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471 Cards in this Set
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Causative agent of nausea, vomiting (onset < 6 hr) after eating cold cuts, or potato salad, or mayonnaise, or custards?
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Staphylococcus aureus
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Rapid-onset food poisoning is mediated by what component of staphylococcus?
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Enterotoxin
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Tx of staphylococcal food poisoning?
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Rehydration
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Microbial cause of nausea and vomiting, +/- diarrhea (onset < 6 hr) after eating reheated rice?
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Bacillus cereus
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Bacterial spores are resistant to heat due to what component?
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dipicolinic acid core
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Microbial cause of nausea, vomiting, watery diarrhea w/ rapid (onset >6 hr) after eating reheated meat or gravy?
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Clostridium perfringens
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Most likely cause of persistent dyspepsia in a pt not receiving NSAIDs is
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Helicobacter pylori
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Increased risk of gastric adenocarcinoma and MALT lymphoma
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H. pylori colonization
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Indications to treat H. pylori-associated PUD
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Presence of organism
|
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Standard first-line abx for PUD due to H. pylori is
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PPI + clarith + amox
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Cause of acute onset of diarrhea with rice-water stools, vomiting, dehydration during travel to South America
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Vibrio cholerae
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Pathophysiology of cholera is due to what mechanism?
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A-B toxin causes ↑ cAMP
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13. Cholera pathogen is isolated from stool by culture on selective medium called
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thiosulfate-citrate-buffered sucrose (TCBS) agar
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14. The comma-shaped cholera organisms are microscopically similar to
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Campylobacter
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15. Tx of cholera involves
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Rehydration (tet in severity)
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16. Secretory diarrhea, fever and vomiting during travel are caused by
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Enterotoxic E. coli
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17. Secretory diarrhea w/ fatty, foul-smelling stools in campers, hikers; also day-care outbreaks is caused by
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Giardia lamblia
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18. Following ingestion of 15-25 cysts, excysted trophozoites adhere at brush border of enterocytes and contribute to malabsorption. TOW?
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Giardiasis
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19. Dx of giardiasis is confirmed by
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Stool antigen (+)
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20. Giardiasis is specifically treated with
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Metronidazole
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21. Protracted, secretory diarrhea w/ large fluid loss in AIDS is caused by (clue: acid-fast organisms)
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Cryptosporidium >> Cyclospora > Isospora
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22. Frank bloody diarrhea, after eating undercooked meats or drinking fruits drinks, is caused by prepared foods or water, contaminated w/
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E. coli O157:H7
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23. Pathogenesis of hemorrhagic enterocolitis caused by E. coli involves
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Shiga toxin (a cytotoxin)
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24. Complication of hemorrhagic enterocolitis in children
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hemolytic uremic syndrome
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25. Profuse diarrhea, fever, vomiting, and dehydration in infants is caused by
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Rotavirus
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26. Mechanism of rotaviral diarrhea involves
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Villus destruction
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27. Infantile watery diarrhea and fever are caused by
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Adenovirus 40,41
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28. Outbreak of nausea, vomiting, fever in adults is caused by
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Norovirus
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29. Cause of nausea/vomiting, abdominal cramps, diarrhea +/- bloody 12-48h after eating eggs or poultry or peanut butter?
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Non-typhoidal Salmonella
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30. Abx treatment in acute gastroenteritis due to Salmonella spp. is not warranted to avoid
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carrier (in bile ducts) state
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31. Abx used only to treat septic phase of salmonella gastroenteritis is
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ciprofloxacin
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32. Cause of fevers (>103°), headaches; macular rash on torso (“rose spots”) abdominal pain and little diarrhea later; PE: bradycardia; hepatosplenomegaly (+/-) in a pt with hx of travel (to tropics)?
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Salmonella typhi
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33. Cause of diarrhea w/ occult blood, abdominal cramping and fever, 2d after ingestion of poultry-contaminated salad
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Campylobacter jejuni
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34. Abx to treat campylobacter enteritis with high fevers in pregnancy, and HIV is
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Erythromycin
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35. Cause of dysentery-like illness with fever + abdominal cramps, tenesmus + blood & mucus in children?
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Shigella sonnei
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36. Dysentery due to invasive Shigella spp. in elderly is treated with
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Ciprofloxacin
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37. Cause of dysentery-like illness (+/- pseudoappendicitis or pseudo- crohn syndrome) in the northern region after eating cheese
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Yersinia enterocolitica
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38. Cause of dysentery-like illness in a patient w/ hx of broad-spectrum abx use
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Clostridium difficile
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39. Clostridium difficile-associated diarrhea (CDAD) is mediated by toxins
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A (enterotoxin) + B (cytotoxin).
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40. Lab confirmation of CDAD does not require stool Cx, but is based on
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EIA for stool toxins A or B
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41. Besides rehydration and cessation of inciting meds, CDAD is treated with
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Metronidazole (mild) or oral vancomycin (severe/relapse)
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42. Health-care associated (nosocomial) spread of Clostridium difficile diarrhea and protracted outbreak is due to
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Fecal-oral and/or contact w/ environmental spores
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43. Hx of abdominal pain, tenesmus, stools with mucus + blood in a patient, who recently traveled to tropics; CBC: eosinophilia. TOW?
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Amebic dysentery
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44. Stool microscopy to confirm amebic dysentery should reveal characteristic trophozoites of Entamoeba histolytica w/
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endocytosed RBCs (distinction from luminal ameba)
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45. Rx of amebic dysentery involves
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Metronidazole + iodoquinol
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46. Abscesses in liver or peritonitis in travelers w/ or w/o hx of amebic dysentery is confirmed by
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Serology for E. histolytica
|
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47. A boar hunter develops dysentery after eating meat at campsite; O & P test should reveal a ciliate parasite, known as
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Balantidium coli
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48. Most likely cause of chronic abdominal pain, diarrhea; intestinal obstruction; cholangitis; liver abscess, in children
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Ascaris lumbricides
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49. Ova & Parasite test using microscopy for oval eggs (with a thick coarse shell) in stool confirms
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ascariasis
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50. A child has stomach ache, distended abdomen, poor appetite. “Pearl-colored earthworm”-like organisms in the stool. Major immune response against this infection?
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IgE
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51. DOC of ascariasis is
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Mebendazole
|
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52. Vomiting, cramping, diarrhea, epigastric pain, weight loss in an immigrant from developing country is caused by
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Strongyloides stercoralis
|
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53. DOC of strongyloidosis is
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Ivermectin
|
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54. Pt w/ AIDS (low CD4+ counts) develops pulmonary infiltrates (+ eosinophilia) and/or gram negative sepsis. TOW?
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Invasive strongyloidosis
|
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55. Weakness, fatigue, lightheadedness, dyspnea, pruritis; pallor; iron- deficiency anemia; eosinophilia (hx of outdoor activity). TOW?
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Hookworm (Necator americanas) infection
|
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56. Fever, periorbital edema, subconjunctival hemorrhages, muscle weakness, and rash, after eating undercooked pork (Lab: eosinophilia., ↑CPK, ↑LDH &). TOW?
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Trichinellosis
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57. Abdominal pain, bloating, altered appetite after ingestion of sushi. CBC: megaloblastic anemia; leukocytosis/eosinophilia. TOW?
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Diphyllobothriasis (fish tapeworm)
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58. Dx of tape worm infection is confirmed by
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Proglottids in stool
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59. Tape worm infections are treated with broad-spectrum agent
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Praziquantel
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60. Cause of fever, lymphadenopathy, hepatosplenomegaly in an immigrant from Africa or Orient; pt recalls wading in stagnant water. RUQ ultrasound (+); CBC: eosinophilia.
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Schistosoma mansoni (Africa) S. japonicum (Far East)
|
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61. Microscopy of stool in chronic stage of schistosomiasis reveals
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Large eggs with lateral spine.
|
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62. Chronic stage of schistosomiasis is treated with
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Praziquantel
|
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63. Patient with acute jaundice is HAV IgM (+); household contact should receive for prophylaxis
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Inactivated HAV vaccine
|
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64. Patient with jaundice for < 1 week has HBsAg (+), Anti-HBc IgM (+). TOW?
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Acute HBV infection
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65. Multiple sex partners, IDU, infants born to infected mothers are risk groups for which hepatitis virus
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HBV
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66. This is an enveloped, double stranded DNA virus w/ ss-break; transmitted by infective body fluids. TOW?
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HBV
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67. This asymptomatic man has hep serology profile of HBsAg (-), Anti-HBs (+), Anti-HBc IgG (+), Anti-HBc IgM (-). TOW?
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Resolved hepatitis B
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68. This man has jaundice and is HBsAg (+) > 6 months, Anti-HBs (-), HBeAg (+), Anti-HBc IgG (+), HBV DNA > 20,000 IU/ml. TOW?
