Infectious Diarrhea

Question 1

Two leading causes of death worldwide

Answer 1

pneumonia

diarrhea

Question 2

What is the leading cause of morbidity and death in diarrhea? Mainstay of therapy?

Answer 2

dehydration

rehydration is mainstay of therapy

Question 3

infectious gastroenteritis in US

Answer 3

viral 30-40%
bac/parasitic 20-30%
unknown 40%

Question 4

Types of diarrhea

Answer 4

Non-inflammatory (watery)
small bowel

Inflammatory (increased T, fecal WBC, RBC)
colon

Question 5

Definition of diarrhea

Answer 5

3+ watery stools in over 24 hrs

Question 6

non-inflammatory diarrhea site and pathogens

Answer 6

Site: Upper small bowel Pathogens: Norwalk, Rotavirus, Giardia, Cholera**, ETEC (traveler’s)

Question 7

inflammatory diarrhea site and pathogens

Answer 7

Site: Colon
Pathogens: **C. jejuni (number 1 in kids and adults), Shigella, Salmonella, E. coli O157:H7 (bloody diarrhea), C. difficile (esp w/ abx), E. histolytica

Question 8

Pathogens producing watery diarrhea

Answer 8

Vibrio cholerae
Enterotoxigenic E. coli
Rotavirus
Norwalk virus
Giardia lamblia

Question 9

Cholera histology

Answer 9

cholera binds to epithelial cells but doesn’t cause any overt pathology on histology (looks normal)

(leads to chloride secretion, water follows)

Question 10

What does cholera diarrhea look like?

Answer 10

rice water stool (secreting lots of mucin)

• no blood
• up to 24L/d

Question 11

Signs of dehydration

Answer 11

decreased pulse volume
 low BP
 poor skin turgor
 sunken eyes
 decreased urine
 decreased MS
 metabolic acidosis --(losing bicarb)
 hypoglycemia
 hypokalemia

Question 12

Predominant cause of nosocomial diarrhea

Answer 12

C. diff

Question 13

Cause of traveler’s diarrhea

Answer 13

Enterotoxigenic E. coli

Question 14

Rotavirus

Answer 14

Leading cause of:
Prolonged diarrhea
Dehydration from diarrhea
Hospitalization from diarrhea
Death from diarrhea (U.S. and world)

Poorest countries =82% of deaths

Question 15

Effectiveness of oral vaccines for rotavirus

Answer 15

> 90% in US against severe diarrhea (esp hosp/death)

in developing countries 17-65%

Question 16

Who gets affected by Norovirus, rotavirus

Answer 16

norovirus: older kids, adults
rotavirus: infants, young children

Question 17

Transmission norovirus and rotavirus

Answer 17

norovirus: fecal-oral, contaminated shellfish and water
rotavirus: fecal-oral

Question 18

incubation period norovirus and rotavirus

Answer 18

norovirus 1-2 d

rotavirus 1-3 d

Question 19

incuabation period and Duration of illness norovirus, rotavirus

Answer 19

incubation period

norovirus: 1-2d
rotavirus: 1-3 d

duration of illness

norovirus: 1-2 d (comes on fast, goes away fast)
rotavirus: 5-8 d

Question 20

epidemiology norovirus, rotavirus

Answer 20

norovirus: family and community epidemics, often winter
rotavirus: sporadic cases, usually winter, occ epidemic

Question 21

Giardia

Answer 21

diarrhea, bloating, gas, fatty/malodorous stools, flatulence, vomiting, fever, fatigue, cramps, weight loss

Question 22

Pathogens for Inflammatory diarrhea

Answer 22

most common in kids and adults: **campylobacter jejuni

Others:
Salmonella sp.
Shigella sp.
E. coli 0157:H7
E. histolytica

Question 23

E. coli 0157:H7

Answer 23

Causes vast majority of hemorrhagic colitis (and HUS) in U.S.
Illness lasts 2-4 days (

Question 24

Therapy of E. coli 0157:H7

Answer 24

Prevention (food, cooking)

?IV Ig

Question 25

Nosocomial diarrhea

Answer 25

``` C. diff (virtually only coause) -commonly associated w/ abx use -gram positive rod -can cause pseudomembranous colitis (may have to remove colon) -Toxin A/Toxin B (epidemic strain B1) Therapy: antibiotics Recurrence: 15-26% (bug can persist) Other option: fecal transplant, pills of fecal mibrobiata ``` Sx: mild diarrhea, watery or bloody, or may have fever, leukocytosis with severe colitis

Question 26

Enteric Fever sites and pathogens

Answer 26

site:Nodes; Blood;Gallbladder Pathogens: Salmonella typhi,S. paratyphi, ± Yersinia Salmonella: gram negative rod risks: fecal contamination food/water contact w/ carrier

Question 27

College student goes to Mexico for summer vacation, acute, non-inflammatory diarrhea (watery stool, no blood, no fever)

Answer 27

EHEC

Question 28

Embassy official travels to Peru; enjoys ceviche at a state dinner; does not enjoy acute abd. pain, profuse watery diarrhea (20/day) which develops 2 days later; No fever, blood. Several others ill.

Answer 28

vibrio cholerae

Question 29

American trekker in Nepal develops acute abd. pain, bloating, gas, foul-smelling diarrhea. No blood, fever. Does not respond to quinolones; loses 10 lbs.

Answer 29

Giardia

Question 30

Embassy official, well-recovered, arrives in Seattle, kisses ground, and, craving real American food, takes family to Jack-in-the Box. Four days later, develops abd. pain, grossly bloody diarrhea. No fever.

Answer 30

E. coli 0157:H7

Question 31

Physician traveler, anxious about travelers' diarrhea, takes amoxacillin-clavulanate while on CME boondoggle in Tahiti. Develops acute watery diarrhea, mild fever, guaiac positive.

Answer 31

C. diff