What is the basic mechanism of all diarrheal diseases?
- Diarrhea is due to the incomplete absorption of fluid from luminal contents.
- Normal stools are approximately 75% water and 25% solids. Normal fecal water output is approximately 60 to 80 mL per day.
- An increase of fecal water output of 50 to 100 mL is sufficient to cause loosening of the stool.
- This volume represents approximately 1% of the fluid load entering the upper intestine each day; thus malabsorption of only 1% to 2% of fluid entering the intestine may be sufficient to cause diarrhea