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Chronic active hepatitis B
|
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69. This man has jaundice and is HBsAg (+) > 6 months, HBeAg (+) and evidence of necroinflammation. He should receive
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Peg-IFNα 2a + lamivudine (or cidofovir)
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70. This man has no jaundice, but HBsAg (+) >6 months, Anti-HBs (-), Anti-HBc IgG (+), HBeAg (-), persistently normal ALT. TOW?
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Inactive HBsAg carrier
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71. This man, at the time of annual physical exam, reveals Anti-HBs (+) and other markers are (-). TOW?
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HBV immunized
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72. Virologic confirmation of chronic jaundice in a HBV-immunized pt w/ IDU or hemodialysis is based on
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HCV RNA > HCV IgG
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73. More chronicity of HCV (than HBV) is due to immune-evasive quasispecies generated during replication (in blood) of
|
error-prone HCV RNA virus
|
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74. Fulminant hepatitis in a patient, who has multiple sexual partners and is HBsAg (+); HBcIgM (-), can be fatal due to what?
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HDV superinfection.
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75. Cause of acute onset of jaundice, nausea, right-upper quadrant pain, hepatomegaly in pregnant women in India
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HEV
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76. Fever, arthralgia, carditis, polyarthritis, chorea, erythema marginatum; elevated WBCs or ESR/CRP. Clinical Dx is confirmed by
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Rising ASO titer
|
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77. Type II hypersensitivity due to molecular mimicry in a immunological sequel of streptococcal pharyngitis causes
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Acute rheumatic fever (ARF)
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78. ARF is diagnosed and treated with
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Anti-streptolysin O (ASO) titer and benzathine penG.
|
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79. A man with IDU has flu-like symptoms; 1-3 minor peripheral signs: conjunctival hemorrhage, Janeway lesions, Osler nodes, Roth spots, plus vegetation in tricuspid valve. Blood Cx (BCx) should yield
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S. aureus
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80. A pt w/ hx of extraction of impacted tooth 3 weeks ago now has subacute (native, mitral-valve) endocardits. BCx should yield
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Viridans streptococci.
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81. A pt w/ hx of St. Jude bypass 2 months ago has now subacute bacterial endocarditis. BCx should yield
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Staphylococcus epidermidis
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82. A pt with AIDS and recent hx of UTI has now subacute, native mitral-valve endocarditis. BCx should yield
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Enterococcus faecalis (or faecium)
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83. DOC of acute endocarditis in patient with IDU due to sensitive S. aureus (MSSA).
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Nafcillin +gentamicin
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84. DOC of acute endocarditis in patient with IDU due to resistant S. aureus (MRSA).
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Vancomycin + rifampin
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85. DOC of subacute, native mitral-valve endocarditits due to viridans streptococci.
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PenG +/- gentamicin
|
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86. DOC of subacute, prosthetic-valve endocarditis due to Staphylococcus epidermidis
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Vancomycin + gentamicin
|
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87. DOC of subacute, native mitral-valve endocardits due to Enterococcus faecalis (or faecium)
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High-dose ampicillin + gentamicin
|
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88. Patient with enterococcal bacteremia fails to respond to vancomycin. MOR of the organism
|
D-Ala-D-Ala is changed to D- Ala-D-lac
|
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89. Hx of catheter-related endocarditis, involving prosthetic or native valves. BCx (+) for budding yeast. Pt does not respond to AmphoB or fluconazole; should receive
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Caspofungin
|
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90. Patient with colon cancer has bacteremia due to
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Streptococcus bovis
|
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91. Cause of febrile, malaise, arthralgia, dyspnea, edema, palpitations. ST/T wave change, heart block, dysrhythmias; CXR: cardiomegaly
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Coxsackievirus > echovirus > Trypanosoma cruzi (Chagas)
|
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92. Cause of runny nose, red throat, and nasal pus
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Rhinoviruses
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93. Rhinoviruses and enteroviruses belong to picornavirus family, but the rhinoviruses differ from enteroviruses on
|
Growth at 22oC/noninvasive
|
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94. Rhinovirus receptor in the nasal passages and upper tracheobronchial tree is
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ICAM-1
|
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95. Rhinovirus, influenza, parainfluenza, coronavirus, RSV, metapneumovirus, and adenovirus all cause
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Upper-respiratory infections (URIs)
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96. Sinusitis, otitis, laryngitis, exacerbations of bronchitis and asthma are mostly secondary to
|
Viral URIs
|
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97. In HEENT, Streptococcus pneumoniae, non-typable Haemophilus influenzae, Moraxella catarrhalis all cause
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Acute otitis media (AOM) & sinusitis
|
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98. AOM and sinusitis are empirically treated with amoxicillin + clavulanate. Why use clavulanate?
|
Haemophilus and Moraxella are β-lactamase producers
|
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99. Cause of pharyngeal pain, dysphagia, fever; red throat + purulent exudate that responds to penicillin
|
Streptococcus pyogenes (aka: Group-A β-hemolytic Streptococcus = GABHS)
|
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GABHS is differentiated from GBBHS by what?
|
Bacitracin sensitivity
|
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Common mode of acquisition of URI due to Streptococcus
|
Infective droplets
|
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Major virulence factor with anti-phagocytic function of strep pyogenes
|
M-protein fibrils
|
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Damage in posterior pharynx and tonsils due to Streptococcus pyogenes is associated with what host response?
|
Pyogenic inflammation
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DOC of acute bacterial pharyngitis in a pt w/ Pen allergy
|
Erythromycin > clindamycin
|
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Pyogenic complication of streptococcal pharyngitis
|
Tonsillar abscess
|
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Toxigenic complication of streptococcal pharyngitis
|
Scarlet fever >> TSS (rare)
|
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Immunologic complication of streptococcal pharyngitis
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Acute rheumatic fever (ARF)
|
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Cause of fever, red throat + purulent exudate - pseudomembrane with lymphadenopathy, in a pt w/ questionable immunization
|
Corynebacterium diphtheriae
|
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Gram/special stain of Corynebacterium diphtheriae should
|
Gram(+) rods in palisade arrangements/metachromatic granules .
|
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Virulence genotype of Corynebacterium diphtheriae is
|
Transduction (phage mediated transfer of exotoxin gene)
|
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Isolate on tellurite agar culture of throat swab for a cause of diphtheria is confirmed by
|
Immunodiffusion (ELEK) assay for toxin
|
|
Mechanism of action of exotoxin of Corynebacterium diphtheriae
|
ADP ribosylation of EF-2 (inhibits protein synthesis)
|
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Damage to pharynx and cardiac myosites due to Corynebacterium diphtheriae is mediated by
|
Cytotoxicity of A-B toxin
|
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Virologic Dx of URI symptoms, fever; red throat + purulent exudate; hepato-splenomegaly, lymphadenopathy, in a teenager, is confirmed by
|
heterophile antibody (+)
|
|
Host cells preferentially infected by EBV are
|
B cells
|
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EBV is biologically similar to what class of viruses?
|
herpes viruses
|
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Host immune system controls the EBV infection, mediated by
|
CD8+ T lymphocytes
|
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Rash occurs following which antibiotic(s) to treat infectious mononucleosis?
|
amoxicillin
|
|
Burkitt's lymphoma in some African population is a B-cell tumor due to oncogenesis by
|
EBV
|
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Nasopharyngeal carcinoma, a B-cell tumor that is common in the Oriental population that consumes preserved fish, is due to oncogenesis by
|
EBV
|
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Heterophile-negative infectious mononucleosis syndrome is due to ?
|
CMV
|
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Gram-positive bacteria that cause acute otitis media (AOM)
|
Streptococcus pneumoniae
|
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Gram-negative diplococci bacteria that cause AOM
|
Moraxellar catarrhalis
|
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Gram-negative coccobacilli bacteria that cause AOM
|
Haemophilus influenzae
|
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> 7 days of nasal obstruction, rhinorrhea; purulent nasal drainage + frontal pain/tenderness is treated with
|
Amoxicillin & Clavulanate
|
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DOC for acute mastoiditis in a young child is amoxicillin & clavulanate; why?
|
Same etiology as AOM
|
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Cause of “seal-like barking” cough + episodic aphonia w/ symptoms of URI in a child
|
parainfluenza virus
|
|
Gram-stain-nonreactive organism that causes redness; purulent discharge at lid margin/eye corners, in a newborn
|
Chlamydia trachomatis
|
|
Most common cause of redness; tenderess; hyperpurulent d/c; eye stuck shut in AM, lid edema. Gram stain (+)
|
Staphylococcus aureus
|
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Cause of pharyngitis, conjunctivitis, fever with rhinitis, and cervical adenitis in a child.
|
Adenovirus
|
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Cause of burning, gritty feeling in eyes; diffuse conjunctival injection & profuse tearing + preauricular LN.
|
Adenovirus
|
|
Cause of foreign body sensation, lacrimation, photophobia, conjunctival hyperemia, and ulceration
|
HSV-2>>1
|
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Cause of severe pain and skin lesions in dermatomal pattern involving the ophthalmic division of the trigeminal nerve.
