04-22 Gastroenteritis Flashcards
(43 cards)
1
Q
1 cause of traveler’s diarrhea worldwide?
A
ETEC
2
Q
Food poisoning w/ onset in 1-6 hrs?
A
Staph aureus and Bacillus cereus
3
Q
Food poisoning w/ onset in 8-14 hrs?
A
Clostridium perfringens
Bacillus cereus
4
Q
Food poisoning w/ onset >16 hrs?
A
V. cholera & parahemolyticus
ETEC
Salmonella
Shigella
5
Q
When I say mayo, cream pastry, ham or poultry you say?
A
staph aureus
6
Q
When I say fried rice you say?
A
Bacillus cereus (also meat, beg, dried beans or cereals)
7
Q
When I say shellfish you say?
A
Vibrio!
—V. cholera or V. parahemolyticus
8
Q
When I say salad, cheese, meat or water you say?
A
ETEC
9
Q
When I say poultry, eggs, dairy or beef you say?
A
Salmonella
10
Q
When I say potato/egg salad, lettuce, raw veg you say?
A
Shigella
11
Q
When I say beef, poultry, legumes or gravy you say?
A
Clostridium perfringens
12
Q
When I say abx diarrhea you say?
A
C. diff
13
Q
When I say diarrhea in MSM you say?
A
Hep A
14
Q
When I say pet reptile or amphibian you say?
A
Salmonella
15
Q
When I say diarrhea in HIV you think?
A
cryptosporidium, microsporidium
cyclospora
isospora
16
Q
When I say diarrhea in pregnancy you think?
A
listeria or Hep E
17
Q
When I say little kids, you think?
A
norovirus or rotavirus
18
Q
Noninflammatory Diarrhea —Presentation —Pathogenesis —Location —Usual suspects
A
—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
Q
Inflammatory Diarrhea —Presentation —Pathogenesis —Location —Top 3 suspects
A
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
Q
Penetrating Diarrhea —Presentation —Pathogenesis —Location —Usual suspects
A
—Presentation: enteric FEVER —Pathogenesis: complete invasion —Location: distal SB —Usual suspects: ——Salmonella typhi ——Y. enterolitica
21
Q
Acute vs. persistant vs. chronic diarrhea
A
Acute = 0-14 days
Persistent = 15-30 days
Chronic > 30 days
22
Q
When pt has tenesmus think
A
Shigella or STD causing rectal inflammation
23
Q
If vomitting w/ diarrhea
A
consider toxin-mediated; ask about sick contacts
24
Q
If presents w/ diarrhea + fever and/or severe abd pain think
A
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.
