CHAPTER 49 Diabetes Mellitus
1 Describe the principal types of diabetes mellitus
Type 1 diabetes mellitus: An autoimmune disorder in which destruction of the pancreatic islet cells results in the inability to produce insulin. Onset is more common in children and young adults.
Type 2 diabetes mellitus: A disorder in the body’s ability to use insulin. Early in the course of the disease the patient may be able to make sufficient insulin, but cell-receptor impairment results in hyperglycemia despite normal or high insulin levels. Type 2 diabetes is usually a disease of older adults; onset in the sixth decade and beyond is common. As obesity increases in the population type 2 diabetes also increases. Type 2 diabetes is now commonly seen in adolescents and young adults with obesity and a sedentary lifestyle.
3 What comorbidities are frequently observed in patients with diabetes mellitus and to what significance?
Hypertension is seen in 40% of patients with poorly controlled diabetes who undergo surgery. Hypertension is a risk factor for coronary artery disease and cardiac failure. If these patients are treated with potassium-wasting diuretic agents, there is often significant total body loss of potassium.
Coronary artery disease is common, occurs in younger patients, and may be silent or present atypically.
Autonomic neuropathy may compromise neuroreflexic control of cardiovascular and gastrointestinal function, manifesting as orthostatic hypotension, gastroparesis (increased risk of aspiration), ileus, and urinary retention. Peripheral neuropathies are common.
Disturbances in renal function are common, including increased blood urea nitrogen (BUN) and creatinine, protein loss, hypoalbuminemia, acidosis, and electrolyte disturbances.
4 What oral medications are currently used in type 2 diabetes?
There are two categories of drugs used in treating type 2 diabetes: those that enhance the effectiveness of insulin and those that increase the supply of insulin to the cells. These drugs are outlined in Table 49-1.
5 What insulins are in current use?
Modern intensive insulin therapy relies on newly designed insulin analogs. Insulin therapy is given using a basal-bolus construct: long-acting (24-hour) insulin is used to provide a steady basal platform, and rapid-acting insulin is used to provide boluses for carbohydrate intake in meals and snacks. This necessitates giving at least four injections per day or the use of an insulin pump. The specific insulins are outlined in Table 49-1.