|
VZV
|
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Cause of painful, swollen, red eyes, with conjunctival hemorrhaging and excessive tearing in an outbreak
|
Enterovirus
|
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Cause of chorioretinitis in AIDS, but CMV antigen (-)
|
Toxoplasma gondii
|
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Cause of painful keratitis, chronic corneal ulcers in contact lens users, unresponsive to abx.
|
Acanthamoeba spp.
|
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In an infant w/ ?immunization, 2 wks of paroxysmal coughs, inspiratory "whoop" + post-tussive emesis. TOW?
|
Bordetella pertussis
|
|
Pertussis toxin inhibits chemotaxis via downregulation of C3a/C5a receptor, resulting in?
|
lymphocytic leukocytosis in CBC
|
|
Three major virulence factors of “whooping cough” pathogen?
|
ADP-ribosylating toxin; tracheal cytotoxin; hemolysin
|
|
Cause of fever + drooling, stridor, dyspnea in a child w/ ?immunization (pt appears septic)
|
Haemophilus influenzae b
|
|
Major virulence factor of Haemophilus influenzae associated with pneumonia and meningitis
|
Capsular polysaccharide (antiphagocytic and anti-C3b)
|
|
Since, absent spleen places host at increased risk for invasive H. influenzae infection, pre-exposure prophylaxis prior to elective splenectomy is ?
|
Hib immunization
|
|
Cause of acute exacerbation (cough, purulent sputum) in pt with chronic bronchitis (COPD); CXR: R/O pneumonia; Lab: sputum reveals Gram-negative coccobacilli.
|
Haemophilus influenzae (non capsular types)
|
|
Tx of AECB, caused by an organism that needs NAD + hematin for growth; β-lactamase (+), is
|
Ceftriaxone (severe) >. Amoxicillin-clavulanate (mild)
|
|
Most common cause of lower-respiratory infections in neonates (babies < 4 wk)?
|
Streptococcus agalactiae
|
|
Complicated illness in a newborn of a GBS-colonized mother is
|
Sepsis or meningitis
|
|
A mother colonized (recto-vaginally) w/ GBS is at risk for preterm baby or premature membrane rupture. She should receive
|
Ampicillin
|
|
An elderly comes up with an abrupt-onset fever, myalgia, headache, malaise, dry cough, sore throat and rhinitis, in winter. Illness could have been prevented w/ ?
|
annual influenza vaccine
|
|
Annual influenza vaccine protects at-risk subpopulation w/ 60% immune protection, and is composed of what 3 viruses?
|
A:H1N1 + A:H3N2 + B
|
|
Secondary spread of influenza occurs in a crowded setting (within 6 feet of infected person) via
|
respiratory droplets
|
|
Annual vaccine to prevent influenza is needed due to antigenic drift. This occurs due to what genetic mechanism?
|
Mutation
|
|
Occasionally serious pandemic of influenza occurs due to antigenic shift. This occurs due to what genetic mechanism?
|
Reassortment of 8 genomic segments
|
|
DOC of pts with influenza <48 hours is
|
Oseltamivir
|
|
Bacterial superinfection, causing pneumonia, after influenza occurs in elderly (in LTCF) due to what?
|
S. pneumoniae > S. aureus
|
|
A seriously ill young adult w/ necrotizing pneumonia, poorly responding to vancomycin, should get
|
Linezolid
|
|
Cause of febrile illness + bronchiolitis in an infant; BAL viral culture (+).
|
Respiratory syncytial virus (RSV)
|
|
RSV causes seasonal, nosocomial pneumonia outbreaks in the pediatric units via
|
Contact spread
|
|
Pathophysiology of asthmatic Sx + Sn in bronchioles in high-risk infants due to RSV involves
|
type III hypersensitivity
|
|
Inhaled anti-viral drug used in the sickest infants with bronchiolitis is
|
Ribavirin
|
|
Insidious onset of fever, dry cough, malaise and sore throat in young adults. CBC: anemia; CXR: diffuse infiltrates. TOW?
|
Mycoplasma pneumoniae
|
|
Dx of “walking pneumonia” in older children and young adults, while waiting for serology, is supported by
|
cold agglutinin (IgM Ab against RBCs) titer ≥1:32
|
|
β-lactam abx is ineffective for Tx of mycoplasma pneumonia because
|
Wall-less bacteria
|
|
A male child with mycoplasma pneumonia now has systemic rash, covering 10% of his body. TOW?
|
erythema multiforme (SJS)
|
|
Cause of upper respiratory Sx, slow onset of cough (laryngitis) >2wks + CXR: patchy infiltrate, viral serology (+)
|
Chlamydophila pneumoniae
|
|
The most common cause of community-acquired pneumonia (CAP) is
|
Streptococcus pneumoniae
|
|
Cause of rapid onset of high fever, cough, & sputum, dyspnea; tachypnea in an elderly; CXR: lobar infiltrate; CBC: pronounced neutrophilic leukocytosis with left shift, is
|
Streptococcus pneumoniae
|
|
Gram-positive diplococci from sputum from a patient with lobar pneumonia yield α-hemolytic colonies and are confirmed by
|
Capsular swelling (Quelling rxn)
|
|
α-hemolytic colonies of Streptococcus pneumoniae is differentiated from viridans streptococci definitively confirmed by
|
Optochin sensitivity
|
|
Population w/ ↑incidence of pneumococcal pneumonia is
|
AIDS
|
|
↑ incidence of colonization of what organism is seen in very young and elderly, crowding, following viral URI (↑PAF receptors), fall/winter season?
|
Streptococcus pneumoniae
|
|
Streptococcus pneumoniae is transmitted P2P by
|
Respiratory droplets
|
|
Nasopharyngeal mucosal colonization is facilitated by
|
IgA protease
|
|
Streptococcus pneumoniae reaches lungs after nasopharyngeal colonization via
|
aspiration
|
|
Major virulence factor, facilitating invasion and dissemination of Streptococcus pneumoniae is
|
Polysaccharide capsule
|
|
Pneumococcal cell wall peptidoglycans, teichoic acid elicit
|
Inflammation
|
|
↑ Lung cell injury in pneumococcal pneumonia is caused by virulence factor?
|
Pneumolysin (α-hemolysin)
|
|
Multiple myeloma, C3 deficiency, asplenia - Hg SS, COPD, diabetes, alcoholism, smokers are risk factors for mortality due to
|
pneumococcal pneumonia
|
|
Hematologic marker for poor prognosis of pneumococcal pneumonia is
|
Leukopenia
|
|
Emipiric DOC of CAP in pts at risk or w/ comorbidity is
|
Azithromycin (or levofloxacin) + ceftriaxone
|
|
Pneumonia due to highly penicillin-resistant Streptococcus pneumoniae (Pen MIC >8) should receive
|
moxifloxacin or vancomycin
|
|
Mechanism of penicillin resistance in Streptococcus pneumoniae is
|
PBP alteration by mutation
|
|
Pt w/ agammaglobulinemia or asplenia or sick-cell anemia or ↓C3 should be vaccinated with
|
Pneumococcal polysaccharide vaccine (PPSV: 23-valent)
|
|
Hx: a patient w/ serious CAD now on a ventilator, acquires bronchopneumonia >72 hrs after hospitalization. TOW?
|
Pseudomonas aeruginosa
|
|
Cause of necrotizing pneumonia >72 hrs after hospitalization of complicated viral illness
|
Staphylococcus aureus
|
|
Patients that are aspiration prone have hx of
|
dysphagia, decreased consciousness
|
|
Hx of a patient w/ seizure illness has fever, cough evolving over 2-4 wks; CXR infiltrate (+).TOW?
|
Aspiration pneumonia
|
|
Community-acquired respiratory pathogens that cause aspiration pneumonia
|
Streptococcus pneumoniae > Anaerobes
|
|
Hospital-acquired respiratory pathogens that cause aspiration pneumonia
|
Gram-negative bacilli > S. aureus +/- anaerobes
|
|
Clinical Dx of sudden dyspnea +/- cyanosis, fever, wheezing, often ARDS-like picture is
|
acid-related pneumonia
|
|
Bacterial etiology and Tx of aspiration pneumonia are determined by
|
Gram stain (polymicrobic) and culture of sputum
|
|
Empiric DOC of necrotizing pneumonia in a patient with seizure illness
|
clindamycin + levofloxacin
|
|
Targeted Abx for anaerobic aspiration pneumonia is
|
clindamycin
|
|
Pneumonia in homeless/alcoholics; Gram-positive diplococci in sputum Gram smear. TOW?
|
Streptococcus pneumoniae
|
|
Pneumonia in homeless/alcoholics; Gram-negative rods in sputum smear. TOW?
