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(OMS2) GI II Exam 1 > DSA 3: Acute Infectious Diarrhea > Flashcards

DSA 3: Acute Infectious Diarrhea Flashcards

1
Q

what are the signs of mild dehydration?

A

thirst, dry mouth, decreased axillary sweat, decreased urine output, slight weight loss

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2
Q

what are the signs of moderate dehydration?

A

orthostatc fall in blood pressure, skin tenting, sunken eyes (infants: sunken fontanelle)

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3
Q

what are the signs of severe dehydration?

A

lethargy, obtundation, feeble pulse, hypotension, frank shock

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4
Q

if pt presents with fever >38.5 degrees, bloody stools, increased fecal WBC’s, immunocomprimised or is an elderly host, should you order stool microbiology studies?

A

yes

  • if no pathogen is found, empirical treatment and further evaluation
  • if pathogen found, select specific treatment
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5
Q

what are the indications for further evaluation?

A
  • profuse diarrhea (6+ stools/day)
  • hypotension and tachycardia
  • dysentery (bloody diarrhea with leukocytes)
  • fever >38.5
  • last longer than 48 hrs, no improvement
  • recent antibiotic use (check for C.Diff)
  • severe abdominal pain in pt >50
  • elderly pt >70 or immunocomp
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6
Q

what is the work-up for diarrhea?

A

CBC, electrolytes, BUN, Cr, blood culture

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7
Q

what is the cornerstone of diagnosis for diarrhea?

A

microbiologic analysis of the stool

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8
Q

what does a routine stool culture include?

A
  • salmonella
  • shigella
  • E. Coli
  • most detect campylobacter (but may need to request)

takes 24-48 hours for results

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9
Q

what stool bacterial cultures need to be asked for specifically?

A
  • Shiga-like toxin detection for 0157:H7 EHEC
  • Vibrio species
  • Yersinia
  • C. Diff
  • stool protozoal antigen (Giardia, Cryptosporidium, E. histolytica)
  • stool viral PCR antigen (rotovirus, norovirus)
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10
Q

what may be indicated if stool studies are unrevealing?

A

endoscopy

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11
Q

what can you identify on abdominal CT?

A

colitis

CT more sensitive than XR for free air

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12
Q

what can you ID on plain abd XR?

A

ileus or toxic megacolon

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13
Q

what are the common food poisoning pathogens found in chicken?

A

salmonella, campylobacter, shigella

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14
Q

what are the common food poisoning pathogens found in undercooked hamburger?

A

enterohemorrhagic E.coli (0157:H7)

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15
Q

what is the most common food poisoning pathogen found in fried rice?

A

bacillus cereus

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16
Q

what are the common food poisoning pathogens found in potato salad, mayo or cream pastries?

A

staph aureus

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17
Q

what is the common food poisoning pathogen found in eggs?

A

salmonella

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18
Q

what is the common food poisoning pathogen found in uncooked foods, lunch meat or soft cheeses?

A

listeria

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19
Q

what are the common food poisoning pathogens found in seafood?

A
  • Vibrio species (salmonella, acute HepA)
  • Norovirus
  • Campylobacter
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20
Q

gram positive cocci (grape clusters), preformed enterotoxins

  • N/V
  • **watery diarrhea
  • rapid onset w/in 6hrs of ingestion
  • rapid resolution w/in 24-48 hrs

risk factors: potato salad, mayo

A

Staph aureus

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21
Q

gram positive rod, preformed enterotoxins

  • watery diarrhea
  • rapid onset w/in 6 hrs
  • rapid resolution w/in 24-48 hrs

risk factors: fried rice!

A

Bacillus cereus

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22
Q

heat resistant gram positive, spore-forming rod

  • preformed enterotoxin
  • watery diarrhea (**NO fever or vomiting)
  • crampy abd pain
  • onset w/in 8-16 hrs of ingestion, need to ingest large quantities of org
  • rapid resolution w/in 24-48 hrs

risk factors: beef, ham, poultry, legumes, gravy

A

Clostridium perfringens

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23
Q

gram NEG rod, non-motile

  • enterotoxin shiga toxin
  • DYSENTERY begins as watery diarrhea -> intense colitis with fever and frequent small-volume stools w/blood and pus
  • fever for 3-4 days, typically lasts 7 days

risk factors: potato salad, lettuce, raw veggies

A

Shigella

GIVE ABX!

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24
Q

what are the dx and tx of shigella?

