04-22 Gastroenteritis Flashcards Preview

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Flashcards in 04-22 Gastroenteritis Deck (43):
1

#1 cause of traveler's diarrhea worldwide?

ETEC

2

Food poisoning w/ onset in 1-6 hrs?

Staph aureus and Bacillus cereus

3

Food poisoning w/ onset in 8-14 hrs?

Clostridium perfringens
Bacillus cereus

4

Food poisoning w/ onset >16 hrs?

V. cholera & parahemolyticus
ETEC
Salmonella
Shigella

5

When I say mayo, cream pastry, ham or poultry you say?

staph aureus

6

When I say fried rice you say?

Bacillus cereus (also meat, beg, dried beans or cereals)

7

When I say shellfish you say?

Vibrio!
—V. cholera or V. parahemolyticus

8

When I say salad, cheese, meat or water you say?

ETEC

9

When I say poultry, eggs, dairy or beef you say?

Salmonella

10

When I say potato/egg salad, lettuce, raw veg you say?

Shigella

11

When I say beef, poultry, legumes or gravy you say?

Clostridium perfringens

12

When I say abx diarrhea you say?

C. diff

13

When I say diarrhea in MSM you say?

Hep A

14

When I say pet reptile or amphibian you say?

Salmonella

15

When I say diarrhea in HIV you think?

cryptosporidium, microsporidium
cyclospora
isospora

16

When I say diarrhea in pregnancy you think?

listeria or Hep E

17

When I say little kids, you think?

norovirus or rotavirus

18

Noninflammatory Diarrhea
—Presentation
—Pathogenesis
—Location
—Usual suspects

—Presents w/ WATERY stool (no blood or WBCs)
—Pathogenesis: secretory due to toxin
—Located usu. in prox SB
—Suspects:
——V. cholera
——ETEC
——Bacillus cereus
——Rotavir
——Giardia
——C. perfringens
——cryptosporidium

19

Inflammatory Diarrhea
—Presentation
—Pathogenesis
—Location
—Top 3 suspects

Presents w/ DYSENTERY (bloody/mucoid stool w/ WBCs)
Pathogenesis: invasion or cytotoxic
Located usu. in colon +/- T.I.
Usual Suspects:
—Shigella, Salmonella, Campylobacter
Other suspects
—EHEC & EIEC
—V. parahemolyticus
—C. diff
—Entamoeba histolytica
—Y. eneterolitica*

*May also be penetrating

20

Penetrating Diarrhea
—Presentation
—Pathogenesis
—Location
—Usual suspects

—Presentation: enteric FEVER
—Pathogenesis: complete invasion
—Location: distal SB
—Usual suspects:
——Salmonella typhi
——Y. enterolitica

21

Acute vs. persistant vs. chronic diarrhea

Acute = 0-14 days
Persistent = 15-30 days
Chronic > 30 days

22

When pt has tenesmus think

Shigella or STD causing rectal inflammation

23

If vomitting w/ diarrhea

consider toxin-mediated; ask about sick contacts

24

If presents w/ diarrhea + fever and/or severe abd pain think

invasive dz

25

If presents w/ diarrhea & abdominal bloating

ask about outdoor exposure

26

In what situations is further eval appropriate?

—bloody
—hypovolemia w/ profuse diarrhea
—hospitalized, immunocomp, preg
—fever >38.5 or other s/sx of systemic dz
—sx >48 hrs or >6 stools/24 hrs
—diarrhea s/p abx

27

What tests would you order for diarrhea w/u if needed?

Fecal WBCs or Lactoferrin
Stool culture (only 1-5% positivity)
—salmonella, shigella, campylobact, O157:H7, Shiga tox EIA
Ova & Parasites
—cryptosporidium, giardia, Entamoeba histolytica
C. diff PCR or antigen test
(rarely endoscopy)

28

Why no abx unless necessary?

EHEC may worsen w/ abx

29

When are abx indicated? Which ones?

fluoroquinolones or azithro if:
—severe (>8/day)
—prolonged (>7 days)
—Hospitalized or immunocompromised

30

Norovirus
—Pathophys
—Epi
—Presenation
—Dx
—Tx

1. Pathophys – damages brush border, preventing absorption
2. Epidemiology – outbreak association (nursing home, cruise ship)
3. Clinical - acute vom (esp kids), low fever in 1/3
—cramps +/- nonbloody diarrhea (esp adults) w/in 10-48hrs
—30% 2° attack rate
—Lasts 1-2 days in nl host
4. Diagnosis – PCR confirmation (state public health lab)
5. Treatment - supportive

31

Rotavirus
—Pathophys
—Epi
—Presenation
—Dx
—Tx

1. Pathophys: activated by proteolysis to infectious subviral particles
2. Epidemiology: Main cause of PEDI diarrhea
—important cause of global infant mortality
—Highest infection rates at ages 3-15 months
3. Clinical: 2 day incubation. Vom and watery diarrhea for 3-8 days
—can be associated with fever and abdominal pain.
4. Diagnosis: rapid antigen detection in stool.
5. Treatment: Supportive. Prevent. VACCINE available.