|
Klebsiella pneumoniae
|
|
Cause of pulmonary embolism in a pt with IVDU
|
Staphylococcus aureus
|
|
Common cause of pneumonia in pts with CF
|
Pseudomonas aeruginosa
|
|
Sputum of a patient with hospital-acquired pneumonia yields a Gram-negative rod that is oxidase (+). TOW?
|
Pseudomonas aeruginosa
|
|
Common cause of external otitis due to hot tub use is
|
Pseudomonas aeruginosa
|
|
A patient with diabetes has osteomyelitis after penetrating foot injury. TOW?
|
Pseudomonas aeruginosa
|
|
The most widely used anti-pseudomonal penicillin
|
Piperacillin > imipenem
|
|
The most widely used anti-pseudomonal aminoglycoside
|
Tobramicin > gentamicin
|
|
This pt >50 years, smoking hx, CMI↓ has pneumonia; diarrhea, renal failure. Urine antigen (+) for pathogen. Pt responds to azithromycin. TOW?
|
Legionella penumophila
|
|
Penicillin is ineffective against Legionnaire’s dz because
|
Intracellular organism
|
|
Individuals with defective CMI response has poor prognosis of Legionnaire’s dz because
|
Intracellular organism
|
|
Asymptomatic patient with PPD (+)
|
Latent tuberculosis infection (LTBI)
|
|
Cough > 2 wks, fever, night sweats, weight loss, hemoptysis, SOB; CXR: upper lobe infiltrate. TOW?
|
Active Mycobacterium tuberculosis infection
|
|
Oral drug regimen of choice for treatment of active TB (aka: 1st line drugs) is
|
INH+RIF+PZA+EMB (oral) + Vit B6
|
|
Pyridoxine is added to 4-drug therapy for TB to prevent
|
neuropathy (due to INH)
|
|
Pt w/ TB fails to respond to 4-drug regimen w/ INH+RIF resistance because
|
Multiply drug-resistant (MDR) TB
|
|
Pt w/ MDR-TB fails to respond to INH +RIF+FQ+an injectable drug (amikacin, capreomycin, or kanamycin) because
|
Extremely-drug resistant (XDR) TB
|
|
Cause of TB-like Dz that does not respond to 1o TB Tx regimen, in a pt. w/ AIDS
|
Mycobacterium avium – intracellulare (aka: MAC)
|
|
Cause of chronic pneumonia in a patient with cancer, receiving cytotoxic chemotherapy; lung-CT: halo/crescent sign (+)?
|
Aspergillus fumigatus
|
|
Hx of chronic pneumonia w/ lung bpsy histopathology (+) for hyphae 2-4μm wide, septate, acute- angle branching. TOW?
|
Aspergillus fumigatus
|
|
Cause of TB-like LRI in a pt with outdoor activity (Giemsa stain of bronchoscopy specimen: (+) for 2-5 μm yeasts) is
|
Histoplasma capsulatum
|
|
Pt with AIDS has blood culture (+) for histoplasmosis. DOC has effects on
|
Ergosterol in fungal cell membrane
|
|
TB-like Dz w/ ulcerative skin lesions. lung bpsy histopathology (+) for large yeast w/ broad-based bud. DOC?
|
Intraconazole
|
|
Hx of acute onset of cough, fever, infiltrate in a black male with CMI↓; histopathology of lung (+) for a large sac of endospores. DOC?
|
Fluconazole (indefinite)
|
|
Pt w/ aspiration pneumonia with cervico-facial lesion should respond to
|
Penicillin G
|
|
Granular specimen from draining fistulae from a pt with LRI on anaerobic culture should yield
|
Actinomyces israelii
|
|
Pt with AIDS or organ transplant has indolent pneumonia, w/ or w/o CNS abscess or granuloma. TOW?
|
Nocardiosis
|
|
Organism w/ characterization of Gram-positive branching, beaded, filamentous rod, weakly acid fast is
|
Nocardia asteroids
|
|
Hx of non-productive cough, fever and dyspnea evolving over 2-4 wks. CXR (+): bilateral interstitial infiltrates, hypoxemia; ↑LDH, CD4 count <200/mm3 in a MSM. TOW?
|
Pneumocystis pneumonia
|
|
DOC of pneumocystis pneumonia (PCP)
|
TMP-SMX
|
|
Pt has urinary urgency, frequency, dysuria; lab: pyuria (+) or nitrite (+). TOW?
|
Cystitis due to E. coli
|
|
Significant UTI is confirmed by semiquantitative MSU culture based on the threshold of
|
> 1,000 cfu/mL
|
|
Mode of acquisition of uropathogen is
|
Endogenous
|
|
Microbial (structure) factor favoring bacterial persistence /colonization and UTI is
|
bacterial binding via fimbriae
|
|
Factor favoring bacterial persistence/colonization and UTI despite high osmolarity and urea concentrations and low pH is
|
high bacterial growth rates
|
|
Host factor favoring bacterial persistence/colonization and UTI is
|
Urinary stasis
|
|
Host factor favoring bacterial persistence/colonization and UTI despite frequent voiding and high urinary flow is
|
Absence of bactericidal effects of secreted proteins
|
|
Pyogenic inflammation in complicated UTI due to Gram- negative bacteria is due to
|
Lipopolysaccharide (LPS)
|
|
Empiric DOC to treat community-acquired UTI in adults is
|
ciprofloxacin
|
|
The abx class that inhibits DNA gyrase or topoisomerase IV and blocks with bacterial DNA replication is
|
Fluoroquinolones
|
|
DOC to treat UTI in pregnant women is
|
Nitrofurantoin
|
|
Gram-positive bacteria that cause uncomplicated UTI in sexually active, young women are
|
Staphylococcus saprophyticus
|
|
Differentiation of Staphylococcus saprophyticus from S. epidermidis (both coagulase negative) is based on
|
novobiocin resistance
|
|
In elderly or pt with risks of urinary stasis, fever, chills, flank pain, and CVA tenderness; Lab: pyuria, casts, nitrite+. TOW?
|
Pyelonephritis due to E. coli
|
|
Pt hospitalized > 72 h for comorbidity has urinary frequency, dysuria and foul-smelling urine; w/ flank pain, fever and chills, in the presence of a urinary catheter:Clue: GNR; fermenter; encapsulated; intrinsic ampicillin resistance) Clue: GNR; slow fermenter; red pigment; intrinsic drug resistance) Clue: GNR; swarming growth [very motile]; slow fermenter; intrinsic drug resistance) Clue: GNR; non fermenter; oxidase+, blue pigment; intrinsic drug resistance) Clue: GPC in chains; catalase-neg; grows in high salt; penicillin resistance)
|
Klebsiella pneumoniae Serretia marcescens Proteus mirabilis Pseudomonas aeruginosa Enterococcus faecalis
|
|
If a patient with complicated UTI is severely ill or not improving with therapy, do what rapid test next?
|
renal ultrasound (to rule out urinary tract obstruction)
|
|
For a patient with complicated UTI, once culture and sensitivity available, switch to what?
|
Narrow-spectrum abx
|
|
2 or more of the following: fever (T>38°C) or hypothermia (T< 36°C), tachycardia (HR>90), tachypnea (RR>20), leukocytosis (WBC>12,000 or differential w/ >10% bands). TOW?
|
SIRS
|
|
SIRS + infection (e.g., positive blood culture) is
|
sepsis
|
|
Sepsis + organ failure, decreased perfusion (lactic acidosis, oliguria, altered mental status) or low BP. TOW?
|
Severe sepsis
|
|
Severe sepsis + hypotension despite fluids + lactic acidosis, oliguria, altered mental status.
|
Septic shock
|
|
Septic shock due to Gram-negative bacteria (e.g., E. coli, Klebsiella spp., or Pseudomonas aeruginosa) is
|
Endotoxic shock
|
|
Endotoxin that mounts pro-inflammatory cytokines, responsible for endotoxic shock, is
|
Lipid A of LPS
|
|
Genital chancre begins as a papule, ulcerates to form a single, painless, clean-based ulcer. TOW?
|
1o syphilis
|
|
Cause of genital chancre, begining as a papule, ulcerating to form a single, painless, clean-based ulcer.
|
Treponema pallidum
|
|
A pen-allergy, non-pregnant, female pt w/ fever, "copper penny" macular lesions on the palms or soles; RPR(+) should be
|
Doxycycline
|
|
Management choice of tabes dorsalis (10-20yrs), iritis, uveitis, or Argyll-Robertson pupils of pen-allergy in a pregnant woman w/ pen allergy; RPR(+) is
|
Desensitization
|
|
Hx of painful clustered vesicles with an erythematous base; urinary retention in a promiscuous woman. TOW?
