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DU PA Stool Studies
Duke PA Stool Studies
Question | Answer |
---|---|
how does a FOBT work | based on oxidation of guaiac by hydrogen peroxide, resulting in development of a blue color on card when exposed to heme found in stool |
3 days prior to FOBT avoid | red meats, >250mg vitamin C |
7 days prior to FOBT avoid | NSAIDS/Aspirin (>325) |
FOBT specimens are ideally innoculated onto card at least __ days prior to developing test | 3 |
If immediate results are required for FOBT, wait at least __ minutes prior to development | 3-5 |
causes FOBT false positives | red meats, aspirin, NSAIDS, alcohol, steroids, anticoagulants, chemotherapeutics, iodine preps |
causes FOBT false positives | vitamin C >250mg/day |
__ detects presence of leukocytes | methylene blue |
__ indicative of invasive infective organisms or other inflammatory bowel disorders | fecal leukocytes |
stool cultures are not routinely __ | gram stained |
fecal leukocytes will be absent in | norovirus, rotavirus, CMV, ETEC and EHEC, giardia lamblia, Entamoeba histolytica, Cryptosporidium, S. aureus, B. cereus, C. perfringens |
infectious causes of present fecal leukocytes | shigella, campylobacter, EIEC, Entero, Ivasive E. coli |
an inflammatory protozoal infection. intact fecal leukocytes may not be seen | Entamoeba hisotlytica |
an inflammatory viral agent (usually in immunocompromised patients) causes ulceration with viral inclusion bodies within cells on intestinal biopsy | CMV |
predominant causative enterotoxin for Pseudomembranous colitis | C. difficile toxin A |
when assessing a patient for C. diff it is the __ that you are looking for | toxin |
three most commonly screened pathogens in stool cultures | salmonella, shigella, and campylobacter |
when doing a stool culture a fresh or unpreserved stool should be delivered to the lab in <__ hours | 2 |
IFA indirect immunofluorescence assay utilizes monoclonal antibodies to identify __ | giardia cysts |
__ is extrememly sensitive and specific for H. pylori | urea breath test |
when looking for __ don't send for culture, you look for indirect evidence for the organism | giardia cysts |
for detection of malabsorption disorders which result in steatorrhea (celiac/tropical sprue, Whipples dz, ZE, Crohn's) used more as a screening tool due to more specific testing for each disorder | fecal fat studies |
flock of seagulls on gram stain | campylobacter |
diarrhea acute in onset and persisting for less than 2 weeks is most commonly caused by __ | infectious agents, bacterial toxins, or drugs |
community outbreaks of diarrhea suggest __ | viral etiology or shared food source |
day care attendance or exposure to unpurified water may result in infection with | giardia, or cryptosporidium |
watery, nonbloody diarrhea associated with periumbilical cramps, bloating, nausea, or vomiting suggests __. because tissue invasion does not occur there will be no fecal leukocytes | small bowel source that disrupts normal absorption and secretory processes |
prominent vomiting suggests __ | viral enteritis or S. aureus food poisoning |
the presence of fever and bloody diarrhea indicates __ | colonic tissue damage caused by invasion or a toxin |
diarrhea that originates in the __ is high volume | small intestine |
diarrhea that originates in the __ is low volume | large intestine |
organisms that may cause fever and bloody diarrhea from invasion of colon tissue | shigella, salmonella, campylobacter, yersinia or toxins (C. difficile, E. coli O157:H7) |
organisms that may cause watery non-bloody diarrhea from disruption of small bowel activity | enterotoxigenic E. coli, S. aureus, B. cereus, C. perfringens, giardia |
a shiga-toxin producing non-invasive organism most commonly acquired from contaminated meat | E. coli O157:H7 |
watery, nonbloody diarrhea associated with periumbilical cramps, bloating, nausea, or vomiting. fecal leukocytes often not present | noninflammatory diarrhea |
fever and small volume bloody diarrhea, associated with LLQ cramps, urgency, and tenesmus. fecal leukocytes often present | inflammatory diarrhea |
if diarrhea worsens or persists for more than 7 days, stool should be sent for __ | fecal leukocytes or lactoferrin determination, ovum and parasite evaluation, and bacterial culture |