Common GI Infections Flashcards
What type of diarrhea is caused by infections in the
- Small intestine
- Large intestine
- Watery and/or malabsorptive diarrhea
2. Inflammatory diarrhea
Diarrhea definition
3 or more loose stools per day
“Stool that conforms to the shape of its container”
3 physiological causes of diarrhea
More fluid secreted into the lumen than the gut can absorb (secretory or osmotic) Normal secretion but impaired absorption (malabsorptive) Inflamed mucosa (leakage of fluid plus impaired absorption, frequently with pus/blood)
How can you tell the difference between 1. Secretory 2. Osmotic 3. Malabsorptive 4. Inflammatory diarrhea?
- Typically water, minimal fever, continues with fasting/diet
- Due to overingestion of osmotic agents
- Frequently with foul smell/gas (fermentation of nonabsorbable sugars) and/or greasy stools
- Fever, bloody stool, WBCs in stool
Where is the time cut off for chronic diarrhea?
> 14 days
Secretory infectious bacteria
Caused by bacteria that adhere to but do not damage the intestinal epithelium
They secrete toxins that turn on fluid secretion
Can overwhelm the ability of the gut to absorb fluid, leading to massive intestinal fluid losses
2 steps in the management of watery diarrhea
Volume repletion (oral rehydration preferred, can give IV if unconscious) Antibiotics (but all infections are self limited)
Malabsorptive diarrheal infections
Infection of small intestine, leading to villus blunting
Mild inflammation = increased secretion
Damaged villi = impaired absorption
Ex: Giardia, E. coli, Norovirus
Inflammatory enterocolitis
Refers to bacteria (or amoeba) that attach to and invade the small and/or large intestinal epithelia
Symptoms: diarrhea with blood and/or pus, fever, cramps, prostration
Dystenery
A disease characterized by severe diarrhea with passage of mucus and blood and usually caused by infection
A type of inflammatory colitis
Can have tenesmus
Tenesmus
Sensation of having to poop, then you go but you still feel like you need to
From swelling in the rectal mucosa
5 common causes of dysentery
Non-typhoidal Salmonella Campylobacter jejuni Shigella spp. Entamoeba histolytica Clostridium difficile (sort of)
How is dysentery transmitted
Through food/water, fomites, or direct person-to-person
How is 1. Shigella 2. Salmonella 3. Campylobacter spread?
- Person to person (low number of organisms needed for infection)
2 and 3. Through food and water
Shigella
Gram negative rod
4 subspecies, almost identical to E. coli
Invades epithelial cells directly leading to cell death
Classic cause of bacillary dysentery
S. dysenteriae 1 also expresses a shigatoxin that can lead to HUS
Infections from fecal contamination of food or water
Oral rehydration and antibiotics are used for eradication (antibiotics not really needed)