A
  • dx: (+) fecal leukocytes, (-) lactose on stool culture difficult to distinguish from IBD
  • tx: Bismuth, ampicillin, fluoroquinolone, or trimethoprim/sulfamethoxazole
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25
Q

what are the post-infectious complications of Shigella?

A

reactive arthritis, HUS

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26
Q

gram neg, NON-lactose fermenting, MOTILE, rod-shaped

  • orgs traverse intestinal epithelium through M cells overlying Peyer’s Patches
  • non-typhoidal
  • watery -> blood diarrhea
  • fever, abd camping, N/V
  • lasts 5-10 days, self limiting

risk factors: eggs, poultry, milk, exposure to reptiles (turtles)
- increased risk with immunocompromised/HIV, leukemia and Sickle Cell

A

Salmonella typhimurium

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27
Q

what is the dx needed for salmonella typhimurium?

A

stool culture

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28
Q

what are the complications of salmonella typhimurium infection?

A

septic arthritis, abscess, osteomyelitis

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29
Q

gram NEG rod, anaerobic

  • org’s penetrate thru Peyer’s Patches
  • can be asymptomatic carriers
  • Rose spots rash with fever
  • 7-14 days AFTER ingestion
  • 2 symptomatic phases separated by asymptomatic phase: febrile (103-104!)
  • **pea-soup green-yellow fowl smelling diarrhea -> bloody diarrhea

risk factors: poor sanitation, travel

A

Salmonella typhi

TYPHOID FEVER

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30
Q

what is the dx and tx of Salmonella typhi?

A
  • dx: stool culture, blood culture, fecal leukocyte (+)

- tx: hand-washing, vaccine, fluoroquinolones (becoming resistant)

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31
Q

gram NEG curved/spiral-shaped rod

  • oxidase (+), motile flagellum with “cork-screw” motion
  • watery -> bloody diarrhea
  • fever, malaise
  • crampy abd pain
  • erythema nodosum

risk factors: undercooked poultry, dairy, contaminated water

A

Campylobacter jejuni

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32
Q

what is the dx and tx of campylobacter jejuni?

A
  • dx: fecal leukocyte (+)
  • stool culture need Campy blood agar
  • tx: supportive, NO abx
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33
Q

what are the complications of campylobacter jejuni infection?

A

reactive arthritis, Guillan-Barre syndrome

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34
Q

gram NEG bacilli, anaerobic, curved-shaped with flagellum

  • toxin production
  • N/V/abd cramping
  • PROFUSE (1L/hr) watery diarrhea
  • mucous with epithelial cells = “rice water”
  • lasts 7 days

risk factors: waterborne illness (saltwater), raw seafood (oysters), poor sanitation in underdeveloped nations

A

Vibrio cholerae

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35
Q

what is the dx and tx of Vibrio cholerae?

A
  • dx: stool microscopy (motile, darting short curved gram neg rods), gram stain of stool specimen
  • tx: rehydration/electrolyte replacement

prevention: sanitation, vaccination

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36
Q

gram NEG bacilli, cytotoxin production

  • N/V/abd cramps
  • watery -> bloody diarrhea (colonic)
  • lasts 2-5 days

risk factors: seafood (shellfish, oysters, shrimp)

A

Vibrio parahemolyticus

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37
Q

what is the dx and tx of Vibrio parahemolyticus?

A
  • dx: fecal leukocyte (+), stool culture (special media needed)
  • tx: self-limited
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38
Q

gram NEG bacillus

  • vomiting. diarrhea, abd pain w/in 16 hrs of ingestion
  • open wound in the water: bullous skin lesions
  • can be life threatening in immunocompromised (esp cirrhosis and hemochromatosis pts)

risk factors: war, shallow, coastal salt water, oysters

A

Vibrio vulnificus

39
Q

gram NEG, non-spore forming, rod-shaped, facultative anaerobic bacteria, motile with flagellum
- two types of sx: cholera-like (watery diarhea), OR bloody mucoid stools

risk factors: fresh water environments, open wounds in water (foot and ankle most common), suspect in early necrotizing fasciitis

A

Aeromonas hydrophila

GIVE ABX

40
Q

what is the tx of Aeromonas hydrophila?

A

ampicillin

41
Q

what are risk factors for travelers diarrhea?

A
  • travel to developing countries

- H2 blocker/PPI use (decrease acid production, increasing pH)

42
Q

what is the most common pathogen for traveler’s diarrhea?

