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G2F > Acute diarrhea--bacterial causes > Flashcards

Acute diarrhea--bacterial causes Flashcards

1
Q

diarrhea- definition

A
  • adult- >200 g/day
  • child- >20 g/kg/day
  • clinically- 3 or more loose/watery stools/day OR dec in consistency and inc in frequency of BM of individual
  • lose HCO3 and K!!
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2
Q

noninfectious causes

A
  • medications
  • food sweeteners (sorbitol)
  • food allergies
  • tube feeding
  • acute diverticulitis
  • Graft vs Host dz
  • ingestion of toxins
  • chronic illness!- IBD, endocrine dz, tumors
  • ischemic colitis!!
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3
Q

epidemiology

A
  • 2nd most common infectious cause of death worldwide
  • 90% of acute diarrhea is infectious- 75% is viral
  • 10%- caused by medications, toxic ingestions, ischemia, etc
  • dehydration = major cause of death!
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4
Q

most frequent causes of infection

A

Salmonella and Campylobacter

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5
Q

Acute infectious diarrhea- transmission

A
  • fecal-oral- ingestion of contaminated food/water
  • most mild, self-limited
  • endoscopy rarely needed- check for C diff, distinguish if infection vs IBD or ischemia
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6
Q

bacterial toxins, enterotoxin-producing bacteria

A

small-bowel hyper-secretion

  • water diarrhea
  • vomiting
  • minimal or no fever
  • after a few hrs after ingestion
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7
Q

entero-adherent pathogens

A

small-bowel hyper-secretion

  • less vomiting
  • greater abd cramping/bloating
  • higher fever
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8
Q

cytotoxin-producing and invasive microorganisms

A
  • high fever

- abd pain

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9
Q

5 high risk groups in US

A
  • travelers
  • immunodef
  • daycare workers/kids/their family members (shigella, giardia, cryptosporidium, rotavirus)
  • nursing homes, assisted living, hospitals
  • consumers of certain foods
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10
Q

discriminations from true diarrhea

A
  • pseudo-diarrhea- freq passage of small volumes of stool- accompanies IBS or proctitis
  • fecal incontinence- neuromuscular disorders
  • overflow diarrhea- elderly/nursing home pts
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11
Q

diarrhea- indications for evaluation

A
  • profuse diarrhea with dehydration
  • hypotension and tachycardia not responsive to volume repletion
  • dysentery
  • fever >101 (38.5)
  • duration >48 h
  • recent abx use
  • new community outbreaks
  • severe abd pain
  • elderly
  • immunocompromised
  • creatinine >1.5x
  • peripheral leukocytes > 15,000
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12
Q

work-up cornerstone of diagnosis

A
  • microbiologic analysis of stool

- if stool studies unrevealing- endoscopy may be indicated

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13
Q

routine stool culture includes?

A
  • Salmonella
  • Shigella
  • E coli- ask for Shiga toxin detection for 0157:H7 eHEC
  • campylobacter
  • takes 24-48 hrs for results
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14
Q

stool culture- need to ask specifically for?

A
  • C diff PCR/toxin
  • ova parasites
  • stool ag (parasites- giardia, cryptosporidium)
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15
Q

labs

A
  • stool culture
  • viral stool culture
  • fecal leukocytes
  • lactoferrin (enzyme found in leukocytes)
  • CBC/renal fxn (BMP)- hemolytic uremic syndrome
  • may need blood cultures
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16
Q

radiology

A
  • plain abd xray- detect intraperitoneal air, assess for ileus or toxic megacolon
  • abd CT- free air, colitis
  • endoscopy- C diff pseudomembranes
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17
Q

food poisoning- chicken

A

salmonella, campylobacter, shigella

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18
Q

food poisoning- undercooked hamburfer

A

-EHEC (O157:H7)

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19
Q

food poisoning- fried rice or other reheated food

A

-Bacillus cereus

20
Q

Food poisoning- potato salad, mayonnaise, cream pastries

A

-Staph aureus

21
Q

food poisoning- eggs

A

-Salmonella

22
Q

food poisoning- Lunch meat, soft cheeses

A

-Listeria

23
Q

food poisoning- seafood

A
  • Vibrio species, Salmonella, acute hep A

- Norwalk, campylobacter

24
Q

Staphylococcus Aureus

A
  • preformed enterotoxins!!
  • N/V
  • watery diarrhea!
  • rapid onset- within 6 hrs
  • rapid resolution- 24/48 hrs
  • eggs, potato salad, mayonnaise, cream pastries!!!
25
Q

Bacillus Cereus

A
  • preformed enterotoxins!!!
  • vomiting- main symptom
  • rapid onset- within 6 hrs
  • rapid resolution- 24-48 hrs
  • fried rice!!!
  • watery diarrhea
26
Q

Clostridium Perfringens

A
  • preformed enterotoxins!!
  • watery diarrhea
  • crampy abd pain
  • rapid onset- 8-16 hrs- need to ingest large quantity of organisms!!
  • rapid resolution
  • beef, ham, poultry, legumes, gravy- heat resistant spores inadequately cooked
27
Q

Shigella

A
  • toxin mediated- enterotoxin shiga toxin!!
  • only need to ingest 100 organisms
  • children!
  • potato or egg salad, lettuce, raw veggies
  • BLOODY diarrhea
  • fever- 3-4 days
  • fecal leukocytes +
  • stool culture- diff to distinguish from IBD; lactose neg
  • 1-2 wks duration
28
Q

Shigella- tx, complications

A
  • Bismuth, ampicillin, fluoroquinolone, or TMP/SMX
  • resp complaints and seizures
  • reactive arthritis!
29
Q

Salmonella typhimurium

A
  • gram-neg, non-lactose fermenting, motile, rod-shaped bacteria
  • most cases in US- non-typhoidal!!
  • BLOODY diarrhea
  • fever
  • self-limited- 5-10 days
  • eggs, poultry; exposure to reptiles (turtles)
  • inc risk with Sickle cell pts!
  • stool culture- lactose -, motile
30
Q

Salmonella typhimurium- complications, tx

A
  • abx usually not indicated

- septic arthritis, osteomyelitis!

