Diarrhea Flashcards
What are 3 major functions performed by the GI tract?
- Propels, mixes and digest food.
- Secretes enzymes and fluids after ingestion.
- Selectively absorbs water, electrolytes and nutrients.
Increased stool output, passage of abnormally fluid or unformed stools usually associated with increased frequency and/or volume of feces is known as what?
Diarrhea
T/F: There is a constant bidirectional flux of water and ions across the small intestinal mucosa.
True
Water moves in response to what?
Osmotic gradients
Where does absorption primarily occur?
Secretion?
- Enteric villi
- Intestinal crypts
Are villi found in the small intestine, large intestine or both?
Small intestine
With diarrhea, does the absorptive process exceeds the secretory process in magnitude, or does the secretory process exceeds the absorptive process?
The secretory process exceeds the absorptive process.
Different disease processes can convert portions of the GI tract from a what to a what?
An absorptive organ into a secretory organ.
What are 4 pathophysiologic mechanisms of diarrhea?
- Osmotic (malabsorption/maldigestion)
- Secretory
- Increased permeability (exudative)
- Altered motility
What type of diarrhea may develop when osmotically active molecules remain in the intestinal lumen (malabsorption)?
Osmotic diarrhea
When osmotically active molecules remain in the intestinal lumen, water movement from where to where is promoted?
From plasma to the intestinal lumen .
What happens to the absorptive capability of the small and large intestine with osmotic diarrhea?
They are overwhelmed.
What is a possible cause of osmotic diarrhea?
Sudden dietary changes.
What type of diarrhea can occur when there is interference with digestion and therefore the absorption of nutrients?
Osmotic diarrhea
T/F: What is not digested cannot be absorbed.
True
Unabsorbed solutes that remain in the intestinal lumen act as what?
Osmotic agents resulting in diarrhea.
What are 2 examples of conditions that can lead to osmotic diarrhea?
- Exocrine pancreatic insufficiency in dogs
- TGE in young pigs
Why are dogs with exocrine pancreatic insufficiency unable to digest food properly?
Decreased amount of pancreatic enzymes.
How do the feces of dogs with exocrine pancreatic insufficiency appear?
Voluminous, place and full of fat (steatorrhea).
The presence of excess fat in the stools, usually caused by disease of the pancreas or intestine, is known as what?
Steatorrhea
Is secretory diarrhea a result of an active or passive mechanism?
Active mechanism
Secretory diarrhea is usually caused by what?
Infectious agents (bacteria, viruses)
Pathogens may adhere to the mucosa disrupting the absorptive/secretory processes of enterocytes without causing significant damage to the cells with what type of diarrhea?
Secretory diarrhea
With secretory diarrhea, certain bacterial toxins activate the secretion of what?
Sodium, chloride and other electrolytes.
T/F: Electrolytes follow water secretion, overwhelming the absorptive capability of the intestine.
False - water follows electrolyte secretion.
Disease resulting in mucosal damage and inflammation can lead to what type of diarrhea?
Increased permeability (exudative) diarrhea
What does the loss of the normal epithelial lining (tight junctions) seen with increased permeability (exudative) diarrhea lead to?
Passive loss of fluid (serous proteins, blood, etc.)
What is an example of a cause of increased permeability (exudative) diarrhea?
Rhodococcus equi-induced enterocolitis in foals
Are primary disorders of motility common or uncommon in veterinary medicine?
Uncommon
Most causes of diarrhea can lead to what?
What does this contribute?
- Secondary decrease in segmental contractions.
- Contributes to diarrhea due to decrease resistance to the caudal movement of the ingesta.
What are the 2 types of movement seen in the GIT?
- Segmental
- Peristaltic
Why might intestinal transit be accelerated in many forms of diarrheal states?
Stimulation of peristalsis by increased intraluminal volumes.
T/F: Regarding the pathophysiologic mechanisms of diarrhea there is considerable overlap with more than one mechanism involved in a single patient.
True
Is diarrhea or vomiting seen as the result of disease within the GI tract considered a primary or a secondary gastrointestinal disease?
Primary
Is diarrhea or vomiting seen as a manifestion of disease somewhere else in the body considered a primary or a secondary gastrointestinal disease?
Secondary
What are 2 examples of secondary gastrointestinal disease?
- Exocrine pancreatic insufficiency
- Renal disease
T/F: Many cases of acute diarrhea are self-limiting.
True
What are 2 dietary causes of acute diarrhea?
- Dietary indiscretion
- Dietary intolerance
What are 3 examples of infectious causes of acute diarrhea?
- Parvovirus enteritis in dogs
- Panleukopenia in cats
- Salmonellosis
Pancreatitis can lead to what type of diarrhea?
Acute diarrhea
Diagnosis of which type of diarrhea often requires a more extensive work-up?
Chronic diarrhea
What are 3 examples of causes for chronic diarrhea?
- Inflammatory Bowel Disease (IBD)
- Gastro-intestinal neoplasia
- Chronic parasitism/fungal infections
What are 4 pathophysiologic mechanisms of diarrhea?
- Osmotic (malabsorption/maldigestion)
- Secretory
- Increased permeability (exudative)
- Altered motility
Main pathophysiologic mechanism of diarrhea in Johne’s disease is what?
Increased permeability (exudative)
Classical cause for secretory diarrhea is what?
E. coli
What is the main pathophysiologic mechanism of diarrhea seen with porcine proliferative enteropathy caused by Lawsonia intracellularis?
Increased permeability (exudative)
Main pathophysiologic mechanism of diarrhea for crypto is what?
Osmotic malabsorption/maldigestion
What is the main pathophysiologic mechanism of diarrhea with blackhead disease?
Increased permeability (exudative)
