Osmotic diarrhea

Osmotic diarrhea

• Watery diarrhea - A condition characterized by frequent loose or watery stools, indicating an increased fluid content in the intestine.

• Decreased fecal fat - Low levels of fat in the feces, which can indicate a problem with the absorption of fat in the small intestine, such as Crohn’s disease, cystic fibrosis, or other conditions.

• Increased osmotic gap - A laboratory value that measures the concentration of substances in the stool that can cause water retention, such as undigested carbohydrates. An increased osmotic gap can indicate osmotic diarrhea, where the intestine is not able to absorb water normally.

• Decreased diarrhea with fasting - A decrease in the frequency or severity of diarrhea symptoms when the patient is not eating, which can indicate that the cause of the diarrhea is related to food or digestive issues.

• dairreha caused by ingestion of poorly absorbed cations or anions (Mg, sulfate, phos; found in laxatives) or poorly absorbed carbs (eg, mannitol, sorbitol [found in chewing gum]) or lactose if lactose intolerant. Diarrhea resolves w/ cessation of offending substance.

• Dx: ↑ stool osmotic gap (see Figure); stool pH <6 if unabsorbed carbohydrates

• Lactose intolerance: can be acquired after gastroenteritis, med illness, GI surg. Clin: bloating, flatulence, discomfort, diarrhea. Dx: H+ breath test or empiric lactose-free diet. Rx: lactose-free diet & lactase tablets.