Infectious diarrhea Flashcards
What are the two leading causes of death worldwide?
Pnuemonia
Diarrhea
What causes morbidity and death in diarrhea?
Dehydration
Therefore, rehydration is mainstay of treatment
Two types of diarrhea
Non-inflammatory (watery)
small bowel
Inflammatory (High T, WBC, RBC)
colon
Definition of diarrhea
3 or more loose stools lasting more than 24 hrs
Location and infectious organisms in non-inflammatory and inflammatory diarrhea)
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)
Pathogens Producing Watery Diarrhea
Vibrio cholerae Enterotoxigenic E. coli Rotavirus Norwalk virus Giardia lamblia
Histology of cholera
Looks normal
What is the leading cause of prolonged diarrhea, dehydration from diarrhea, hospitalization from diarrhea, death from diarrhea (U.S. and world)
Rotavirus
Vaccine for rotavirus
Live, oral vaccine (>90% effective in US and 17-65% in developing countries)
Who gets rotavirus the most?
Infants, young children
5-8 days duration of illness
Norovirus
Older children, adults
Family and community epidemics
1-2 day duration of illness
Giardia lamblia
Diarrhea, fatigue, abdominal cramps, bloating, malodorous stool, flatulence, weight loss
Pathogens Producing Inflammatory Diarrhea (in order of how common they are)
Campylobacter jejuni Salmonella sp. Shigella sp. E. coli 0157:H7 E. histolytica
Most common cause of inflammatory diarrhea
Campylobacter jejuni
Fecal leukocytes
Can be positive with inflammatory diarrhea and so can give antibiotics
E. coli 0157:H7
Vast majority of hemorrhagic colitis in US
2-4 days duration
Highest rates in young children and elderly
Comes in meat
Spectrum of illness of E. coli 0157:H7
Asymptomatic infection Non-bloody diarrhea Hemorrhagic colitis Hemolytic uremic syndrome (HUS) Thrombotic thrombocytopenic purpura (TTP)
What causes illness with E. coly 0157:H7?
Verotoxin: Shiga-like toxin (SLT-I/II)
Binds especially to human renal endothelial cells
Inhibits protein synthesis
What is the leading cause of nosocomial diarrhea?
C. difficile
Diagnosis of nosocomial diarrhea
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
C. diff
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
Enteric Fever (sites and pathogens)
Site: Nodes; Blood; Gallbladder
Pathogens: Salmonella typhi, S. paratyphi, ±Yersinia
Salmonella enteric serotype typhi
Typhoid fever
Gram negative rod; Human only
Cases/year:
What’s wrong?
College student goes to Mexico for summer vacation, acute, non-inflammatory diarrhea (watery stool, no blood, no fever)
Enterotoxigenic E. coli
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.
Vibrio cholerae
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.
Giardia lamblia
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.
E. coli 0157:H7
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.
Clostridium difficile