A

EnteroToxigenic E. coli (ETEC)

43
Q

gram NEG rod

  • N/V, occasional fever
  • watery diarrhea
  • sudden onset, 3-6 days duration

risk factors: children, elderly, travelers, ingesting contaminated food or water

A

ETEC

44
Q

what is the dx and tx of E. coli

A
  • dx: fecal leukocyte (-), must be dx clinically because stool cultures can’t differentiate between ETEC and commensal gut E.coli
  • tx: abx may reduce infection by 1-2 days (trimethoprim/sulfamethoxazole, doxycycline, ciprofloxacin)
  • bismuth may help
45
Q

gram NEG rod, produces shiga-like toxin

  • watery -> bloody diarrhea -> ischemic colitis
  • NO fever

risk factors: food-borne (undercooked hamburger), raw veggies, raw milk

A

EnteroHemorrhagic E. coli (EHEC)

46
Q

what is the dx and tx of EHEC?

A
  • dx: CBC- peripheral leukocytes (+), anemia, thrombocytopenia, fecal leukocytes (+), fecal lactoferrin (+), stool culture w/ shiga-like toxin
  • tx: supportive, rehydration, abx only in extreme cases
47
Q

what are complications of EHEC?

A

hemolytic uremic syndrome (kidney insuff, hemolytic anemia, thrombocytopenia

  • occurs 5-10 days into course
  • much more likely to happen in children OR if EHEC treated with abx
48
Q

what is another E. coli, that causes fever, abd pain, watery -> bloody diarrhea with leukocytes

A

EnteroInvasive E. coli (EIEC)

49
Q

gram NEG coccobacilli

  • bloody diarrhea
  • fever
  • N/V, abd pain w/ PHARYNGITIS
  • infection located in terminal ileum (R side abd pain), can mimic appendicitis or CroHn’s disease

risk factors: virulence affects iron metabolism -> iron-overload syndromes, cirrhosis, hemochromatosis

A

Yersinia enterocolitica

tx: supportive

50
Q

what are the dx and complications of Yersinia enterocolitica

A
  • dx: stool/blood cultures (special media), fecal leukocytes (+)
  • clinically indistinguishable from salmonella or shigella
  • complications: erythema nodosum, reactive arthritis, myocarditis, kidney dz
51
Q

gram + rod, can grow in cold

  • fever, **NON-bloody diarrhea
  • headache, N/V, non-specific malaise in pregnant women**
  • 2-3 days duration

risk factors: pregnancy, extremes of age, immunocomp, eating unpasteurized dairy or deli meats

A

Listeria monocytogenes

GIVE ABX

52
Q

what is the dx and tx of listeria?

A
  • dx: blood culture (doesn’t grow on stool culture)

- tx: ampicillin and trimethoprim/sulfamethoxazole

53
Q

gram + bacillus, not acid fast, typically affects white men in their 40-60’s

  • arthralgia
  • wt loss
  • malabsorption
  • chronic diarrhea
A

Whipple disease (Tropheryma whipplei)

54
Q

what is the dx, tx and prognosis of Whipple disease?

A
  • dx: endoscopy with duodenal biopsy, PAS-positive macrophages with characteristic bacillus
  • tx: Abx therapy that cross BBB to help w/CNS symptoms
  • if untreated, disease is FATAL
55
Q

anaerobic, gram + spore forming bacillus, cytotoxin producing

  • watery, fowl smelling diarrhea
  • abd pain
  • fever

risk factors: hospitalization or ill contact w/in past 2 months, ABX USE (esp clindamycin, cephalosporin, fluoroquinolones), PPI also risk factor

A

Clostridium difficile

56
Q

what are the dx, tx and complications of C. diff?

A
  • dx: STOOL ASSAY - PCR for toxin A and B, peripheral leukocyte (+), pseudomembranes on colonic mucosa (green or yellow color)
  • tx: wash hands with soap and water, metronidazole, vancomycin
  • comp: TOXIC MEGACOLON (50% mortality rate, needs aggressive tx
57
Q

what is the most common cause of acute diarrhea in children <2 years old?