|
HSV-2 >> 1
|
|
Giemsa stain of fluid from a herpetic lesion should reveal
|
Multinucleated giant cells
|
|
Patient with genital herpes does not respond to acyclovir because pt is infected with
|
thymidine kinase deficient HSV
|
|
A pregnant woman with 1o symptomatic HSV-2 infection is at risk of her baby developing
|
neonatal (congenital) herpes
|
|
Cause of painful genital ulcers; purulent, grey base; painful inguinal adenitis, in a man with multiple sexual partners is
|
Haemophilus ducreyi
|
|
Fastidious organism in the infiltrate of the penile ulcer, co- localized with neutrophils and fibrin, in a pt w/ chancroid is
|
Haemophilus ducreyi
|
|
All sex partners of pt with chancroid, regardless of symptoms, should be examined and treated with
|
Azythromycin > ceftriaxone
|
|
Most common cause of mucopurulent endocervical exudate (Gram stain non revealing) in a sexually promiscuous woman
|
Chlamydia trachomatis D-K
|
|
Dx of mucopurulent urethral discharge, dysuria, penile pruritis is based on
|
NAAT of urethral specimen or urine (+)
|
|
DOC of most frequent cause of nongonococcal urethritis
|
Azythromycin > doxycycline
|
|
Cause of rare genital ulcers, inguinal lymphadenopathy [cytology(-) for multi-nucleated giant cells; RPR (-)] in men is
|
Chlamydia trachomatis L1-L3
|
|
Hx of systemic Sx/Sn w/ cervical motion tenderness in a woman with turbo-ovarian abscess. TOW?
|
PID
|
|
Cause of mucopurulent urethritis, dysuria, penile pruritis [Smear (+):Gram-negative diplococci co-populated w/ PMNs] is
|
Neisseria gonorrhoeae
|
|
Deficiency in serum factors in a female pt w/ frequent gonorrhea and DGIs is
|
C6-C9
|
|
Immune evasion of Neisseria gonorrhoeae in frequent
|
Antigenic variation of pili.
|
|
Auxotrophic strains of N. gonorrhoeae with serum (complements) resistance are likely to cause
|
Septic arthritis (aka: DGI)
|
|
Most frequent complication of gonococcal (GC) infection in men
|
Epididymitis
|
|
Cause of "bull headed clap", urethral stricture, prostatitis is
|
Neisseria gonorrhoeae
|
|
Urethritis is treated with ceftriaxone + azythromycin
|
Concurrent GC + Chlamydia
|
|
An older woman with PID and tubo-ovarian abscess receives ceftriaxone, azythromycin, and metronidazole because
|
Polymicrobic (endogenous) infection
|
|
Cause of anogenital warts w/ histology (+): koilocytes is
|
HPV 6 and 11
|
|
Cause of atypical squamous cells of undetermined significance (ASCUS) on pap smear w/ no clinical signs of infection is
|
HPV 16 and 18
|
|
Cause of koilocytotic cells and possible progression to squamous cell carcinoma
|
HPV 16 and 18
|
|
Next step to identify viral cause of ASCUS on pap smear w/ and further management in a woman of age > 29 years is
|
Colposcopy > HPV DNA in bpsy
|
|
Wet prep of vaginal discharge from a pt w/ vaginal pruritis; ectocervical erythema ("strawberry cervix") should reveal
|
motile tissue flagellate
|
|
Gram stain of vaginal discharge w/ fishy odor from a pt w/ vaginal pruritis but no erythema and normal cervix should reveal
|
SECs stippled with Gram- variable organisms.
|
|
Pathology of bacterial vagisnosis is overgrowth (in vagina) of anaerobic Mobiluncus species and
|
Gardnerella vaginalis
|
|
DOC of bacterial vaginosis is
|
metronidazole
|
|
Wet prep of curdy discharge (no odor), adhering to vaginal walls, from a pregnant woman w/ recent UTI, who now has severe vaginal pruritis; vulvovaginal area - erythematous should reveal
|
budding yeasts with pseudohyphae
|
|
Normal commensal of skin, GI & GU tracts; endogenous overgrowth of budding yeast, capable of >10 diseases. TOW?
|
Candida albicans
|
|
Mechanism of action of a po DOC of vulvovaginal candidiasis is
|
blocks C14α-lanosterol demethylase
|
|
Hx of flu-like illness, lymphadenopathy, maculopapular rash in a bisexual man. Lab: lymphopenia and transaminase elevations; monospot/all serology (-). TOW?
|
Acute retroviral syndrome
|
|
Time from infection (acquisition) to acute seroconversiondetected by HIV serology (ELISA/W Blot) is
|
6-12 weeks.
|
|
Hx of mononucleosis-like illness and lymphadenopathy in a man who has sex man. Serology (-). What is HIV viral load?
|
>10,000 copies/ml
|
|
Host-cell receptor for HIV-1 infection
|
CD4
|
|
Homozygous for deletions in what gene renders resistance to infection and some protection against progression.
|
CCR5
|
|
Host cells that trap HIV and mediate the efficient transinfection of CD4+ T cells are
|
Dendritic cells
|
|
A man, who practices “sex with another man”, has antibodies to HIV (ELISA and WB) but asymptomatic. TOW?
|
Clinical latency
|
|
What happens to HIV-1 virus when acute retroviral syndrome progresses to clinical latency?
|
Virus continues to replicate low level.
|
|
A man who practices “sex with another man”, is now HIV-1 serology (+) and has dual symptomatic infections/cancer (any two from below). Expected CD4+ count is
|
CD4+ < 200/μL
|
|
A man with HIV infection has chronic diarrhea, oral thrush + toxoplasma encephalitis. Most likely CD4+ count is
|
< 50 cells/μL.
|
|
Most common cause of HIV- associated peripheral skin or mucosal ulcers
|
HSV-1 (>> Histo > CMV > VZV > Syphilis)
|
|
Most common cause of HIV- associated nodules
|
HHV-8 (aka KSHV)
|
|
Hx of fatigue, nausea, abdominal pain, diarrhea, fever, chills, night sweats, dry persistent cough w/ SOB and weight loss in a man with AIDS. Lab: PPD (-); blood culture (+) for AFB. TOW?
|
Mycobacterium avium- intracellulare (MAI) complex (aka: MAC)
|
|
Common cause of retinitis, viral pneumonitis or esophagitis in AIDS
|
CMV
|
|
Cases of CMV disease occur with immunosuppression level
|
CD4< 50
|
|
cytopathology of CMV infected tissue is characterized by large cells with
|
nuclear (Cowdry owl’s eye) and cytoplasmic inclusions
|
|
Hx of progressive CNS dz in a pt w/ AIDS: hemiparesis, visual, ataxia, aphasia, cranial nerves, sensory. Head MRI: ring- enhancing lesions. Toxo antibody (-). TOW?
|
JC virus
|
|
Definitive indication for initial HAART is CD4+ count?
|
350/mm3.
|
|
Objective of ARV Tx is to reduce viremia to what level of genomic RNA/mL
|
< 50 copies RNA/mL.
|
|
Initial regimen of anti-retroviral therapy is
|
Emtricitabine + Tenofovir + Efavirenz
|
|
Abacavir, emtricitabine, lamivudine, zidovudine, tenofovir belong to what class of antiretrovirals?
|
NRTIs
|
|
Efavirenz, nevirapine belong to what class of antiretrovirals?
|
NNRTIs
|
|
Atazanavir, Lopinavir, Saquinavir belong to what class of antiretrovirals?
|
Protease inhibitors
|
|
This drug binds to gp41 and prevents conformational change required for viral fusion and entry into cells.
|
enfuvirtide
|
|
This drug inhibits integrase, responsible for insertion of HIV proviral DNA into the host genome.
|
raltegravir
|
|
A man has AIDS and CD4 <200cells/μL or thrush. Antibacterial prophylaxis needed besides HAART is
|
TMP-SMX (for PCP)
|
|
A man has AIDS and CD4 <100 + pos toxo IgG. Chemoprophylaxis needed besides HAART is
|
TMP-SMX (for Toxoplasma encephalitis)
|
|
A man has AIDS and CD4 <100 + PPD >5mm induration. Antibacterial prophylaxis needed besides HAART is
|
INH + pyridoxine
|
|
A man has AIDS and CD4 <50. Antibacterial prophylaxis needed besides HAART is
|
azithromycin (for MAC)
|
|
Hx of fever, a pustule at a cat scratch site, adenopathy, hepatosplenomegaly in a pt w/ AIDS. Warthin-Starry stain tissue (+). TOW (clue: bacillary angiomatosis)?
|
Bartonella henselae
|
|
Leading causes of congenital infections are
|
ToRCH3eS-List; Toxoplasma gondii, Rubella, CMV, HSV/HBV/HIV, Syphillis. Listeria
|
|
disease in a neonate (mom at pregnancy had mono-like illness after eating undercooked beef or pork or exposure to oöcysts in cat feces) is
|
Toxoplasma gondii
|
|
Drug for pregnant woman in first trimester to prevent transmission if mother seroconverts is
|
Spiramycin
|
|
Hx of deafness, cataracts, heart defects, or microcephaly in a child (of a seronegative, caregiver mom, exposed to “Blueberry muffin baby” in 1st trimester). TOW?
