MSEM112.pdf

11/20/23, 5:25 PM Realizeit for Student Type 1 Diabetes Type 1 diabetes is characterized by the destruction of the pancreatic beta cells (Norris, 2019). Combined genetic, immunologic, and possibly environmental (e.g., viral) factors are thought to contribute to beta-cell destruction. Although the...

11/20/23, 5:25 PM Realizeit for Student Type 1 Diabetes Type 1 diabetes is characterized by the destruction of the pancreatic beta cells (Norris, 2019). Combined genetic, immunologic, and possibly environmental (e.g., viral) factors are thought to contribute to beta-cell destruction. Although the events that lead to betacell destruction are not fully understood, it is generally accepted that a genetic susceptibility is a common underlying factor in the development of type 1 diabetes. People do not inherit type 1 diabetes itself but rather a genetic predisposition, or tendency, toward the development of type 1 diabetes. This genetic tendency has been found in people with certain human leukocyte antigen types. There is also evidence of an autoimmune response in type 1 diabetes. This is an abnormal response in which antibodies are directed against normal tissues of the body, responding to these tissues as if they were foreign. Autoantibodies against islet cells and against endogenous (internal) insulin have been detected in people at the time of diagnosis and even several years before the development of clinical signs of type 1 diabetes. In addition to genetic and immunologic components, environmental factors such as viruses or toxins that may initiate destruction of the beta cell continue to be investigated. Regardless of the specific cause, the destruction of the beta cells results in decreased insulin production, increased glucose production by the liver, and fasting hyperglycemia. In addition, glucose derived from food cannot be stored in the liver but instead remains in the bloodstream and contributes to postprandial (after meals) hyperglycemia. If the concentration of glucose in the blood exceeds the renal threshold for glucose, usually 180 to 200 mg/dL (9.9 to 11.1 mmol/L), the kidneys may not reabsorb all of the filtered glucose; glycosuria then occurs (i.e., the glucose then appears in the urine). When excess glucose is excreted in the urine, it is accompanied by excessive loss of fluids and electrolytes. This is called osmotic diuresis. Because insulin normally inhibits glycogenolysis and gluconeogenesis, these processes occur in an unrestrained fashion in people with insulin deficiency and contribute further to hyperglycemia. In addition, fat breakdown occurs, resulting in an increased production of ketone bodies, a highly acidic substance formed when the liver breaks down free fatty acids in the absence of insulin. Diabetic ketoacidosis (DKA) is a metabolic derangement that occurs most commonly in persons with type 1 diabetes and results from a deficiency of insulin; highly acidic ketone bodies are formed, and metabolic acidosis occurs. The three major metabolic derangements are hyperglycemia, ketosis, and metabolic acidosis (Norris, 2019). DKA is commonly preceded by a day or more of polyuria, polydipsia, nausea, vomiting, and https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IX2deLl%2f4FdfKSHmHSZ7peJYyAcbNSqCsVXJC0jIBoVz… 1/6 11/20/23, 5:25 PM Realizeit for Student fatigue with eventual stupor and coma if not treated. The breath has a characteristic fruity odor due to the presence of ketoacids. Type 2 Diabetes Type 2 diabetes occurs more commonly among people who are older than 30 years and who have obesity, although its incidence is rapidly increasing in younger people because of the growing epidemic of obesity in children, adolescents, and young adults (CDC, 2020). The two main problems related to insulin in type 2 diabetes are insulin resistance and impaired insulin secretion. Insulin resistance refers to a decreased tissue sensitivity to insulin. Normally, insulin binds to special receptors on cell surfaces and initiates a series of reactions involved in glucose metabolism. In type 2 diabetes, these intracellular reactions are diminished, making insulin less effective at stimulating glucose uptake by the tissues and at regulating glucose release by the liver (see Fig. 46-1). The exact mechanisms that lead to insulin resistance and impaired insulin secretion in type 2 diabetes are unknown, although genetic factors are thought to play a role. To overcome insulin resistance and to prevent the buildup of glucose in the blood, increased amounts of insulin must be secreted to maintain the glucose level at a normal or slightly elevated level. If the beta cells cannot keep up with the increased demand for insulin, the glucose level rises and type 2 diabetes develops. Insulin resistance may also lead to metabolic syndrome, which is a constellation of symptoms, including hypertension, hypercholesterolemia, abdominal obesity, and other abnormities (Norris, 2019). Despite the impaired insulin secretion that is characteristic of type 2 diabetes, there is enough insulin present to prevent the breakdown of fat and the accompanying production of ketone bodies. Therefore, DKA does not typically occur in type 2 diabetes. However, uncontrolled type 2 diabetes may lead to another acute problem— hyperglycemic hyperosmolar syndrome (HHS). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IX2deLl%2f4FdfKSHmHSZ7peJYyAcbNSqCsVXJC0jIBoVz… 2/6 11/20/23, 5:25 PM Realizeit for Student Because type 2 diabetes is associated with a slow, progressive glucose intolerance, its onset may go undetected for many years. If the patient experiences symptoms, they are frequently mild and may include fatigue, irritability, polyuria, polydipsia, poorly healing skin wounds, vaginal infections, or blurred vision (if glucose levels are very high). For most patients (approximately 75%), type 2 diabetes is detected incidentally (e.g., when routine laboratory tests or ophthalmoscopic examinations are performed). One consequence of undetected diabetes is that long-term diabetes complications (e.g., eye disease, peripheral neuropathy, peripheral vascular disease) may have developed before the actual diagnosis of diabetes is made (ADA, 2020), signifying that the blood glucose has been elevated for a time before diagnosis. https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IX2deLl%2f4FdfKSHmHSZ7peJYyAcbNSqCsVXJC0jIBoVz… 3/6 11/20/23, 5:25 PM Realizeit for Student Gestational Diabetes Gestational diabetes is any degree of glucose intolerance with its onset during pregnancy (Norris, 2019). Hyperglycemia develops during pregnancy, particularly in the second and third trimesters, because of the secretion of placental hormones that cause insulin resistance. Women who are considered to be at high risk for gestational diabetes and should be screened by blood glucose testing at their first prenatal visit are those with marked obesity, a personal history of gestational diabetes, glycosuria, or a strong family history of diabetes. High-risk ethnic groups include Hispanic Americans, Native Americans, Asian Americans, African Americans, and Pacific Islanders. If these high-risk women do not have gestational diabetes at initial screening, they should be retested between 24 and 28 weeks of gestation. All women of average risk should be tested at 24 to 28 weeks of gestation. Testing is not specifically recommended for women identified as being at low risk. Low-risk women are those who meet all of the following criteria: age younger than 25 years, normal weight before pregnancy, member of an ethnic group with low prevalence of gestational diabetes, no history of abnormal glucose tolerance, no known history of diabetes in first-degree relatives, and no history of poor obstetric outcomes (ADA, 2020). Women considered to be at high or average risk should have either an oral glucose tolerance test or a glucose challenge test followed by an oral glucose tolerance test in women who exceed the glucose threshold value of 140 mg/dL (7.8 mmol/L) (ADA, 2020). Initial management includes dietary modification and blood glucose monitoring. Between 70% and 85% of women with gestational diabetes can control blood glucose levels with lifestyle modifications alone. Dietary recommendations include a daily minimum of 175 g of carbohydrates, 71-g protein, 28-g fiber, and low saturated fats (ADA, 2020). If hyperglycemia persists, insulin is prescribed. Target ranges for blood glucose levels during pregnancy are 140 to 180 mg/dL (7.8 to 10 mmol/L) (ADA, 2020). After delivery, blood glucose levels in women with gestational diabetes usually return to normal. However, many women who have had gestational diabetes develop type 2 diabetes later in life. Women with a history of gestational diabetes should be screened for the development of diabetes or prediabetes every 3 years (ADA, 2020). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IX2deLl%2f4FdfKSHmHSZ7peJYyAcbNSqCsVXJC0jIBoVz… 4/6 11/20/23, 5:25 PM Realizeit for Student https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IX2deLl%2f4FdfKSHmHSZ7peJYyAcbNSqCsVXJC0jIBoVz… 5/6 11/20/23, 5:25 PM Realizeit for Student Example https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IX2deLl%2f4FdfKSHmHSZ7peJYyAcbNSqCsVXJC0jIBoVz… 6/6