Biochemistry - University of Arizona



Pathology

Lecture 43 Intestinal Infections and Inflammation

1) To be familiar with abnormal patterns of fluid/stool handling in the GI tract.

Diarrhea is stool production in excess of 250 g containing 70-95% water. Dysentery is low-volume, painful, bloody diarrhea.

Secretory diarrhea: net intestinal fluid secretion, >500 mL isotonic fluid.

Osmotic diarrhea: high luminal osmolarity, >500 mL, abates upon fasting.

Exudative diseases: mucosal destruction leads to output of purulent bloody stools.

Deranged motility: improper gut neuromuscular function, highly variable patterns.

Malabsorption: produces voluminous, bulky stools with increased osmolarity and combined with excess stool fat (steatorrhea).

2) To know the basic elements of GI tract protection against infection, and the broad categories of pathogenesis in GI infection.

Protective mechanisms:

Intrinsic to GI tract: gastric acidity, native intestinal flora (competition, toxic metabolites), bowel motility, local immune response (GALT, IgA), digestive enzymes, and other (intestinal mucus, bile).

Behavioral/social: personal hygiene and community sanitation.

Broad categories of pathogenesis:

- Organisms specifically pathogenic for GI tract.

- Native mixed flora of GI tract become pathogenic due to decreased bowel integrity, risk of peritonitis, septicemia.

3) For the various viral, bacterial, protozoal, and metazoal diseases of GI tract, be able to recognize the following (in each group): common infectious agents, clinical manifestations, at-risk population groups, pathologic features, and special features.

|Disease |Infectious agents |Clinical manifestation |At-risk pop. |Pathologic features |Special features |

|Viral |Rotavirus |Nausea, vomiting, watery |Infants ................
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