A

Rotavirus, especially in the winter months

- double stranded RNA virus

58
Q
  • vomiting and watery diarrhea
  • sx begin w/in 72 hours, last 2-3 days but up to 5
  • fecal leukocyte (-), detected by viral culture or PCR
  • wagon-wheel appearance on electron microsopy
A

Rotavirus

59
Q

double stranded DNA virus

  • **FEVER (103-104), chills, myalgia, sore throat
  • watery diarrhea and vomiting
  • conjunctivits, pharyngitis (may see exudates)
  • prolonged course (10 days)
  • dx: viral culture
A

Adenovirus (serotypes 40 /41)

60
Q

small non-enveloped RNA virus

  • fecal-oral transmission, outbreaks via contaminated food, water in nursing homes, child care centers, CRUISE SHIPS
  • vomiting, watery diarrhea
  • sx w/in 24-48 hrs
  • last 3 days
  • fecal leukocyte (-), viral cultures unrevealing, NO workup necessary d/t rapid resolution
A

Norwalk virus

61
Q

double stranded linear DNA (Herpesvirus family)

  • primarily affects the immunocompromised with CD4 <200
  • fever, abd pain, bloody diarrhea
  • persists for several weeks
  • dx: endoscopy with biopsy of ulcerated lesions using specific stains
A

Cytomegalovirus

need CMV-specific stain

62
Q

what is the most common cause of dysentery in the world?

A

Entamoeba histolytica

63
Q

trophozoite

  • fever, bloody diarrhea, abd pain
  • can penetrate bowel into portal circulation -> liver abscesses
  • persists for days/weeks
  • dx: FLASK-SHAPED ULCER on histology, stool for ova & parasite, or stool antigen (PCR for DNA)
  • fecal leukocytes (+)

risk factors: crowded living conditions (fecal-oral)

A

Entamoeba histolytica

64
Q

what are the tx and complications of Entamoeba histolytica?

A
  • tx: eliminate the trophozoite

- comp: TOXIC MEGACOLON or PNEUMATOSIS COLI (air in bowel wall)

65
Q

PEAR/KITE-SHAPED protozoa, 4 flagella, 2 nuclei

  • interferes with fat absorption -> steatorrhea, flatulence, abd pain
  • watery malodorous diarrhea (steatorrhea)
  • lasts 14-28 days, common cause of persistent diarrhea
  • STOOL AG DETECTION: check stool for ova/parasites

risk factors: water (streams/lakes-camping!), cattle, dogs, rodents
- those with IgA def more susceptible

A

Giardia lamblia

tx: supportive, tinidazole or metronidazole

66
Q

oocyst with 4 motile sporozoites

  • nausea, malaise, abd cramping
  • watery diarrhea (large vol >20L/day)
  • self-limiting, resolved in 7-14 days
  • immunocompromised pt: can be life-threatening
  • dx: stool antigen detection or direct microscopy, modified acid-fast staining, direct fluorescent antibody (have to ask for it!)

risk factors: SWIMMING POOLS

A

Cryptosporidium parvum

NOTE: resistant to chlorine tx, give ANTIVIRALS to immunocompromised patients to increase CD4 count and boost immune system

67
Q

roundworm (nematode)

  • enter the body via BARE FEET
  • larvae travel to lungs -> cough -> then swallowed and pooped out
  • often asymptomatic, or can cause abd pain, vomiting, bloating, diarrhea, cough, SOB
  • dx: rhabditiform larvae and esosinophils in stool

risk of HYPERINFETION in immunocompromised pts

A

Strongyloides stercoralis

tx: anti-helmintic

68
Q

malaise, anorexia, nausea, low-grade fever

  • watery diarrhea
  • can last up to 21 days in immunocompetent
  • indefinite in immunosuppressed :(
  • dx: oocysts in stool sample

risk factors: FRUITS/VEGS imported from endemic areas, TRAVEL to endemic areas

A

Cyclospora cayetanensis

tx: trimethoprim/sulfamethoxazole (TMP/SMX)

69
Q

acute, NON-bloody/watery diarrhea

  • crampy abd pain
  • can last for weeks -> malabsorption and wt loss
  • severe diarrhea in immunosuppressed
  • dx: repeated stool examinations, duodenal biopsy, oocysts visualized wet mounts by microscopy, or acid-fast stain
A

Cystoisospora belli

tx: Bactrim DS (trimethoprim/sulfamethoxazole)

70
Q

hookworm/whipworm

  • soil-transmitted helminth
  • can get very long, causing bowel obstruction
A

Ascaris lumbricoides

71
Q

fish tapeworm (from raw/undercooked fish)

  • can grow to 30 feet!
  • abd symptoms
  • worm absorbs Vit B12, causing B12 deficiency -> pernicious anemia and neurological symptoms
A

Diphyllobothrium latum

72
Q

what is the 2nd most common cause of esophageal varices behind alcohol in Africa?

