Infectious diarrhea

Question 1

What are the two leading causes of death worldwide?

Answer 1

Pnuemonia

Diarrhea

Question 2

What causes morbidity and death in diarrhea?

Answer 2

Dehydration

Therefore, rehydration is mainstay of treatment

Question 3

Two types of diarrhea

Answer 3

Non-inflammatory (watery)
small bowel

Inflammatory (High T, WBC, RBC)
colon

Question 4

Definition of diarrhea

Answer 4

3 or more loose stools lasting more than 24 hrs

Question 5

Location and infectious organisms in non-inflammatory and inflammatory diarrhea)

Answer 5

Non-inflammatory:
Site: Upper small bowel
Pathogens: Norwalk, Rotavirus, Giardia, Cholera, ETEC

Inflammatory:
Site: Colon
Pathogens: C. jejuni, Shigella, Salmonella, +/- E. coli O157:H7* C. difficile, E. histolytica (protozoa)

Question 6

Pathogens Producing Watery Diarrhea

Answer 6

Vibrio cholerae
Enterotoxigenic E. coli
Rotavirus
Norwalk virus
Giardia lamblia

Question 7

Histology of cholera

Answer 7

Looks normal

Question 8

What is the leading cause of prolonged diarrhea, dehydration from diarrhea, hospitalization from diarrhea, death from diarrhea (U.S. and world)

Answer 8

Rotavirus

Question 9

Vaccine for rotavirus

Answer 9

Live, oral vaccine (>90% effective in US and 17-65% in developing countries)

Question 10

Who gets rotavirus the most?

Answer 10

Infants, young children

5-8 days duration of illness

Question 11

Norovirus

Answer 11

Older children, adults

Family and community epidemics

1-2 day duration of illness

Question 12

Giardia lamblia

Answer 12

Diarrhea, fatigue, abdominal cramps, bloating, malodorous stool, flatulence, weight loss

Question 13

Pathogens Producing Inflammatory Diarrhea (in order of how common they are)

Answer 13

Campylobacter jejuni
Salmonella sp.
Shigella sp.
E. coli 0157:H7
E. histolytica

Question 14

Most common cause of inflammatory diarrhea

Answer 14

Campylobacter jejuni

Question 15

Fecal leukocytes

Answer 15

Can be positive with inflammatory diarrhea and so can give antibiotics

Question 16

E. coli 0157:H7

Answer 16

Vast majority of hemorrhagic colitis in US
2-4 days duration
Highest rates in young children and elderly
Comes in meat

Question 17

Spectrum of illness of E. coli 0157:H7

Answer 17

Asymptomatic infection
Non-bloody diarrhea
Hemorrhagic colitis
Hemolytic uremic syndrome (HUS)
Thrombotic thrombocytopenic purpura (TTP)

Question 18

What causes illness with E. coly 0157:H7?

Answer 18

Verotoxin: Shiga-like toxin (SLT-I/II)
Binds especially to human renal endothelial cells
Inhibits protein synthesis

Question 19

What is the leading cause of nosocomial diarrhea?

Answer 19

C. difficile

Question 20

Diagnosis of nosocomial diarrhea

Answer 20

Don’t need to do culture or parasite exam

If someone has been in hospital more than 3 days or has been taking antibiotics, think C. diff

Question 21

C. diff

Answer 21

Antibiotic-associated colitis
Nosocomial diarrhea
Toxin A/Toxin B
Antibodies important

mild diarrhea, watery or bloody, or may have fever, leukocytosis with severe colitis

Fecal transplant

Question 22

Enteric Fever (sites and pathogens)

Answer 22

Site: Nodes; Blood; Gallbladder
Pathogens: Salmonella typhi, S. paratyphi, ±Yersinia

Question 23

Salmonella enteric serotype typhi

Answer 23

Typhoid fever

Gram negative rod; Human only

Cases/year:

Question 24

What’s wrong?

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

Answer 24

Enterotoxigenic E. coli

Question 25

What’s wrong?

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 25

Vibrio cholerae

Question 26

What’s wrong?

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 26

Giardia lamblia

Question 27

What’s wrong?

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 27

E. coli 0157:H7

Question 28

What’s wrong?

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

Answer 28

Clostridium difficile