Rudy Bilous, MD, FRCP
Richard Donnelly, MD, PHD, FRCP, FRACP
Disordered gastrointestinal motor function occurs in both type 1 and type 2 diabetes and can result in symptoms of nausea, vomiting, diarrhea or constipation, malnutrition, poor glycemic control and delayed absorption of orally administered drugs (Figure 23.1). Gustatory sweating, typically affecting the head and neck, and postprandial hypotension may also occur. Traditionally, this has been attributed to irreversible autonomic neuropathy, but acute changes in blood glucose also play a role. For example, hyperglycemia delays gastric emptying by up to 15 minutes, slows gallbladder contraction and small intestinal transit, and inhibits colonic reflexes (Figure 23.2); while hypoglycemia accelerates gastric emptying (Figure 23.3). The mechanisms are unclear. Every effort to improve glycemic control should be made in symptomatic patients, including consideration of continuous subcutaneous insulin infusion (CSII).