Part 1: Alterations in Digestive Function
Describe the etiology and physiologic mechanisms for:
-anorexia - side effect of medication, nausea, anxiety, psychological (anorexia nervosa); suppression of hunger center in the brain
-nausea and vomiting - both caused by activation of the vomiting center in the brain - caused by motion (car, plane, boat), drugs, mechanical obstruction, psychological problems; used to eliminate harmful substance from the body; psychogenic vomiting used to express hostility, anxiety, to avoid unpleasant event (e.g. going to school) (Berkow, Beers and Fletcher, a997, 512)
-diarrhea - osmotic, when substances can't be absorbed from the intestine; secretory, when small and large intestine secrete salts into stool due to toxins; malabsorption syndrome, food not digested normally; exudative, inflammation of lining of large intestine; bacterial overgrowth, by normal bacteria, or growth of bacteria not normally present; surgical reduction of length of large intestine; caused by having more water than normal in stool (>90 percent) (522-523).
Characterize the appearance of blood in vomitus and stool according to the site and extent of bleeding:
-vomitus - can be bright red or dark, depending on whether there has been time for hemoglobin to be acid-denatured or not; can be from esophagus, stomach, or nasopharyngeal and oral structures (Gastrointestinal, 2005)
-stool - black stool usually indicates upper GI bleeding; at least 200 ml needs to be lost before appearance in stool; maroon or bright red stool indicates blood is coming from large bowel or rectum, but sometimes from massive upper GI bleed; black stool can be from bleeding ulcer, gastritis, esophageal varices, or Mallory-Weiss tear from violent vomiting; maroon stool from above causes plus diverticular bleeding, vascular malformation, intestinal infection, inflammatory bowel disease, tumor, colon polyps or colon cancer; bright red from all ...