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13 Cards in this Set
- Front
- Back
What is Diarrhea?
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passage of abnormal liquid or unformed stools associated with increased frequency of defecation
results in derangement in the normal physiology if the intestinal handling of water and electrolyte absorption and secretion |
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What is the normal physiology of the GI tract?
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It stores, propels, mixes and digests food
Secretes enzymes and fluids after ingestion Selectively absorbs water, electrolytes and nutrients Diarrheal syndromes result from disturbances in any of the basic pathophysiological processes including osmosis, active secretion exudation, inflammation and altered motility |
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What is secretory diarrhea?
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A number of disease processes may produce secretory diarrhea
Basic pathophysiology involves either net secretion of ions or inhibition of net sodium absorption Net intestinal secretion is most often secondary to the stimulation of active chloride secretion and to the inhibition of active absorption of sodium and chloride by messengers such as cAMP Mostly caused by infection were pathogens affect the GI Pathogens adhere to the mucosa disrupting the absorptive/secretory process of the enterocytes without causing acute inflammation or mucosal destruction |
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What is osmotic diarrhea?
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Can result from over-eating, sudden dietary change, maldigestion or malabsorption
Malabsorbtion can be caused by anything affecting the mucosal or submucosal layers of the intestine |
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What is inflammatory diarrhea?
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Exudation or inflammation can contribute to diarrhea when the intestinal epithelium's barrier function is compromised by loss of epitheilal cells or disruption of tight junctions
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What are the mechanisms that infections use and cause diarrhea?
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Enterotoxins that subvert the regulatory mechanisms of enterocytes
Cytotoxins that destroy enterocytes Adherence to mucosa by organisms that alter enterocyte function Invasion of the mucosa by organisms that provoke an inflammatory response by the immune system Ingestion of preformed toxins |
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What is functional/ motility diarrhea?
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Isolated acceleration of intestinal transit is a poorly recognized mechanism of diarrhea
Accelerated transit may be a major factor in diarrhea that is associated with endocrine disorders, neoplasia or in humans diagnosed with irritable bowel syndrome Intestinal transit may also be accelerated in many diarrheal states because of stimulation of peristalsis by increased intraluminal volumes |
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What are the differentials for a 4 day old holstein calf who was normal the night before but is now recumbant, anorexic, hypothermic, dehydrated and has yellow pasty feces on the tail and perineum?
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E.coli (most likely)
Rotavirus coronavirus Too young for salmonella and BVD |
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What is the pathogenesis of enterogenic E.coli?
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Oral exposure to fecal coliforms leads to colonization in the gut with the normal commensal flora
The organisms are ingested and are able to produce disease caused by the presence of two virulence factors and heat stable toxin K99 fimbria Organisms through the GI tract with ingesta Colonized in distal small intestine and attach to epithelium allowing bacteria to maintain residence in the small intestine and multiplies instead of being passed |
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What type of diarrhea does entertoxicgenic E.coli cause?
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Secretory diarrhea
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Why is this infection more common in young calves?
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pH of abomasum and intestine
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Why does it predominantly affect the small intestine?
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There is more expression of these receptors in small intestine
Because the toxins are pH dependent |
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How would you treat animal with this enterotoxigenic E coli?
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Antibiotics and fluids
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