Chapter+10+Diabetes+and+Metabolic+Syndrome.docx

Chapter 10: Diabetes and Metabolic Syndrome Diabetes Diabetes mellitus is caused by a deficit of insulin secretion from the beta cells of the pancreas OR lack of response to insulin (insulin resistance) Deficient insulin results in abnormal carbohydrate, protein, and fat metabolism because the trans...

Chapter 10: Diabetes and Metabolic Syndrome Diabetes Diabetes mellitus is caused by a deficit of insulin secretion from the beta cells of the pancreas OR lack of response to insulin (insulin resistance) Deficient insulin results in abnormal carbohydrate, protein, and fat metabolism because the transport of amino acids and glucose into cells is impaired. This causes a decline in protein synthesis and production of glycogen as well. Catabolism of fats and proteins leads to excessive amounts of fatty acids and their metabolites (ketones or ketoacids) in the blood Excessive amounts of ketones in blood cause ketoacidosis Ketoacids bind with bicarbonate buffer in blood which eventually decreased pH in body fluids Ketoacids are excreted in urine (ketonuria), some diabetic patients test their urine for ketones or glucose. (older generation called this a sugar test) Insulin is not required to transport glucose into the brain cells, which is good because neurons need a constant supply of glucose. Insulin is also not required for glucose absorption in the digestive tract. Exercising skeletal muscle can also utilize glucose without proportionate amounts of insulin This is important because excessive exercise can deplete the blood glucose level leading to hypoglycemia, but exercise is helpful in controlling blood glucose levels in the presence of an insulin deficit. Type I Diabetes Normal blood sugar (fasting) should be less than 100 mg/dL. Typically find Type I in children, but can occur in adults, sudden onset, autoimmune destruction, treat with insulin replacement. TYPE I is a major factor predisposing to strokes, heart attacks, peripheral vascular diseases, amputations, kidney failure, and blindness Results from a severe, absolute lack of insulin caused by destruction of islet cells in pancreas Before hyperglycemia occurs, 80-90% of insulin secreting beta cells of islet of Langerhans must be destroyed Beta cell abnormalities are present long before onset Beta cell and alpha cell abnormalities are present with a lack of insulin and an excess of glucagon Full metabolic syndrome is caused by both insulin deficiency and excess glucagon Type I affects metabolism of fat, protein and carbohydrate Excess glucose spills into urine as renal threshold is exceeded Other symptoms include polyuria (excess urine production), polydipsia (excess thirst), and polyphagia (excess hunger) (insert my story….) Ketoacidosis is caused by increased metabolism of fats and proteins resulting in high levels of circulating ketones pH drops, triggers buffering systems, acetone is blown off (results in sweet smelling breath) sometimes diabetic coma is the first symptom Complications of Acute Diabetes Mellitus Major acute complications of diabetes mellitus are hypoglycemia, diabetic ketoacidosis, and hyperosmolar hyperglycemic nonketotic syndrome Also may see Somogyi phenomenon and dawn phenomenon Hypoglycemia Low blood sugar occurs in more than 90% of cases Sometimes called insulin shock or insulin reaction Decrease blood glucose levels (45-60 mg/dl) and neurogenic reactions Pallor, tremor, anxiety, tachycardia, palpitations, diaphoresis (excessive sweating), headache, dizziness, irritability, fatigue, poor judgment, confusion, visual disturbances, hunger, seizures, coma Treat with immediate replacement of glucose (sugar under tongue is quick way) Diabetic ketoacidosis serious complication due to a deficiency of insulin and an increase in insulin counterregulatory hormones (catecholamines, cortisol, glucagon, growth hormone) Hepatic glucose production increases and peripheral glucose usage decreases Fat is mobilized and ketogenesis is stimulated The frequency of DKA peaks in adolescence Signs and symptoms include thirst, dry mouth, warm and dry skin, rapid, thready pulse, low blood pressure, decreased urine (oligouria), ketoacidosis leading to metabolic acidosis (leads to possible loss of consciousness) Treat by administering insulin and replacement of fluids and electrolytes (must give bicarbonate to reverse the acidosis) Hyperosmolar hyperglycemic nonketotic syndrome uncommon but significant complication of type II diabetes with a high mortality Occurs more often in elderly patients with comorbidities Poor glucose control leads to high serum osmotic pressures that lead to severe dehydration, low blood volume, low