Hormonal Imbalances Causing Chronic Diarrhea

Primary Endocrine Causes

The American Gastroenterological Association recommends that thyroid-stimulating hormone (TSH) should be measured in all patients with chronic diarrhea, as a suppressed TSH is the best predictor for hyperthyroidism 1
Hyperthyroidism causes diarrhea through direct endocrine effects on gut motility, accelerating intestinal transit time and producing both secretory diarrhea and steatorrhea, according to the European Society of Endocrinology 2
The combination of autonomic neuropathy and altered bile acid metabolism creates a particularly challenging clinical picture in diabetic patients, as stated by the American Diabetes Association 1
Hypoparathyroid disease and adrenal disease predispose to diarrhea through endocrine effects and autonomic dysfunction, as noted by the Endocrine Society 1

The American College of Gastroenterology recommends that thyroid function tests (TSH) should be performed routinely in all patients with chronic diarrhea 1
Complete blood count, comprehensive metabolic panel, and inflammatory markers (ESR, CRP) should be obtained, as abnormalities have high specificity for organic disease, according to the American Gastroenterological Association 1, 2
Fasting glucose or HbA1c to screen for diabetes mellitus, as recommended by the American Diabetes Association 2

Nocturnal diarrhea essentially rules out functional disorders and mandates investigation for organic disease including endocrine causes, as stated by the European Society of Gastroenterology 2
Diabetic diarrhea is often multifactorial—consider bacterial overgrowth, bile acid malabsorption, and medication effects (metformin) rather than attributing symptoms solely to autonomic neuropathy, according to the American Diabetes Association 1, 2