Since diabetes mellitus affects every organic system, it affects gastrointestinal tract as well. The precise extent of digestive disorders associated with diabetes mellitus is unknown. Few mechanisms may lead to these manifestations including autonomic neuropathy, diabetic microangiopathy, poor glycemic regulation, altered production of glucagon and insulin, and increased susceptibility to gastrointestinal infections. Esophageal disorders like reduced amplitude of esophageal contractions, reduced lower esophageal sphincter pressure, and abnormal acid reflux occur commonly in patients with diabetes mellitus. Diabetes is included in a certain number of stomach disorders and is considered responsible for undefined dyspeptic symptoms.
In oposite to manifestations in the stomach which are usually asymptomatic, manifestations on small intestine related to diabetes are much more symptomatic. Diarrhoea and steatorrhea are frequent among diabetics. Obstipation is probably the most common gastrointestinal symptom in patients with diabetes. Obstipation an be an extension of diabetic diarrhoea, which happens more often, or it can, less frequently, precede diarrhoea, but it can exist independently of any kind of digestive disorders, particularly in older diabetics. In patients who suffer from diabetes there is a complex relation between exocrine and endocrine pancreas component: pancreatitis can produce diabetes, and diabetes is often associated with deteriorated exocrine pancreas secretion.
Common complication of diabetes mellitus is fatty liver. Diabetes mellitus and liver cirrhosis are often associated. Diabetes may precede or be the cause of cirrhosis of the liver and vice versa, cirrhosis of the liver may precede or cause diabetes. There is an unexplained higher incidence of gall stones in patients with diabetes mellitus. Adequate and urgent recognition of gastrointestinal manifestations of diabetes mellitus is important for treatment of these patients.