perfusion pressures Signs and symptoms include neurologic deficits, muscle weakness, speech difficulty, abnormal reflexes Somogyi effect is a unique combination of hypoglycemia followed by rebound hyperglycemia Rise in blood glucose is due to counterregulatory hormones (epinephrine, GH, corticosteroids) which are stimulated by hypoglycemia. Dawn phenomenon is an early morning rise in blood glucose levels with no hypoglycemia during the night, related to nighttime rise in GH which decreases metabolism of glucose by muscle and fat. Altering time and dose of insulin usually solves this. Chronic complications Vascular problems Microangiopathy causes thickening of capillary basement membranes resulting in rupture and tissue necrosis, loss of function (retinopathy is the leading cause of blindness) Macroangiopathy affects large arteries and leads to a high incidence of heart attacks, strokes, and peripheral vascular disease Obstruction in arteries of lower extremities result in ulcers (diabetic ulcers) and are slow to heal Stroke is twice as common in diabetics Peripheral neuropathy reduces pain and reduced blood flow creates gangrenous ulcers and infections (amputations likely) Neuropathy is common problem for diabetics Leads to impaired sensation, numbness, tingling, weakness, and muscle atrophy Results from ischemia and altered metabolic processes Infections are more common and more severe in diabetic patients Diabetics are susceptible to tuberculosis Candida infections (yeast) occur frequently in body folds (under breasts for example) Urinary tract infections are common Dental caries and periodontal disease are common Cataracts is another problem due to the abnormal metabolism of glucose Accumulated sorbitol and water in the lens destroys transparency Type II Diabetes Older adolescents and adults, insidious, obesity is a factor because insulin resistance is increased with obesity Treat with diet, exercise, hypoglycemic agents, insulin replacement if necessary Milder form of diabetes Increasing in adolescence and young adults, more are being diagnosed with metabolic syndrome Decreased beta cell responsiveness to plasma glucose and abnormal glucagon secretion This may be a decrease in beta cell mass, abnormal function of beta cells, or alterations of insulin receptor May see hyperinsulinemia as body tries to balance out excess blood glucose Often undiagnosed Goal of treatment is to restore normal glucose levels (euglycemia) and correct metabolic disorders Gestational diabetes Develops during pregnancy and usually resolves after pregnancy Larger birth weight for baby About 60 % of women who had this develop Type 2 within 15 years of pregnancy Obesity and Metabolic Syndrome Ability to burn fat during exercise declines after puberty Being overweight means that you have an excess amount of body weight that could include muscle, bone, fat, and water. Obesity means there is an excess amount of body fat. Overweight and obesity are due to a caloric imbalance This can be due to having more calories consumed than used, but can also be influenced by genetic, behavioral, and environmental factors. Can calculate body mass index (BMI) https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm The increase in obesity in the 6-11 years old age group has doubled between 1980 and 2000. The increase in obesity in 12-19 years old age group has tripled in that time. Along with this trend is a marked increase in type 2 diabetes, elevated cholesterol and increased blood pressure. Metabolic Syndrome: 3 factors are common to all varieties of this Increase in abdominal fat Changes in glucose metabolism (fasting blood sugar over 100 mg/dL) High blood sugar can cause darkening of skin under armpits, back, and sides of neck (acanthosis nigricans), blurred vision, excessive thirst, increased nocturnal urination, fatigue Changes in lipoprotein metabolism High triglycerides Low HDL Also includes high blood pressure Metabolic syndrome occurs in 1-4% of children and adolescents and a whopping 49% of clinically obese young people In the USA 1 out of ever 3 adults is diagnosed with metabolic syndrome Underlying cause of metabolic syndrome is the release of insulin antagonists by adipose tissue Insulin resistance is the main driver behind the syndrome An increased proportion of body fat results in insulin resistance in which the body’s cells become resistant to the effects of insulin and changes in metabolism. Diagnosis with lipid panel, BMP or basic metabolic panel, and a fasting glucose test Treatment involves changes in life style (food, exercise, sleep, stop smoking, stop stressing) and possible medications like metformin to lower blood sugar levels