Microbio Uworld Questions help

[theTruth_97]

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so I've been doing microbio for the last few days and I have a few questions that have really stumped me (well its more than a few but I'm not going to flood you with all of those questions lol)

Here are my main ones- if anyone could answer these that would be great!

1) Does C. diff cause watery diarrhea or bloody? in FA 2015 (172) its listed as watery which was what I had learned as well, but on Uworld there was a question where it was classified as bloody diarrhea

2) There's an excellent question on Uworld about predicting what the stool sample will contain- if its an invasive bacterial species then it'll contain leukocytes while if it can cause bloody diarrhea without invasion (like through toxins) then the stool sample will just contain RBCs and watery diarrhea stool samples will be just mucus with sloughed off epithelial cells......but then the answer also explains how stool samples of intestinal parasitic infections can contain Charcot-Leyden Crystals: it goes onto list those crystals being present in Strongyloids, Ancolystoma, Ascaris, Toxocara, and Trichinella but then says NOT in Giardia or Entamoeba.....my question is why won't the crystals appear in the stool sample for giardia or entamoeba as well?

3) Do we have to learn life cycles of parasites? Obviously the more we study the better our score but since I'm super crunched for time do you think this is a "high yield" topic?

Thanks!! 🙂

 

[dfib slim]

1). Both. Classically watery but can also be bloody.
2). Parasites can cause the eosinophilia but protozoa such as giardia and entamoeba usually do not.
3). I would say that's low yield, except for maybe malaria and ascaris. Vectors and unique clinical symptoms are probably the high yield for parasitology.

 

[theTruth_97]

Thanks a lot!!

 

[Jabbed]

so I've been doing microbio for the last few days and I have a few questions that have really stumped me (well its more than a few but I'm not going to flood you with all of those questions lol)

Here are my main ones- if anyone could answer these that would be great!

1) Does C. diff cause watery diarrhea or bloody? in FA 2015 (172) its listed as watery which was what I had learned as well, but on Uworld there was a question where it was classified as bloody diarrhea

2) There's an excellent question on Uworld about predicting what the stool sample will contain- if its an invasive bacterial species then it'll contain leukocytes while if it can cause bloody diarrhea without invasion (like through toxins) then the stool sample will just contain RBCs and watery diarrhea stool samples will be just mucus with sloughed off epithelial cells......but then the answer also explains how stool samples of intestinal parasitic infections can contain Charcot-Leyden Crystals: it goes onto list those crystals being present in Strongyloids, Ancolystoma, Ascaris, Toxocara, and Trichinella but then says NOT in Giardia or Entamoeba.....my question is why won't the crystals appear in the stool sample for giardia or entamoeba as well?

3) Do we have to learn life cycles of parasites? Obviously the more we study the better our score but since I'm super crunched for time do you think this is a "high yield" topic?

Thanks!! 🙂

1. Brush border enzyme / actin polymer toxins causes watery diarrhea with the potential for occult GI bleeding. Profuse amounts of watery diarrhea can also damage the rectal lining and lead to small amounts of visible lower GI bleeding (hematochezia). Hematochezia rarely occurs in the setting of c. dif. There is also the concern of fulminant colitis with bowel perforation, although this distinction should be evident from the vignette.
2. My eyes glaze over any time the discussion turns to fungi/parasites so I won't even venture a guess.
3. Life cycle of the malaria parasites for sure (particularly the cycles of RBC lysis in falciparum vs vivax/ovale). Also the whole egg vs larva mechanism of ingestion is important as it leads to wildly different clinical presentations for the same parasite.

 

[syoung]

had a strongyloides presentation as well as chagas (which can lead to mega-organs all over, is a cause of DCM), so they may be worth refreshing quickly