NBME 20 Answers ↦
FA 2020 page 186: Asplenic patients (S. pneumoniae>> H. influenza > N. meningitidis)
I agree with you, only possible logic for their answer:
the qualifier asplenic makes the "ShIN" pathogens more likely, even though Ecoli can cause gram negative sepsis and DIC. FA 2019 pg 127
Also it says s pneumo causes sepsis specifically in asplenic patients Pg 136
To be honest, the only reason I got this right (because I really was thinking E.Coli as well), is that I ended up remembering the MOPS part of the Sketchy, and I couldn't remember if he said that it was the number 1 cause of all of them or not, and ended up clicking it. It's pretty shitty they don't offer explanations for these.
I thought this too but it seems like Strep pneumo is just more specifically associated with infection in asplenic/sickle cell patients than E. Coli is. Just one of those classic associations. There's a sickle in the Sketchy Strep pneumo sketch, vs. no sickle in the E.Coli sketch.
E. coli causes pneumonia by aspiration, for which this patient had no risk factors. For USMLE, if they don't say the patient is vaccinated, you can assume they are NOT. Just because she has a history of splenectomy following trauma does NOT mean she had to been vaccinated--don't fill in the history for the patient, only use the information they give you.
also DIC more often seen with G- bacteria right???? That's why I chose E.coli instead of S.pneumonia
Agreed -- went with E. Coli like a dingus, just because I didn't associate DIC with S. Pneumo. Thought it was too easy.
Isn't E. Coli also an encapsulated organism? What makes Strep pneumo more likely in this question just because its the more common cause?
Pseudomonas aeruginosa is encapsulated as well. I think the right answer has to do with DIC but why?
The only reason i found was S. pneumo is more common, I went with Pseudomonas because of the "overwhelming sepsis" :(
Everyone is correct about the Encapsulated microbes, but this is one of those of "MOST LIKELY",
and by far the most likely is S.Pneumo>>H.infl>N.Mening. (omitting that patients with history of splenectomy must be vaccinated.
Gram negative are more common in DIC my friends
Correct me if I am wrong, but I am pretty sure that E. coli is NOT a common cause of pneumonia because it must be aspirated to enter the lung. Thus, only patients with aspiration risk (e.g. stroke, neurogenic conditions) would be at a chance of getting E. coli pneumonia.