  • also most common cause of small portal vein branch obstructions
A

Schistosoma mansoni

tx: praziquantel

73
Q

trematode, from contaminated FRESHWATER SNAILS

  • bloody stools
  • bladder cancer
  • liver cysts
A

Schistosoma mansoni

tx: praziquantel

74
Q

pork tapeworm, from ingesting undercooked pork

  • mostly asymptomatic -> rare serious cases cause SEIZURES (cysticercosis)
  • muscle or eye disease
A

Taenia solium

75
Q 
beef tapeworm (suckers), from ingesting undercooked beef
- mostly asymptomatic
A

Taenia saginata

76
Q

tapeworm, from unsanitary sheep slaughter that dogs eat

  • fecal-oral transmission, poor sanitation
  • form CYSTS IN LIVER/LUNGS
  • looks like free-flowing “hydatid sand” on CT
A

Echinococcus granulosus

77
Q

pinworm that causes severe perianal itching

  • dx: transparent tape test
  • tx: mebemdazole
A

Enterobius vermicularis

prevent infection by washing hands thoroughly and frequently, cut fingernails, disinfecting doorknobs, toilet seats, furniture, etc

78
Q

what is the tx for NON-bloody stools?

A
  • hydration (PO or IV) 8-10 glasses clear fluids/day
  • maintain electrolyte balance
  • anti-motility agents may be used, but **NOT in pt with C. diff or EHEC
79
Q

what foods should pt with diarrhea avoid?

A

lactose and high fiber foods, fats, caffeine, and alcohol

80
Q

what two pathogens mentioned are NOT killed by alcohol hand sanitizer?

A

Norovirus and C. diff

- must wash hands with soap and water

81
Q

what vaccines exist for diarrhea-causing pathogens?

A
  • Rotavirus
  • S. typhi
  • V. cholera
  • Hep A
82
Q

when is antibiotic prophylaxis indicated for travelers?

A
  • if immunocomprimised, IBD, hemochromatosis, or gastric achlorhydra
  • or if traveling to high risk areas
  • probiotics may be helpful, but in general prophylactic antibiotics not usually recommended
83
Q

formerly known as Reiter’s syndrome

- arthritis, urethritis, and conjunctivitis

A

Reactive arthritis

84
Q

Reactive arthritis may accompany or follow infections by which 4 pathogens?

A
  • salmonella
  • campylobacter
  • shigella
  • yersinia
85
Q

autoimmune-type thyroiditis

  • pericarditis
  • glomerulonephritis
A

Yersiniosis

86
Q

what is the major complication of campylobacter jejuni infection?

A

Guillian-Barre syndrome

  • inflammatory demyelinating polyneuropathy, paresthesias in hands/feet
  • severe respiratory muscle weakness
  • absent or depressed DTR’s
87
Q

EHEC (shiga-like toxin) can lead to what?

A

HUS

  • most common cause of acute renal failure in children
  • microangiopathic hemolytic anemia, thrombocytopenia
88
Q

what is recognized as a complication of infectious diarrhea?

A

post-infectious IBS

89
Q

acute diarrhea can also be a major symptom of which systemic infections?

A

viral hepatitis, listeriosis, legionellosis, toxic shock syndrome

90
Q

which pathogens typically affect the small bowel?

A

vibrio chilerae, ETEC, Rotavirus, Norovirus, CMV, Adenovirus, Giardia, Cyclospora, Staph aureus, Bacilis cereus

= watery stools

91
Q

which pathogens typically affect the large bowel?

A

campylobacter, shigella, EHEC, C. diff, Vibrio parahaemolyticus, E. histolytica, Herpes

= bloody stools

92
Q

what is a common pathogen that affects those with IgA deficiency?

A

Giardia

93
Q

Pt with hemochromatosis are prone to which pathogens?

A
  • Vibrio species
  • Listeria
  • Yersinia

should avoid raw fish

94
Q

AIDs pt are prone to which opportunistic infections?

A
  • Mycobacterium species
  • CMV, Adenovirus, Herpes
  • Cryptosporidium, Cystiosospora belli, Microsporidia, Blastocystic hominis
  • Neisseria gonorrhea, Trep pallidum, Chlamydia

(OMS2) GI II Exam 1 (20 decks)

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