Chapter 59: Diabetes Mellitus

Diabetes mellitus represents a metabolic syndrome characterized by elevated blood glucose resulting from insufficient insulin production, impaired insulin function, or both. Type 1 diabetes develops through autoimmune destruction of pancreatic beta cells, typically in younger individuals, and manifests with classic symptoms including excessive urination, increased thirst, increased hunger, and unexplained weight loss. This form requires lifelong insulin replacement therapy administered through injections or continuous delivery systems, alongside rigorous glucose monitoring protocols. Type 2 diabetes, the most prevalent form, stems from a combination of insulin resistance and progressive beta cell dysfunction, strongly associated with obesity and sedentary lifestyle patterns. Management emphasizes lifestyle modification including weight reduction, dietary approaches such as Mediterranean or DASH patterns, regular aerobic activity, and pharmacological intervention beginning with metformin as the preferred first-line agent, with additional options including agents that enhance insulin secretion or alter glucose handling through renal mechanisms. Type 3c diabetes emerges from underlying exocrine pancreatic pathology such as chronic inflammation, cystic fibrosis, or traumatic injury, creating brittle glycemic control due to simultaneous loss of both insulin and counter-regulatory hormones. The disease produces both immediate life-threatening complications including diabetic ketoacidosis in type 1 presentations and hyperosmolar hyperglycemic emergencies in type 2 disease, as well as long-term vascular and neurological damage affecting vision, kidney function, and peripheral sensation. Diagnostic confirmation utilizes hemoglobin A1c measurement, fasting glucose determination, or random glucose with symptomatology. Comprehensive management requires regular monitoring through A1c assessment, ophthalmologic screening, foot examination protocols, and kidney function assessment, with acute hypoglycemia managed through rapid carbohydrate consumption and severe episodes reversed with glucagon or intravenous dextrose administration.