Diarrhea occurs when the bowel contains too much water, moves contents too quickly, fails to absorb nutrients or electrolytes properly, or becomes inflamed. 1. Secretory diarrhea Secretory diarrhea occurs when intestinal cells actively secrete chloride and water into the bowel lumen. This can happen with bacterial toxins, some viral infections, bile acid malabsorption, and some endocrine disorders. Secretory diarrhea often continues even when the patient is not eating. Clinical pattern: large-volume watery stool, dehydration risk, possible electrolyte loss. 2. Osmotic diarrhea Osmotic diarrhea occurs when poorly absorbed substances remain in the bowel and pull water into the lumen. Examples include lactose intolerance, sorbitol, magnesium-containing products, tube feeding intolerance, and malabsorption. Osmotic diarrhea often improves when the offending food, medication, or formula is stopped. Clinical pattern: watery stool, bloating, cramping, gas, relationship to intake. 3. Inflammatory diarrhea Inflammatory diarrhea occurs when the intestinal mucosa is damaged or ulcerated. This allows blood, mucus, serum proteins, and inflammatory cells to enter the stool. Causes include invasive bacterial infection, inflammatory bowel disease, ischemic colitis, radiation injury, and some severe medication reactions. Clinical pattern: fever,...