Gastrointestinal Manifestations of Endocrine Disease

There are many complex interactions between the central and autonomic nervous systems and hypothalamus, pituitary, thyroid, parathyroid, and enteroendocrine cells in target gastrointestinal (GI) organs, which regulate food intake, metabolism, and GI motility. Current knowledge of hormonal influences between these different body systems is limited. Dysregulation of the thyroid gland can cause multiple effects on the upper and lower GI tract, the most common being abnormal intestinal motility (motor function) and transit time. Hyperparathyroidism can produce multiple manifestations including heartburn, nausea, abdominal pain, pancreatitis, and constipation as the most common manifestations. The most frequent complications of diabetes affecting the GI tract are gastroparesis and disturbance of pancreatic function. However, diabetes can also exacerbate existing periodontal disease and gastroesophageal disease. Celiac disease, hepatic microangiopathy, autoimmune gastritis, and the increased incidence of certain tumors (linked to insulin resistance) may also be regarded as long-term complications of diabetes. Adrenal insufficiency may be associated with nausea, anorexia, diarrhea, and abdominal pain and requires a high index of suspicion if no immediate cause for these symptoms is identified. Cushing’s syndrome may be a component of multiple endocrine neoplasia syndrome 1 (MEN 1), along with the Zollinger-Ellison syndrome which manifests as recurrent peptic ulcers. Endocrine disease may present with vague symptoms, particularly in older adults with age-related physiologic changes of the gastrointestinal (GI) tract and geriatric syndromes (frailty, sarcopenia, weight loss, and dementia). Underlying endocrine disease must be considered in the differential diagnosis, allowing for timely recognition and treatment.