|
congenital rubella syndrome (CRS)
|
|
Dx of CRS usually with positive anti-rubella antibody type?
|
IgM
|
|
Microcephaly, seizures, sensorineural hearing loss, feeding difficulties, petechial rash, hepatosplenomegaly, or jaundice in a neonate. PCR of any body fluid should yield
|
CMV
|
|
After primary infection, CMV, characterized as enveloped dsDNA betaherpesvirus; establishes
|
lifelong latency
|
|
Hepatosplenomegaly, neurologic abnormalities, frequent infections in a neonate w/ low CD4+ counts. Woman before birthing should have received
|
Nevirapine
|
|
Cause of vesicular skin lesions + conjunctivitis in a child (asymptomatic at birth)
|
HSV-2
|
|
Hx of cutaneous lesions, hepatosplenomegaly, jaundice, saddle nose, and saber shins. Hutchinson teeth, + CN VIII deafness in a neonate (mom is a prostitute). TOW?
|
3o syphilis
|
|
Neonatal septicemia or meningitis (mom had flu-like Sx and ate imported cheese during pregnancy). TOW?
|
Listeria monocytogenes
|
|
Skin (rashes), Soft Tissue, & Musculoskeletal Infections (also Sepsis)
|
Measles
|
|
What are the SIX red rashes of childhood (acute, febrile exanthema illnesses)? (Clue1: maculopapular rash; off-white lesions on buccal mucosa, MMRV vaccine prevents) (Clue2: maculopapular rash starting on face moving to foot; MMRV prevents) (Clue3: scarlatina rash post pharyngitis) (Clue4: vesicular rash, moderate pain) (Clue5: maculopapular “slapped face” appearance in a young child) (Clue6: maculopapular rash and systemic Dz in immunocompromised pt)
|
Rubella Scarlet fever (GAS) Chicken pox (VZV) Parvovirus B19 HHV-6
|
|
Worldwide rubella infection, with only human reservoirs known this infectious agent is a
|
RNA togavirus
|
|
>95% seropositive after MMRV if >12mos age and lifelong protection against rubella is conferred with?
|
Single dose
|
|
Cause of single or multiple scaly and/or crusted patches and/or plaques, affecting the scalp or beard area +/- inflammation.
|
Dermatophytes
|
|
KOH prep of scales from the scalp and plucked hairs from cutaneous mycoses may reveal?
|
hyphae and spores
|
|
Most common cause of cutaneous mycoses
|
Trichophyton spp.
|
|
Common cause of cutaneous mycosis with animal contact
|
Microsporum spp.
|
|
Oral DOC of cutaneous mycoses
|
itraconazole
|
|
Topical DOC of cutaneous mycoses
|
terbinafine
|
|
Dz w/ subcutaenous lesions w/ slow spread by lymphatic system producing nodules in garnders or from rose thorns
|
Sporotrichosis
|
|
Cause of subcutaenous lesions w/ slow spread by lymphatic in gardner from rose thorns
|
Sporothrix schenckii
|
|
Dimorphic fungus that grows at 37°C as cigar-shaped yeast, and produces septate hyphae and conidia (in daisy arrangement) at 25°C is
|
Sporothrix schenckii
|
|
DOC of sporotrchosis
|
itraconazole.
|
|
Cause of deeper and wider lesions with interconnecting subcutaneous abscesses arising from infection of several neighboring hair follicles, in young children.
|
Staphylococcus aureus (carbuncle)
|
|
Cause of superficial pustules progressing to erosions covered by honey-colored crusts, surrounded by erythematous halo, in young children.
|
Staphylococcus aureus >> Streptococcus pyogenes (non- bullous impetigo)
|
|
Dz characterized by bullae and denuded areas after the blisters rupture, covered by thin, varnish-like light brown crusts; regional lymphadenopathy, in children.
|
Bullous impetigo
|
|
DOC if lab: gram stain and culture of pus or base of the lesions yields GPC in chains. DOC if lab: gram stain and culture of pus or base of the lesions yields GPC in clusters.
|
Penicillin G Nafcillin
|
|
mecA (SCC) genes which encode PBP2a, w/ low affinity for β-lactams; confers resistance in Staphylococcus aureus against what?
|
Nafcillin
|
|
Cause of spreading (butterfly-wing) erythema on the face that responds to empirical penicillin.
|
Streptococcus pyogenes (Erysipelas)
|
|
Cause of severe pain on his knee w/ site of injury is tender and erythematous. Blood culture may yield?
|
Streptococcus pyogenes. (Cellulitis)
|
|
What is the microbial factor that promotes degradation of C3b by binding to factor H, the serum β globulin factor
|
M protein
|
|
Other epidemiologically linked or risk-associated causes of cellulitis are: Clue1: cat/dog bite. What? Clue2: Salt water exposure. What? Clue3: Fresh water exposure. What? Clue4: Neutropenia. What? Clue5: Human bite. What?
|
Pasteurella multocida / Capnocytophaga canimorous Vibrio vulnificus Aeromonas hydrophila Pseudomonas aeruginosa Eikenella corrodens
|
|
Most likely cause of fever/chills/ night sweats, localizing pain/tenderness or swelling/erythema (lab: ↑ESR, ↑CRP; ↑WBC w/ left shift. Radiology: periosteal elevation.) is
|
Staphylococcus aureus (Osteomyelitis)
|
|
Major antiphagocytic virulence factor of drug-resistant organism that causes osteomyelitis is
|
protein A
|
|
Major neutrophil-damaging virulence factor of drug- resistant organism that causes osteomyelitis is
|
Penton-Valentine leukocydin
|
|
Cause of vertebral, sternoclavicular or pelvic bone infections (in pt w/ IVDU) or osteochondritis of foot (following penetrating injuries through tennis shoes)?
|
Pseudomonas aeruginosa
|
|
Cause of osteomyelitis in pt w/ underlying sickle cell Dz; blood culture +)?
|
Salmonella typhimurium
|
|
Cause of chronic, vertebral osteomyelitis (blood culture negative)?
|
Mycobacterium tuberculosis
|
|
Cause of osteomyelitis in pt. w/ hx of cat bites; GNSR; fastidious growth of wound culture?
|
Pasteurella multocida
|
|
Cause of fever, chills, malaise, joint pain, swelling. PE: tenderness, erythema, heat, swelling, decreased ROM. CBC: leukocytosis w/ neutrophils predominating; joint aspirate: no crystals. Clue1: sexually active; BLCx (-); responds to ceftriaxone Think of other pathogens (BLCx negative): Clue2: Rheumatoid arthritis? Clue3: IVDU Clue4: Unpasteurized dairy products Clue5: Diabetes
|
Septic arthritis. Neisseria gonorrhoeae S. aureus S. aureus, P. aeruginosa Brucella spp. S. agalactiae (GBS)
|
|
Dz is characterized by arthritis in up to 6 joints (especially knees, feet), low back pain/stiffness, irritable eyes w/ or w/o redness, conjunctivitis, iritis, malaise. TOW?
|
Reactive arthritis (C. trachomatis, N. gonorrhoeae Campylobacter, Salmonella)
|
|
Cause of bacteremia in neutopenic pts with central line or pts with prosthetic devices and catheters; blood culture (+)
|
Staphylococcus epidermidis
|
|
Cause of intraabdominal abscess w/ putrid pus; anaerobic bacteremia in pt with trauma or solid GI tumor?
|
Bacteroides fragilis.
|
|
A woman with obstetric infection has fever > 102oF, SBP < 90; diffuse sunburn-like rash or desquamation of palms and soles; multisystem Sx/Sns; vomiting, and diarrhea; BLCx (-). TOW?
|
Staphylococcal Toxic shock Syndrome
|
|
What is the toxin associated with staphylococcal toxic shock syndrome?
|
TSST-1 (a superantigen)
|
|
Cause of severe, watery diarrhea in a woman with toxic shock syndrome?
|
Enterotoxin (coregulated with TSST-1)
|
|
Cause of toxic shock syndrome, which responds to vancomycin and clindamycin?
|
MRSA
|
|
Hx of fever > 38.9oC, SBP < 90 ; diffuse sunburn-like rash or desquamation of palms and soles, in a man w/ necrotizing fasciitis or myositis; multisystem involvement; BLCx (+). TOW?
|
Streptococcal toxic shock syndrome
|
|
What is the toxin associated with streptococcal toxic shock syndrome?
|
SpeA (superantigen)
|
|
DOC for streptococcal toxic shock syndrome
|
PenG + clindamycin
|
|
Hx of fever, chills, and hypotension. Blood culture yields a GNR, oxidase (-), lactose fermenting organism on MacConkey agar. Immunological mediators of sepsis.
|
IL-1 and TNF
|
|
DOC for a neutropenic pt w/ line-associated infection w/ immune suppression (hematologic malignancy, organ or hematopoietic stem cell transplantation, chemotherapy); w/ positive blood cultures and β-D-glucan antigenemia?
|
Caspofungin
|
|
DOC for a line-associated infection in a pt w/ GI tumor; lab: positive blood cultures and β-D-glucan antigenemia?
|
Fluconazole
|
|
Without prophylaxis with valganciclovir, D+/R- solid organ txp patient will develop
|
CMV disease
|
|
Cause of mononucleosis-like dz with fever, myalgia/ arthralgia w/ lab: leukopenia, LFT abnls, in a pt w/ solid organ transplant?
|
CMV
|
|
Lung biopsy reveals large cells with nuclear inclusions (Cowdry owl's eyes inclusion bodies) in a pt with AIDS and interstitial pneumonia. TOW?
|
CMV
|
|
DOC for CMV antigenemia in a febrile pt with solid organ tansplant?
|
valganciclovir
|
|
Cause of hematuria, hemorrhagic cystitis, or ureteric stenosis, or interstitial nephritis in a severly immunocompromised pt?
