上海交通大学：《诊断学》课程PPT教学课件（英语版）Chapter 7 Diarrhea

Diarrhea Definition increase in the frequency of bowel movements increase in stool liquidity in some cases increase in daily stool weight >200g/d)

Diarrhea Definition • increase in the frequency of bowel movements • increase in stool liquidity • in some cases increase in daily stool weight (>200g/d)

Pathophysiological mechanisms secretory diarrhea(increased intestinal secretion) Osmotic diarrhea Decreased intestinal surface area and/or intestinal absorption Rapid transit of intestinal contents(shortened transit time)

Pathophysiological mechanisms • secretory diarrhea (increased intestinal secretion) • Osmotic diarrhea • Decreased intestinal surface area and/or intestinal absorption • Rapid transit of intestinal contents (shortened transit time)

Pathophysiological mechanisms secretory diarrhea (increased intestinal secretion) active Adenylate CAMP NaCI↑ agents secretory cyclase system diarrhea .s infections(cholera toxin, E-col, salmonella, staphylococcal) 今 Hormonal( Gut hormones,ZES,ⅤmP), cancer(calcitonin, Prostaglandins) . o miscellaneous(laxatives abuse, villous adenoma of the rectum)

Pathophysiological mechanisms • secretory diarrhea (increased intestinal secretion) ❖ infections (cholera toxin, E-col, salmonella, staphylococcal) ❖ Hormonal (Gut Hormones, ZES, VIP), cancer (calcitonin, Prostaglandins) ❖ miscellaneous (laxatives abuse, villous adenoma of the rectum) agents Adenylate cyclase cAMP system secretory diarrhea active NaCl

Pathophysiological mechanisms Osmotic diarrhea It caused by accumulation of the followings in the gut lumen being osmotically active poorly absorble solutes maldigestion of ingested food water failure to transport an osmotically diarrhea active dietary nonelectrolyte salts (E: glucose) intestinal lumen

Pathophysiological mechanisms • Osmotic diarrhea It caused by accumulation of the followings in the gut lumen water salts poorly absorble solutes maldigestion of ingested food failure to transport an osmotically active dietary nonelectrolyte (E: glucose) intestinal Lumen being osmotically active diarrhea

Colon Short-chain fatty acids Small Intestine Fluid Carbohydrates Protein Lipids lleum Fat-soluble vitamins Folate Bile acids Vitaronbn2 Calcium, phosphorus Iron Zinc

Causes of diarrhea in enteral nutrition Lumen Intestinal mucosa Excess volume Edema Osmotic load Disaccharidases or Formulas transport mechanisms Medication Atrophy Contamination Bacteria

Causes of diarrhea in enteral nutrition

Pathophysiological mechanisms Decreased intestinal surface area and/or intestinal absorption E: surgical removal; malabsorption syndrome

Pathophysiological mechanisms • Decreased intestinal surface area and/or intestinal absorption E: surgical removal; malabsorption syndrome

Pathophysiological mechanisms Rapid transit of intestinal contents(shortened transit time) increase in intestinal motility(intestinal hurry) contents reduce volume contact time->increase liquidity, stool small bowel mucosa E: irritable bowel syndrome [Functional diarrhea laxatives abuse post vagotomy diarrhea post gastrectomy dumbing syndrome

Pathophysiological mechanisms • Rapid transit of intestinal contents (shortened transit time) E: irritable bowel syndrome [Functional diarrhea] laxatives abuse post vagotomy diarrhea post gastrectomy dumbing syndrome stool volume liquidity contact time→ increase small bowel mucosa contents increase in intestinal motility (intestinal hurry) reduce

Calculation of osmotic gap 290 Unmeasured osmoles INcO □c 200 匚aK+ 匚Na+ E 100 0 Secretory diarrhea Osmotic diarrhea Osmotic gap 290 290 2X(Na+]+〖K+])=102X(Na+]+[K+])=230

Calculation of osmotic gap

Etiology Acute Diarrhea infection Food poisoning Systematic diseases(influenza, sepsis, measle, etc) Miscellanous

Etiology Acute Diarrhea • infection • Food poisoning • Systematic diseases (influenza, sepsis, measle, etc) • Miscellanous