GI infections.txt

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GI infections.txt
2010-10-02 19:59:15

GI infections
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  1. Name three things that can cause esophagitis?
    Candida, CMV, HSV.
  2. What are three non-invasive tests to diagnose H. pylori?
    Urea breath test, serology, stool antigen test.
  3. What are three invasive tests to diagnose H. pylori?
    Endoscopic: Culture, histology, biopsy urease test.
  4. What is the first line treatment for H. pylori?
    • Two antibiotics: Metronidazole, clarythromycin
    • One PPI: Omeprazole.
  5. What is the measured fecal osmolality in osmotic diarrhea?
    Less than 2.
  6. What does STEC stand for?
    Shiga-toxin producing E. coli - (0157:H7).
  7. What is an unusual feature of E. coli 0157:H7, what medium is used to culture?
    • Does not ferment sorbitol
    • Sorbitol-MacConkey medium (SMAC): clear colonies are 0157.
  8. What are some characteristics of Salmonella?
    Gram negative, flagellated, non-encapsulated, facultative anaerobic bacillus.
  9. Where is salmonella typhi found, where does it multiply in the body, what are some risk factors?
    • Poor sanitation areas
    • Mononuclear phagocytic cells
    • HIV, decreased gastric pH.
  10. What are the four most common symptoms of typhoid?
    • Fever, weakness, anorexia, headache
    • Less common: abdominal pain, diarrhea, constipation.
  11. What are some characteristics of Shigella dysenteriae?
    • Gram-negative, rod shaped
    • fecal-oral transmission
    • greatest reservoir is humans
    • affects mostly age 1-5
    • invades host cells.
  12. What is a complication of shigellosis?
    HUS: Hemolytic-uremic syndrome.
  13. What do campylobacter bacteria look like?
    Motile and curves S-shape, or spiral rod.
  14. What are some clinical features of Yersinia enterocolitica?
    • fever, diarrhea, abdominal pain (RLQ)
    • Rectal bleeding, ileum perforation
    • Reactive polyarthritis
    • Erythema nodosum
    • Exudative pharyngitis.
  15. What are three characteristics of Yersinia enterocolitica?
    Gram negative, Non-lactose fermenter (NLF), bacilli.
  16. What is the most common health-care associated diarrhea?
    Clostridium Difficile.
  17. What are three characteristics of C. difficile?
    • Gram + bacilli
    • Anaerobe
    • Spore Forming.
  18. What are the three reserviors for C. difficile?
    Soil, environment, colonized people.
  19. When does C. difficile infection usually occur?
    After course of broad-spectrum antibiotics (killing normal intestinal flora).
  20. What is a characteristic of its pathogenesis?
    Forms a pseudomembrane on the colon (pseudomembranous colitis - PMD).
  21. What is one severe complication of CDAD (C. difficile Associated Disease)?
    Toxic Megacolon.
  22. What are four diagnostic methods for C. difficile?
    • Cytotoxin assay
    • Immunoassay (ELISA) for toxin
    • Stool culture
    • PCR.
  23. What are the two toxins released by C. difficile?
    • Toxin A: enterotoxin, causes tissue damage, fluid secretion, inflammation (not necessary for virulence)
    • Cytotoxin B: 1000x more potent than A, activate release of cytotoxins from monocytes.
  24. What are some characteristics of CMV?
    • Largest genome of all herpes viruses (betaherpesvirus)
    • ubiquitous
    • most cases sub-clinical.
  25. What are some clinical features of CMV infection?
    • Mononucleosis-type syndrome
    • Interstitial pneumonia
    • Hepatitis
    • GBS
    • meningoencephalitis.
  26. What stain is used to visualize Cryptosporidium?
    Modified Kinyoun acid-fast stain -- red sphere.
  27. What are some clinical manifestations of Cryptosporidia infection?
    • Voluminous, watery diarrhea - without blood or leukocytes -- associated with cramps, fatigue, anorexia
    • Can be fulminant and rapidly fatal in HIV or immunocompromised patients.
  28. What can infect that is found in raspberries?
  29. What stain is used to visualize cyclospora?
    • Acid Fast
    • Should be done several times - low excretion.
  30. What is a characteristic of Microsopidiosis?
    Caused by 6 different genera of obligate intracellular, monocellular parasites.
  31. What stain is used in the stool examination to diagnose microsopidiosis?
    Weber's chromatrope-based stain.
  32. Name two liver flukes?
    • Clonorchiasis
    • Opisthorchiasis.
  33. How do you diagnose liver flukes?
    • Ultrasound of liver
    • Examination of stools for eggs.
  34. In who do most cases of spontaneous bacterial peritonitis present?
    Patients with ascites from chronic liver disease.