What are the four pathophysiologic mechanisms of diarhhea?
Osmotic, secretory, inflammatory, malabsorptive.
What characterizes acute diarrhea, persistent, chronic?
acute: < 14 days
persistent: > 14 days
chronic: > 30 days
How does small bowel diarrhea present?
Large volume watery stool
mid abdominal pain.
How does colon ("dysenteric") diarrhea present?
Small volume stool with blood and tenesmus
lower abdominal pain
red cells and leukocytes in the stool.
Name 7 bacteria that preferentially affect the small bowel?
Salmonella, E. coli, Staph aureus, C. perfringens, B. Cereus, V. cholerae, Aeromonas hydrophila.
Name two viruses that affect the small bowel preferentially?
Name 6 bacteria that preferentially affect the colon?
Campylobacter, Shigella, Yersinia, Enteroinvasive E. coli, C. difficile, Vibrio parahaemolyticus.
Name three viruses that affect the colon preferentially?
CMV, Adenovirus, Herpes simplex.
What is the only protozoa that affects the colon preferentially?
What is the leading cause of foodborne illness in the US?
Non typhoid salmonella.
Who is at higher risk for E. Histolytica infection and diarrhea?
Institutionalized patients, homosexuals
Found mostly in migrants and travelers.
What is the pathogenesis of Cholera diarrhea?
Cholera toxin activates adenylate cyclase, increasing cAMP -> activated Cl channel -> increased Cl secretion and decreased Na absorption -> more ions in lumen -> more water in lumen -> voluminous diarrhea.