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BK virus
|
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What is the most common cause of bacteremia associated w/ foreign device (prostheses, intravenous cathether, or central lines) in co-morbid, hospitalized pts?
|
Staphylococcus epidermidis
|
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What is the cause of infections associated w/ ventilator support of respiration in co-morbid pts in the ICU?
|
Pseudomonas aeruginosa
|
|
DOC for a pt w/ travel hx (back from the tropics), who has flu-like symptoms; splenomegaly; lab: CBC: anemia, thrombocytopenia, hypoglycemia. Blood smear: enlarged RBCs and Schuffner dots.
|
mefloquine + primaquine
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Which drug is contraindicated in specific Tx of liver form of malaria in pts w/ G6PD deficiency?
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Primaquine
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DOC for a pt w/ travel hx (back from the tropics), who has flu-like symptoms (fever > 103oF), seizure, hyperparasitemia (>2.5% of RBC), pulmonary edema, or renal failure, or severe anemia?
|
Quinidine and doxycycline.
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Cause of malaria-like illness in an immunosuppressed pt w/o travel hx; lab: blood smear has cross-over rings in the RBCs?
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Babesia spp.
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|
A pt from S. America has a week-long fever, anorexia, lymphadenopathy, mild hepatosplenomegaly, and myocarditis; a nodular lesion on the arm. Blood smear should reveal motile species of what?
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Trypanosoma cruzi
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Cause of a chronic-stage systemic dz w/ cardiomyopathy, megacolon
|
Trypanosoma cruzi
|
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Cause of protracted fever and Crohn’s, celiac dz, ocular problems, and lymphadenopathy; duodenal biopsy demonstrating foamy macrophages in lamina propria?
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Tropheryma whipplei
|
|
Clinical Dx of painless papule (on arms, face, or chest), then vesicles/bullae, then black eschar + edema evolving over 3-5d associated with animal exposure is
|
Cutaeneous anthrax
|
|
Cutaneous anthrax can be treated in 7-10 days with
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Ciprofloxacin
|
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Animal exposure or biowarfare-associated fever, chills, sweats, GI sx, cough, malaise, chest pain, but no coryza (first 3-4d); then sepsis; CXR: wide mediastinum and bloody pleural effusion. Blood culture should yield
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Bacillus anthracis
|
|
Inhalation anthrax is treated with
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Fluoroquinolone > doxycycline
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Need to treat inhalation anthrax 60-100 days because
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Spores persist in vivo 30 days
|
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PxPr to prevent inhalation anthrax via aerosolized spores from powder particle size < 10 microns requires
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Cipro for 60 days
|
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Species of Clostridium that causes afebrile, systemic toxic diseases in infants (honey), and in adults foodborne (meat, canned vegetables), wound (injected), iatrogenic (cosmetic) is
|
C. botulinum
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Many pts w/ flaccid paralysis; unusual Clostrium botulium types (not A, B or E), common geography without common food source are clues to
|
bioterrorism
|
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Aerobic small slender gram-negative rod, erroneously identified as Pseudomonas sp., which causes glanders in horses and rarely humans; may be used in bioterrorism is
|
Burkholderia mallei
|
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Small, pleomorphic, aerobic Gram-neg rod that causes pathophysiology: 1) bite/abrasion (acquired from tick exposure or contact with rabbits) → nodule/ulcer → node → sepsis, or 2) inhalation (bioterrorism) → acute fever, dry cough. CXR: infiltrates + hilar adenopathy, is
|
Francisella turlarensis
|
|
Hx of acute fever, myalgias, remorrhagic rash, conjunctivitis, pharyngitis, headache, diarrhea, and thrombocytopenia in bioterrorism indicates
|
Viral hemorrhagic fever (e.g., Marburg, Ebola)
|
|
Aerobic, Gram-neg bipolar rod, which causes pathophysiology of (a) painful lymphadenitis, fever, chills, headache (after exposure to rodents, rabbits or fleas) (b) sepsis;(c) pneumonic (post bubo or epidemic): severe, often with hemoptysis and dyspnea, is
|
Yersinia pestis
|
|
Hx of sudden fever ≥ 39°C , homogeneous vesiculo- pustular rash (unlike common viral exanthems) in multiple pts is caused by
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Variolla major virus (small pox)
|
|
Hx: fever, headache, neck stiffness, and altered mental status; Kernig's/Brudzinski's sign other focal neurologic findings, rash, headache, seizures + myalgia; CSF: WBC > 2000 or PMNs > 1200; glucose < 34, protein > 220
|
Acute bacterial meningitis (ABM)
|
|
CSF gram stain of the most likely pathogen of ABM in a 6 mos-6yr old (or adults > 50 years) should reveal
|
Gram-positive diplococci
|
|
CSF gram stain of the most likely pathogen of ABM in an older child or young adult should reveal
|
Gram-negative diplococci
|
|
Most common cause of sepsis/meningitis in newborns/neonates?
|
Streptococcus agalactiae
|
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Cause of fever, headache, photophobia, nausea/vomiting, rash, diarrhea, meningeal signs, in older children in the summer months; CSF with 10-<1,000 WBC typical, mostly monos, moderately elevated protein?
|
Aseptic meningitis caused by enteroviruses
|
|
Cause of aseptic meningitis in men with exposure to rodents?
|
Leptospira interrogans
|
|
Cause of aseptic meningitis with hx of tick bite and erythema migrans?
|
Borrelia burgdorferi
|
|
Cause of aseptic meningitis with hx of sex with multiple partners; CSF PCR(+)?
|
HSV-2 > 1
|
|
Cause of fever, headache, photophobia, meningismus, in pts w/ solid organ transplant, malignancy, corticosteroid use. CSF glucose < 2/3 serum glucose, elevated protein, WBC > 5 with PMNs?
|
Listeria monocyotgenes
|
|
How does Listeria monocytogenes differ from other β- hemolytic bacteria?
|
Gram-positive rods; tumbling motility
|
|
Cause of chronic meningoencephalitis in a pt, who uses infliximab or native from endemic region; PE: papilledema. CXR (+). Lab: elevated monocytes on differential, low CSF glucose?
|
Mycobacterium tuberculosis
|
|
Test to confirm subacute mengoencephalitis in a, immunocompromised pt (CD4 <100); vesicular skin lesions [CSF profile: protein 30-150mg/dl, monos 10-100]?
|
CSF India ink
|
|
Cause of meningoencephalitis after a hx of respiratory illness after travel to SW USA?
|
Coccidioides immitis
|
|
Test to confirm CNS pathology with fever, cognitive deficits, focal neurologic signs, seizures; temporal lobe involvement on MRI. Lab: no papilledema, CT (no brain lesion)?
|
CSF PCR (+)
|
|
Cause of fever, cognitive deficits, focal neurologic signs, seizures, abnormal mental status with ataxia, hemi-paresis, in a pt w/ AIDS?
|
JC virus > HHV-6
|
|
Cause of fever, cognitive deficits, focal neurologic signs, seizures or abnormal mental status with ataxia in an adult during outdoor activity?
|
West-Nile virus > SLE
|
|
Hx of fever, cognitive deficits, focal neurologic signs, seizures, in a pt w/ AIDS (CD4 < 50). MRI: multifocal (ring- enhancing) lesions in basal ganglia. Rule out?
|
Toxoplasma encephalitis (TE)
|
|
HIV-infected Pt with TE should receive (for life)
|
pyrimethamine + leucovorin + sulfadiazine
|
|
Folinic acid (leucovorin) prevents bone marrow suppressive effect of
|
pyrimethamine.
|
|
Cause of confusion, stiff neck, irritability over wks to months, in immunocompromised pts; CT/MRI = multifocal lesions in midbrain, brain stem, & cerebellum; wet mount CSF = motile macrophage-like organisms
|
Acanthamoeba spp. (GAE)
|
|
Cause of severe headache and other meningeal signs, fever, vomiting, and focal neurologic deficits, frequently progressing to coma, in a healthy boy (summer diving activity)?
