clar697
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A previously healthy 24-year-old woman comes to the emergency department because of diarrhea, nausea, flatulence, and bloating for the past 5 weeks. Bowel movements are accompanied by abdominal cramping. She has not traveled out of the United States. Tympanic temperature is 37 degrees C (98.6 degrees F). Bowel sounds are increased. Test of stool for occult blood is negative. Which of the following is the most likely causal organism?
A) Bacillus cereus
B) Campylobacter jejuni
C) Cryptosporidium parvum
D) Gardia lamblia
E) Shigella sonnei
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| bactitech
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I will say D - Giardia, only because a friend of mine and her husband had these exact symptoms and their well was contaminated with Giardia. The child of one of our pathology residents came back from a trip to India with bloating and gas and had Giardia.
I went to a Parasitology workshop once YEARS ago, and they said that any diarrhea of >4 weeks standing should always be checked for Giardia.
What amazes me is how many exams we gets for O&P who do not have the history, have rock hard stools and they have ordered O&P on them - OR how many terrible looking fecal specimens we get that have everything BUT stool culture ordered on them.
When you guys are checking out diarrhea in your patients - TAKE A GOOD HISTORY before ordering stool tests willy nilly. If they are having blood and mucus, bacteria are a much better bet than an O&P test. Stools with blood mucus may have Shigella. Grossly bloody stools may have E. coli O157:H7. I can't tell you how many times O&P has been the only test ordered on these type of specimens.
Lecture finished....
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| jorgefhoyos
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I would go with B because the stem says she has NOT travelled outside of the US.
Campylobacter is the most common causative agent of diarrhea in the US. Even before Giardia, Salmonella and Shigella. But it is self limiting in 3-5 days.
But the 5 weeks is more indicative of Giardia. So I think you're right.
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| supra
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Campylobacter is an invasive organism,blood in stool positive.
GIARDIA -ruled out coz not travelled out of USA
Shigella again bloody diarrrhea
cryptosporidium,(not sure though)coz young female -HIV is a possibility.,what say folks?
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| microsporus
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D
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| drms
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B
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| eddyheart
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D is the correct answer. None of the others produce those symptoms. Keep in mind the patient has 5 weeks history of diarrhea. Giardia lamblia is the only agent posted that causes persistent or chronic diarrhea.
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| Aashi
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Without a doubt it is Giardia Lamblia-------------->D
Not travelled outside US is not a strong factor to rule out giardia,.. Backpackers, hikers, and campers who drink unfiltered, untreated water ,Swimmers who swallow water while swimming in lakes, rivers, ponds, and streams are all prone to get giardia, it is not exclusively seen only in international travellers..
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| bactitech
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Giardia lamblia is the most common parasite found in the U.S. Our laboratory only performs a Giardia antigen/Cryptosporidium antigen test on stools ordered for O&P. A full O&P is done only if the patient has persistent diarrhea or a travel history outside of the U.S. or other possible mitigating factor.
The statement that Giardia is ruled out because the patient had not travelled outside the U.S. is patently wrong. Please review this page from the CDC:
http://www.cdc.gov/ncidod/dpd/parasites/giardiasi...
Geographic distribution of Giardia is worldwide. We report any positive Giardia antigen to the Dept. of Health and ultimately to CDC's MMWR report for tracking.
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