Infectious Diarrhea Flashcards
Two leading causes of death worldwide
pneumonia
diarrhea
What is the leading cause of morbidity and death in diarrhea? Mainstay of therapy?
dehydration
rehydration is mainstay of therapy
infectious gastroenteritis in US
viral 30-40%
bac/parasitic 20-30%
unknown 40%
Types of diarrhea
Non-inflammatory (watery)
small bowel
Inflammatory (increased T, fecal WBC, RBC)
colon
Definition of diarrhea
3+ watery stools in over 24 hrs
non-inflammatory diarrhea site and pathogens
Site: Upper small bowel Pathogens: Norwalk, Rotavirus, Giardia, Cholera**, ETEC (traveler’s)
inflammatory diarrhea site and pathogens
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
Pathogens producing watery diarrhea
Vibrio cholerae Enterotoxigenic E. coli Rotavirus Norwalk virus Giardia lamblia
Cholera histology
cholera binds to epithelial cells but doesn’t cause any overt pathology on histology (looks normal)
(leads to chloride secretion, water follows)
What does cholera diarrhea look like?
rice water stool (secreting lots of mucin)
- no blood
- up to 24L/d
Signs of dehydration
decreased pulse volume low BP poor skin turgor sunken eyes decreased urine decreased MS metabolic acidosis --(losing bicarb) hypoglycemia hypokalemia
Predominant cause of nosocomial diarrhea
C. diff
Cause of traveler’s diarrhea
Enterotoxigenic E. coli
Rotavirus
Leading cause of: Prolonged diarrhea Dehydration from diarrhea Hospitalization from diarrhea Death from diarrhea (U.S. and world)
Poorest countries =82% of deaths
Effectiveness of oral vaccines for rotavirus
> 90% in US against severe diarrhea (esp hosp/death)
in developing countries 17-65%
Who gets affected by Norovirus, rotavirus
norovirus: older kids, adults
rotavirus: infants, young children
Transmission norovirus and rotavirus
norovirus: fecal-oral, contaminated shellfish and water
rotavirus: fecal-oral
incubation period norovirus and rotavirus
norovirus 1-2 d
rotavirus 1-3 d
incuabation period and Duration of illness norovirus, rotavirus
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
epidemiology norovirus, rotavirus
norovirus: family and community epidemics, often winter
rotavirus: sporadic cases, usually winter, occ epidemic
Giardia
diarrhea, bloating, gas, fatty/malodorous stools, flatulence, vomiting, fever, fatigue, cramps, weight loss
Pathogens for Inflammatory diarrhea
most common in kids and adults: **campylobacter jejuni
Others: Salmonella sp. Shigella sp. E. coli 0157:H7 E. histolytica
E. coli 0157:H7
Causes vast majority of hemorrhagic colitis (and HUS) in U.S.
Illness lasts 2-4 days (
Therapy of E. coli 0157:H7
Prevention (food, cooking)
?IV Ig
Nosocomial diarrhea
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
Enteric Fever sites and pathogens
site:Nodes; Blood;Gallbladder Pathogens: Salmonella typhi,S. paratyphi, ± Yersinia
Salmonella: gram negative rod
risks: fecal contamination
food/water
contact w/ carrier
College student goes to Mexico for summer vacation, acute, non-inflammatory diarrhea (watery stool, no blood, no fever)
EHEC
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
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
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
Physician traveler, anxious about travelers’ diarrhea, takes amoxacillin-clavulanate while on CME boondoggle in Tahiti. Develops acute watery diarrhea, mild fever, guaiac positive.
C. diff
