikenella, could very well be the answer. It causes a culture negative endocarditis and is associated with human bites....
That being said viridans are also in the mouth and also cause subacute endocarditis on damaged valves... I almost think you need more info but I would be inclined to go for A now with the eikenella


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Indeed, the answer is A. good discussion guys. Thanks for the feedback!