All cause diarrhea except;
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
Diabetes
Hypercalcemia
Hypehyroidism
Irritable bowel syndrome
Malabsorbtion Syndrome