Diabetes Mellitus Part 1 Kathy Martin DNP, RN, CNE

Definition  Characterized by elevated levels of glucose in the blood (hyperglycemia)  Affects many body systems and has major physical, social, and economic consequences:  The leading cause of nontraumatic amputations, blindness in working-age adults, and end-stage renal disease  Affects nearly 24 million people in the United States (8%) especially those over 60.  1/3 are undiagnosed  Costs related to diabetes are estimated to be $174 billion annually

Classification of DM Type 1 diabetes: Characterized by destruction of the pancreatic beta cells Results in decreased insulin production, unchecked glucose production by the liver, and fasting hyperglycemia Type 2 diabetes: Main problems are insulin resistance and impaired insulin secretion Gestational diabetes mellitus (GDM) is any degree of glucose intolerance with onset during pregnancy

Both types lead to Hyperglycemia Fasting blood glucose > 126 mg/dL

Risk Factors Family history of diabetes Obesity (ie, BMI ≥25 kg/m 2 ) Ethnicity (eg, African Americans, Latino, Native American, Asian American, Pacific Islanders) Age ≥45 years Previous impaired glucose tolerance fasting glucose Hypertension (≥140/90 mm Hg) Low HDL cholesterol level ( 250 mg/dL) History of gestational diabetes or delivery of babies over 9 pounds

Functions of Insulin Hormone released by beta cells of islets of Langerhans in pancreas Released in pulsatile increments in response to rising serum glucose Insulin lowers serum glucose and stimulates cellular metabolism Maintains normal serum glucose – 70 to 120 mg/dl Promotes glucose transport from blood across cell membrane to cell cytoplasm (skeletal muscle and adipose tissue) Stimulates storage of glucose as glycogen in liver and muscle Enhances fat deposition Inhibits protein degradation Accelerates the process of amino acid transport into cells and protein synthesis

Insulin Secretion by the Pancreas

Effect of insulin on glucose uptake and metabolism. Insulin binds to its receptor (1) which in turn starts many protein activation cascades (2). These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5) and fatty acid synthesis (6).plasma membraneglycogenglycolysisfatty acid

Counter-regulatory hormones Glucagon, epinephrine, growth hormone, cortisol and somatostatin work to counter the effects of insulin These hormones increase blood glucose during sleep and periods of fasting

Type 1 Diabetes Mellitus See - Classification of Diabetes Mellitus May be caused by autoimmune destruction of ß cells secondary to genetic predisposition and/or other factors (? viral) No insulin  increased circulating glucose  serum becomes hyperosmolar Osmotic effects of hyperglycemia – 3 P’s Polyuria – excessive urination Polydipsia – excessive thirst Polyphagia – excessive hunger Osmotic diuresis  (cellular) dehydration, loss of electrolytes esp. K, glucosuria Protein breakdown  gluconeogenesis (glucose is formed from non-carbohydrate sources)  weight loss,  blood nitrogen (BUN) Body cells cannot utilize glucose  fat breakdown  ketone produced (acidic, ketonuria)  metabolic acidosis  DKA DKA (metabolic acidosis)  N & V, Kussmaul respirations (deep, rapid), fruity breath, renal failure, hypovolemic shock, coma, death

Type 1 Diabetes Mellitus Signs and Symptoms Clinical symptoms - Rapid onset “3 P’s” Blurred vision Children - nocturnal enuresis Ketosis (fruity breath), hyperglycemia

Prediabetes Impaired fasting glucose or impaired glucose tolerance Fasting glucose levels mg/dL OGTT mg/dL Usually develop Type 2 diabetes Long-term complications may start in this phase

Type 2 Diabetes Mellitus 90% of those with diabetes have Type 2 80% are overweight Strong genetic factor  prevalence with age, Native American, Hispanic, African American

Type 2 Diabetes Mellitus Major metabolic abnormalities in Type 2 DM: Insulin resistance Hyperglycemia ensues Hyperinsulinemia Impaired glucose tolerance Blood glucose regulation abnormal (prediabetes) Pancreas looses ability to produce insulin Eventual beta cell exhaustion Inappropriate glucose production by liver Production of hormones by adipose tissue Metabolic syndrome: high TG, high LDL, low HDL, hypertension

Type 2 Diabetes Mellitus Signs & Symptoms Slow onset – months/years Blurred vision Fatigue Poor wound healing Prone to infections 3 P’s not as pronounced Client adjusts to symptoms – denial !!