|
Naegleria fowleri (PAM)
|
|
Cause of seizures, chronic headache, symptomatic hydrocephalus, in immigrants; pt. successfully responds to praziquantel + anti-convulsant drug?
|
Taenia solium (neurocysticercosis)
|
|
Pt from Africa had fever, lymphadenopathy, chancre, and pruritus weeks ago; now has headaches, somnolence, neuro Sns; slowly responds to pentamidine isothionate or suramin. TOW?
|
Sleeping sickness caused by Trypanosoma brucei
|
|
Hx of rigidity, muscle spasm, and autonomic dysfunction. Trismus due to masseter spasm in an infant w/ umbilical stump infection. Neurotoxin interferes w/
|
GABA and glycine
|
|
Hx of afebrile illness w/ diplopia, dysarthria, dysphoria, dysphagia, in a pt w/ IDU skin poppers with black tar heroin. Neurotoxin blocks the release of
|
Acetylcholine
|
|
Immediate treatment of a male infant w/ constipation, a weak cry, and drooling, hypotonea and cranial neuropathy, after ingestion of home-processed honey.
|
Equine immune globulin (infant botulism)
|
|
Ingestion of a raw potato delivers a new vaccine protein to elicit an immune response. The immune structure to interact with the vaccine protein?
|
Lamina propria mucosae
|
|
Inflammation and the resulting increase in vascular permeability permit leakage into damaged or infected sites are effected by
|
Phagocytic cells and acute phase proteins
|
|
The serum of a pt, who has IgG and IgM deficiency, appears to fix complement in an assay for tetanus antibodies. What is the explanation?
|
Activation of the alternate pathway
|
|
A 3-year-old boy with genetic C3 deficiency has recurrent ear and lung infections due to pyogenic bacteria. Deficiency of what?
|
B lymphocytes
|
|
A very young child, w/ recurrent infections due to Staphylococcus aureus, now has numerous granulomas. TOW?
|
Chronic granulomatous dz
|
|
Treatment with which protease enzyme causes decrease in avidity of IgG w/o changing the specificity of the antibody?
|
Papain
|
|
Cells activated by both γ-IFN and CD40 are
|
Macrophages
|
|
High-dose chemo has caused severe bone marrow suppression in a pt with hematologic malignancy. Reversal is plausible with what?
|
GCSF
|
|
Function of the T-lymphocyte receptor (CD3) complex of transmembrane proteins?
|
Signal transduction
|
|
The MHC class I pathway presents an antigen directly to what?
|
CD8+ T lymphocytes
|
|
HSV infection can block the transfer of antigenic peptides from the cytoplasm to the ER of the infected cells. As a result of this, action of what cell type is compromised?
|
CD8+ T cells
|
|
Infection of the thyroid gland can induce the expression of MHC II molecules. Which cell types would initiate an autoimmune response, leading to Hashimoto’s thyroiditis?
|
CD4+ T cells.
|
|
PPD skin test (+) in a pt , who was vaccinated against turberculosis in his native country, reflects response of what cell type?
|
CD4+ T lymphocytes (Th1 response → γ-IFN)
|
|
A man with hx of MI is given a morphine injection for a new episode of chest pain; 10 mins later, he has itching and urticaria. Mechanism of this reaction?
|
mediators from sensitized mast cells
|
|
Loss of skin pigments, sense of touch, inability to feel objects and pain in a pt from Africa, whose skin scraping contains AFBs, is caused by
|
Th1-mediated DTH reactions
|
|
A man with polycystic kidney dz, who receives a renal transplant and cyclosporine, develops a high temp and swelling and tenderness in the grafted kidney. TOW?
|
Immunity to the donor MHC antigens.
|
|
A man who now has progressive stupor and laryngeal spasms for 3 days after pt was being attacked by a wild bat in a cave a month ago should have received
|
Inactivated rabies virus vaccine
|
|
Alternative and lectin pathways of complements activated
|
bacterial surfaces
|
|
Classic complement pathway is activated by antibody- antigen complexes involving antibody class type
|
IgM >> IgG
|
|
Chemotactic and anaphylotoxic complements are
|
C3a, C5a
|
|
successful opsonization of all non-encapsulated bacteria are by complement
|
C3b
|
|
Defect or deficiency of which complements predisposes individuals to infections caused by Neisseria spp., the causative agents of gonorrhea and meningitis
|
C6-C9
|
|
Antimicrobial (immune) response important for intracellular bacterial infections involves cell type
|
Th1 CD4 T cells
|
|
Immune response important for viral infections involves cell type
|
CD8 cytolytic T cells
|
|
Major antibody in secretions and plays a significant role in first-line defense at the mucosal level is
|
IgA
|
|
Main antibody in the initial “primary” immune response and allows good complement activation is
|
IgM
|
|
Fc region of this immunoglobulin binds to eosinophils, basophils and mast cells and is significant mediator of allergic (hypersensitivity) reactions
|
IgE
|
|
What on macrophages enables them to sense that the material is microbial in origin, and must therefore be eliminated quickly?
|
Toll-like receptor
|
|
These oxygen-dependent enzymes: NADPH oxidase, superoxide dismutase, and myeloperoxidase are involved in killing of what?
|
Gram-positive bacteria
|
|
These oxygen-independent enzymes/proteins: lysosome, lactoferrin, defensins and other cationic proteins are involved in killing of what?
|
Gram-negative bacteria
|
|
Infections persist, because mφ activation is defective, leading to chronic stimulation of CD4+ T cells in what dz?
|
Chronic granulomatous Dz
|
|
Defective respiratory burst, predisposing chronic bacterial infection is associated with deficiency of what?
|
Glucose-6-phosphate dehydrogenase (G6PD)
|
|
All nucleated cells express MHC I antigens
|
HLA-A, B, C
|
|
Antigen-presenting cells express MHC II antigens
|
HLA-DP, DQ, DR
|
|
Lymphocyte proliferation (T, B) and NK → cytotoxicity are undertaken by what cytokine?
|
IL-2
|
|
B-cell activation, IgE and IgG4 switch, ↓ TH1 cells/ Mφ, ↓ IFN-γ, TH0 → TH2 are all undertaken by what cytokine?
|
IL-4
|
|
Mφ activation; elevated expression of MHC and FcRs molecules on B cells, IgG2 class switching, increased IL-4 and TH2 are all undertaken by what cytokine?
|
IFNγ
|
|
The Th1 response, driven primarily by IFN-γ leads to the activation of
|
macrophages
|
|
The Th2 response, driven primarily by IL-4 and IL-5, leads to the production of IgE and IgG4 and to the activation of
|
mast cells and eosinophils.
|
|
Variable T and B cells in DiGeroge’s syndrome is associated with
|
Thymic aplasia
|
|
No B cells and immunoglobulins in X-linked agammaglobulinemia (Bruton’s) is associated with
|
Loss of Btk tyrosine kinase
|
|
Lack of anti-polysaccharide antibody and impaired T-cell activation causing Wiskott-Aldrich syndrome is associated with
|
X-linked-defective WASP gene
|
|
Inability to control B cell growth in X-linked lympho- proliferative syndrome is associated with
|
SH2D1A mutant
|
|
Glomerulonephritis, pulmonary hemorrhage in Goodpasture’s syndrome is caused by what autoantigen?
|
basement membrane collagen type IV
|
|
Hyperthyroidism in Grave’s Dz is caused by what autoantigen?
|
Thyroid-stimulating hormone
|
|
Progressive muscle weakness in Myasthenia gravis is caused by what autoantigen?
|
Acetyl choline receptor
|
|
Brain degeneration, paralysis in Multiple sclerosis (MS) is caused by what autoantigen?
|
Myelin basic protein, proteolipid protein
|
|
Localized allergies (e.g., drug allergy, asthma, hay fever) and anaphylaxis (food, drug) w/ systemic inflammation throughout circulation are associated with reaction?
|
Type I hypersensitivity
|
|
Autoimmune hemolytic anemia: Ab’s produced vs RBC membrane Ag’s, mismatched blood (transfusion rxn), and allergies to antibiotics (e.g., penicillins, sulfa drugs) are associated with reaction?
|
Type II hypersensitivity
|
|
Grave’s Disease, Myasthenia Gravis, Goodpasture’s syndrome are all associated with reaction?
|
Type II hypersensitivity
|
|
Post-streptococcal glomerulonephritis, serum sickness to horse diphtheria anti-toxin, systemic lupus erythematosis (SLE), and rheumatoid arthritis are all associated with reaction?
|
Type III hypersensitivity
|
|
Poison ivy, erythematous induration in tuberculin skin test, and transplantation/graft rejection are all associated with reaction?
|
Type IV hypersensitivity
|