31
Q

Salmonella typhi- sx, dx, tx

A
  • international travel; poor sanitation
  • feca-oral
  • lives only in humans- there can be “healthy” carriers
  • prevention- good food prep, hand washing, vaccine
  • Typhoid fever!- sustained febrile illness (103-104)- rash of flat rose-colored spots
  • stool/blood samples- test for Salmonella typhi, fecal leukocyte +
  • fluoroquinolones, ceftriaxone, azithromycin
32
Q

Campylobacter jejuni

A
  • BLOODY diarrhea
  • fecal leukocytes +
  • self limited- 7 days
  • stool culture- need Campy blood agar- spiral, oxidase +, motile with flagellum
  • poultry
  • wild birds
33
Q

Campylobacter jejuni- complications, Tx

A
  • Guillian-Barre syndrome!!

- supportive

34
Q

Vibrio cholerae

A
  • toxin production!
  • O1 and O139 variants
  • rice water diarrhea- profuse
  • gram stain- curved/comma shaped, anaerobic gram-neg bacilli with flagellum
  • waterborne illness (saltwater)!!
  • raw oysters (seafood)!!
  • undeveloped nations- poor sanitation
35
Q

Vibrio cholerae- dx, tx

A
  • stool- motile, darting short curved gram neg rods
  • tx- rehydration/electrolyte replacement
  • prevention- sanitation, vaccination
36
Q

Vibrio parahemolyticus

A
  • non-O1 and non-0139 variants
  • cytotoxin production!
  • bloody diarrhea!
  • fecal leukocyte +
  • lasts 2-5 days
  • seafood!!
37
Q

Vibrio Vulnificus

A
  • gram neg bacillus
  • coastal salt water!!
  • eating raw shellfish/oysters
  • open wound in water- bullous skin lesions!!
  • life threatening in immunocompromised- esp cirrhosis pts!!
38
Q

Aeromonas Hydrophila- sx, tx

A
  • gram neg, non-spore forming, rod-shaped, facultatively anaerobic bacteria, flagellum
  • fresh water!!
  • eating fish/shellfish!!
  • open wounds in water- necrotizing fasciitis aka flesh eating bacteria!!
  • 2 types- Cholera-like- rice water stools; Bloody
  • scuba divers that swallow fresh water then have gastroenteritis!
  • Tx- ampicillin
39
Q

Traveler’s Diarrhea- sx

A
  • 50% of travelers to developing countries
  • contaminated food/water
  • watery diarrhea
  • bloody diarrhea and fever UNCOMMON
  • self-limited
  • H2blocker/PPI- risk factors- lower pH
40
Q

Traveler’s Diarrhea- causes

A
  • ETEC- most common pathogen for TD!
  • campylobacter jejuni- asia
  • Salmonella, Shigella, Aeromonas, EAEC, norovirus, coronavirus
  • Giardia- Russia; campers!!
  • Cyclospora- Nepal
  • Norovirus- cruise ships
41
Q

E coli

A 
-children, elderly, travelers
ETEC- travelers!!- most common cause for TD
-watery diarrhea
-fecal leukocyte -
-diagnose clinically
-contaminated food/water
42
Q

E coli- O157:H7

A

EHEC- O157:H7- aka Shiga-toxin producing E coli (STEC)

  • bloody diarrhea
  • no fever
  • fecal leukocytes +
  • stool culture- shiga-like toxin
  • undercooked hamburger!!
  • HUS!!- children and if treated with abx!!
  • Tx- supportive, rehydration
43
Q

Yersinia enterocolitica- sx, complications, tx

A
  • higher risk in iron-overload syndromes!!!
  • bloody diarrhea!
  • abd pain + pharyngitis- suggests diagnosis
  • can mimic appendicitis!!!
  • clinically indistinguishable from salmonella or shigella!!
  • complications- hemochromatosis!
  • tx- supportive care
44
Q

Listeria monocytogenes

A
  • in pregnant women!!
  • non-bloody diarrhea!
  • Dx- blood culture!!!
  • stool cultures- select media!!
  • unpasteurized dairy and deli meats!!!
45
Q

Clostridium difficile

A
  • cytotoxin production
  • watery diarrhea
  • pseudomembranes!! on colonic mucosa
  • PCR for toxin (A and B)!!
  • abx especially- clindamycin, cephalosporins, fluoroquinolones!
  • wash hands with soap and water!!
46
Q

clostridium difficile- tx, complication

A
  • PO/IV metronidazole, oral vancomycin

- toxic megacolon

47
Q

Nosocomial infections

A
  • C difficile most common!!

- Norovirus- nursing homes

G2F (17 decks)

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