All cause diarrhea except;
Diabetes
Hypercalcemia
Hypehyroidism
Irritable bowel syndrome
Hypercalcemia increases the tone of sphincters of the gut leading to refractory constipation. Autonomic dysfunction in diabetes explains the diarrhea. Due to sympathetic activity increase in thyrotoxicosis there is a reduction in small bowel transit time explaining the diarrhea. IBS has variable presentation between diarrhea and constipation
Malabsorbtion Syndrome