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Flashcards in Acute diarrhea--bacterial causes Deck (47):
1

diarrhea- definition

-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!!

2

noninfectious causes

-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!!

3

epidemiology

-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!

4

most frequent causes of infection

Salmonella and Campylobacter

5

Acute infectious diarrhea- transmission

-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

6

bacterial toxins, enterotoxin-producing bacteria

small-bowel hyper-secretion
-water diarrhea
-vomiting
-minimal or no fever
-after a few hrs after ingestion

7

entero-adherent pathogens

small-bowel hyper-secretion
-less vomiting
-greater abd cramping/bloating
-higher fever

8

cytotoxin-producing and invasive microorganisms

-high fever
-abd pain

9

5 high risk groups in US

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

10

discriminations from true diarrhea

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

11

diarrhea- indications for evaluation

-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

12

work-up cornerstone of diagnosis

-microbiologic analysis of stool
-if stool studies unrevealing- endoscopy may be indicated

13

routine stool culture includes?

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

14

stool culture- need to ask specifically for?

-C diff PCR/toxin
-ova parasites
-stool ag (parasites- giardia, cryptosporidium)

15

labs

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

16

radiology

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

17

food poisoning- chicken

salmonella, campylobacter, shigella

18

food poisoning- undercooked hamburfer

-EHEC (O157:H7)

19

food poisoning- fried rice or other reheated food

-Bacillus cereus

20

Food poisoning- potato salad, mayonnaise, cream pastries

-Staph aureus

21

food poisoning- eggs

-Salmonella

22

food poisoning- Lunch meat, soft cheeses

-Listeria

23

food poisoning- seafood

-Vibrio species, Salmonella, acute hep A
-Norwalk, campylobacter

24

Staphylococcus Aureus

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

25

Bacillus Cereus

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

26

Clostridium Perfringens

-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

Shigella

-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

Shigella- tx, complications

-Bismuth, ampicillin, fluoroquinolone, or TMP/SMX
-resp complaints and seizures
-reactive arthritis!

29

Salmonella typhimurium

-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

Salmonella typhimurium- complications, tx

-abx usually not indicated
-septic arthritis, osteomyelitis!

31

Salmonella typhi- sx, dx, tx

-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

Campylobacter jejuni

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

33

Campylobacter jejuni- complications, Tx

-Guillian-Barre syndrome!!
-supportive

34

Vibrio cholerae

-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

Vibrio cholerae- dx, tx

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

36

Vibrio parahemolyticus

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

37

Vibrio Vulnificus

-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

Aeromonas Hydrophila- sx, tx

-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

Traveler's Diarrhea- sx

-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

Traveler's Diarrhea- causes

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

41

E coli

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

42

E coli- O157:H7

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

Yersinia enterocolitica- sx, complications, tx

-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

Listeria monocytogenes

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

45

Clostridium difficile

-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

clostridium difficile- tx, complication

-PO/IV metronidazole, oral vancomycin
-toxic megacolon

47

Nosocomial infections

-C difficile most common!!
-Norovirus- nursing homes