GI tract infections Flashcards
what is the main pathogen that causes esophagitis? what is the appearance?
candida albicans
white nonulcerative plaques
what are the symptoms of esophagitis?
- dysphagia with or without odynophagia
- retrosternal pain
- fever (variant)
treatment: candida
- oral fluconazole 14-21 days (preferred)
- IV echinocandin (effective) or amphotericin B (toxic)
treatment: HSV
acyclovir
treatment: CMV
- IV gangciclovir 3-6 weeks
- oral valganciclovir
what are the noninvasive diagnostic tests for H. pylori?
- urea breath test
- stool antigen test
- serology (does not distinguish reliably between active and past infection)
what are the invasive studies for H. pylori?
- biopsy urease test (first choice)
- histology
- culture
standard treatment: H. pylori
- previously prescribed PPI
- clarithromycin
- amoxicillin
what therapeutic options are used if the standard H. pylori regimen fails (sequential, alternate)?
sequential:
- rabeprazole + amoxicillin x5 days
- rabeprazole + clarithromycin + tinidazole x5 days
alternate:
- bismuth subsalicylate + TCN + metronidazole + omeprazole
chronic diarrhea is diarrhea lasting how long?
over 4 weeks
curved gram negative rod that causes diarrhea
vibrio cholerae
swimming pool - risk of what infection?
cryptosporidium
stream water - risk of what infection?
giardia
which organisms causing acute diarrhea have a preformed toxin?
bacillus cereus
s. aureus
c. perfringens
clinical presentation: non inflammatory diarrhea
large volumes
watery stools
s/s of dehydration
clinical presentation: inflammatory diarrhea
dystentery - small quantities of blood and mucous, often with fever
lab findings: non inflammatory diarrhea
- fecal leukocyte studies NEGATIVE
- acidosis
- azotemia
lab findings: inflammatory diarrhea
fecal leukocyte studies positive
which organisms causing acute diarrhea are cytotoxin producers?
c. difficile
hemorrhagic e. coli
what is the most sensitive test for for epidemiological c. difficile studies? which one is used the most?
stool culture
PCR toxin gene detection (DNA molecular assay)
what is the drug of choice for an initial episode of mild-moderate CDI?
metronidazole
what is the drug of choice for an initial episode of severe CDI?
vancomycin
what is the drug of choice for severe complicated CDI?
oral vancomycin with or without meteronidazole
what are the treatments for lower GI infections?
- supportive (fluids, electrolytes)
- bismuth subsalicylate or antiperistaltic agents if watery diarrhea without fever or blood in stool (if appropriate)
- pathogen specific antibiotics when indicated
what is a defining features of e. coli O:157 H7 / hemorrhagic diarrhea?
lack of fever