32

Shigella
—Species names
—Pathophys
—Epi
—Presenation
—Dx
—Tx

A. Species = S dysenteriae, flexneri, sonnei
1. Pathophysiology: invades colonic epithelium, → superficial ulcerations, colitis with crypt abscesses → impaired absorption → diarrhea
2. Epidemiology: 12-72 hr incub, fecal-oral transmission, predilection for children, daycare, poor sanitation,
MSM.
3. Clinical: dysentery, mod-severe w/ fever and blood flecks in stool; lasting 1-2 weeks
—kids can develop HUS (shiga toxin), mortality usually <1%.
4. Diagnosis: stool culture 5. Treatment: ampicillin standard but TMP/SMX and ciprofloxacin cover resistant strains; avoid anti-motility agents.

33

Salmonella typhi
—Pathophys
—Epi
—Presenation
—Dx
—Tx
—Px

Engineer and her baby back from India.
—Typhoid Mary (colonized, chronic carrier rare)

1. Pathophysiology: ingested organisms reach small bowel, penetrate mucosa, carried to lymph nodes and blood with 2° excretion into intestine from bile.
2. Epidemiology: 10 day incubation, human reservoir only.
3. Clinical: systemic illness with insidious onset of malaise, myalgias, headache and high fever.
—Classic rose spots (actually rare) and temp-pulse disassociation.
—Complications include intestinal perforation and chronic carriage.
4. Diagnosis: 80% positive blood cultures in early state, stool cultures positive late.
5. Treatment: ampicillin, TMP/SMX, ciprofloxacin; consider admission
6. Prevention: live oral vaccine

34

Other Salmonella spp.
—Species names
—Pathophys
—Epi
—Presenation
—Dx
—Tx

A. species = S enteritidis, typhimurium etc
1. Pathophysiology: pili adhere to small intestine where enterotoxin stimulates fluid secretion.
2. Epidemiology: 12-36 hour incubation, numerous animal reservoirs (poultry, eggs)
3. Clinical: gastroenteritis with sudden onset of nausea, crampy abdominal pain, diarrhea and fever.
4. Diagnosis: stool culture
5. Treatment: mild cases treated with fluids.
—TMP/SMX or cipro only for severe dz, imm compromise or extremes of age

35

Campylobacter jejuni
—Pathophys
—Epi
—Presenation
—Dx
—Tx
—Unique complication

1. Pathophysiology: invasive disease of ileum and colon with inflammatory diarrhea
2. Epidemiology: 1-7 d incubation, many animal reservoirs, transmission in poultry, unpasteurized milk, water.
3. Clinical: 12-24 prodrome of HA, myalgias, fever then acute diarrhea with >10 loose, non bloody BM/day. Lasts 5-7 days.
4. Diagnosis: stool culture
5. Treatment: controversial. (Cipro effective in vitro.)
6. Complication: Guillan-Barré syndrome (ascending paralysis)

36

Basics of the 4 E. coli syndromes

1. EPEC: adheres to and destroys microvilli
—childhood diarrhea in developing countries.
2. ETEC: milder, cholera-like watery diarrhea from prod of enterotoxin (LT or ST). Often traveler’s diarrh
3. EIEC shigella like inflammatory diarrhea
4. EHEC: cytotoxin causes bloody diarrhea
—may have HUS, 0157:H7 often implicated (poorly cooked HAMBURGER outbreaks).

37

C. diff
1. pathophys
2. epi
3. tx

1. Pathophysiology: anaerobic toxin producing bacteria causes diarrhea and can cause pseudomembranous colitis.
2. Epidemiology: antibiotic associated, 4-9 day incubation
3. Treatment: Oral metronidazole. Oral vancomycin for severe illness.

38

Y. parahemolyticus
—Pathophys
—Epi
—Presenation
—Dx
—Tx

1. Pathophysiology: mild tissue damage and watery diarrhea suggesting both invasion and toxin formation
2. Epidemiology: 24-hour incubation, inadequately cooked seafood
3. Clinical: explosive watery diarrhea with low grade fever
4. Diagnosis: stool culture (requires special media)
5. Treatment: supportive

39

V. cholera
—Pathophys
—Epi
—Presenation
—Dx
—Tx

1. Pathophysiology: non inflammatory toxin acts on small bowel; adenylate cyclase stimulation leads to increased cAMP and massive isotonic fluid loss
2. Epidemiology: 1-2 d incubation, food and water borne, seafood. Pandemics.
3. Clinical: watery diarrhea (rice-water stool) and dehydration without fever.
4. Diagnosis: stool culture, (requires special media)
5. Treatment: IV/PO fluid replacement. Tetracycline.

40

Listeria monocytogenes
—Pathophys
—Epi
—Presenation
—Dx
—Tx

1. Pathophysiology: intracellular pathogen, passes through intestines into macrophages and causes disseminated infec- tion
2. Epidemiology: Incubation period 2-6 weeks. Coleslaw, dairy products, cold processed meats. Immunocompromised host, extremes of age and pregnant women.
3. Clinical: Fever, myalgias, bacteremia and meningitis.
4. Diagnosis: Blood or CSF cultures
5. Treatment: Ampicillin

41

Best way to distinguish between inflamm or non-inflamm diarrhea?

fecal lactoferrin (WBC breakdown product)
—used to be fecal WBCs)

42

Definition of diarrhea?

>3 stools/day

43

Travel recommendation advice

Peel it, cook it, boil it or forget it.