NUR246 TOPIC 4 LECTURE

Endocrine: Diabetes Type 2 Lecture Notes

Prevalence of Diabetes

  • More than 6% of the population are affected, approximately:

    • 260,000 people in New Zealand.

    • 1,200,000 people in Australia.

  • Rising prevalence rate of around 7% per year.

  • Rates of diabetes are 4 times higher for Aborigines and Torres Strait Islander people, with 86% having type 2 diabetes.

  • Prevalence has doubled in the last 20 years.

  • 16.4% of the population is estimated to have pre-diabetes.

Definition of Diabetes Mellitus

Diabetes mellitus encompasses a group of metabolic diseases characterized by high levels of blood glucose over prolonged periods, which may lead to:

  • Insulin deficiency: This may include insufficient or no release of insulin by the islets of Langerhans.

  • Insulin resistance: This indicates an ineffective response to insulin at target cells.

Risk Factors for Developing Type 2 Diabetes

Several factors contribute to the risk of developing type 2 diabetes, including:

  • Obesity: Increased Body Mass Index (BMI) is a primary risk factor.

  • Pre-diabetes: A significant predictor of future diabetes.

  • Metabolic syndrome: A cluster of conditions that increase the risk of heart disease, stroke, and diabetes.

  • Physical inactivity: A sedentary lifestyle is linked to an increased risk.

  • Unhealthy diet: Diets high in sugars and fats can contribute significantly to diabetes risk.

  • Tobacco smoking: Associated with an increased risk for type 2 diabetes.

  • Genetic factors: A family history of diabetes can predispose individuals to developing the condition.

Classification and Characteristics of Diabetes

Types of Diabetes

  • Type 1 Diabetes:

    • Long preclinical period with abrupt onset of clinical manifestations.

    • Prone to hypoglycemia and ketoacidosis.

    • Insulin-dependent, requiring frequent adjustments in insulin doses.

    • Primarily autoimmune and genetically driven.

    • Affects mostly younger individuals around puberty but can occur at any age.

  • Type 2 Diabetes:

    • Generally shows gradual onset unlike Type 1.

    • Initially responds well to oral agents but may progress to insulin treatment.

    • Strongly correlated with obesity and generally occurs in individuals over 35 years of age.

  • Gestational Diabetes:

    • Glucose intolerance recognized during pregnancy, especially in the third trimester.

    • Treatment includes dietary management, and 40% of women may need insulin treatment.

    • After childbirth, glucose levels may normalize but can also progress to diabetes.

    • Occurs in 2% of all pregnancies with a 60% chance of developing diabetes within 15 years.

Pathophysiology of Type 2 Diabetes

Diabetes Type 2 is characterized by a complex interplay of hyperglycemia and insulin resistance:

  1. Hyperglycemia stimulates the pancreas to secrete insulin.

  2. Insulin binds to receptors on target cells but the response is inadequate due to decreased insulin sensitivity.

  3. Elevated glucose levels persist, prompting further insulin secretion which ultimately leads to a cycle of continued hyperglycemia.

  4. Over time, this can result in a decreased number of insulin receptors on target cells, exacerbating glucose intolerance.

  5. Insufficient glucose transported into cells leads to elevated blood glucose levels which continue to prompt insulin secretion.

Diagnosis of Diabetes

Diagnosing diabetes involves assessing abnormal test results:

  • Fasting blood glucose: ≥ 7.0 mmol/L.

  • Random blood glucose: ≥ 11.1 mmol/L.

  • HbA1c levels: > 6.5%.

Oral Glucose Tolerance Test (OGTT)

Plasma glucose levels (in mmol/L) are measured at two points:

  • Fasting Plasma Glucose (mmol/L):

    • Normal: < 6.1

    • Impaired fasting glucose: 6.1-6.9

    • Diabetes: ≥ 7.0

  • 2 Hours Following Glucose Ingestion:

    • Normal: < 7.8

    • Impaired glucose tolerance: 7.8-11.0

    • Diabetes: ≥ 11.1

Monitoring Blood Glucose Levels

  • Blood glucose monitors: Indicate short-term blood glucose, checked at least once a day.

  • HbA1c: Reflects long-term glucose control and reported in percentage or mmol/mol.

Clinical Manifestations and Mechanisms of Type 2 Diabetes

Common Manifestations

  • Recurrent infections: Skin infections, prolonged wound healing.

  • Genital pruritus: Often due to hyperglycemia.

  • Visual changes: Blurred vision potentially leading to diabetic retinopathy.

  • Paraesthesias: Abnormal sensations due to neuropathy.

  • Fatigue: Related to metabolic changes.

Mechanisms Behind these Manifestations

  1. Increased glucose levels stimulate the growth of microorganisms, contributing to infections.

  2. Hyperglycemia often leads to fungal growth, particularly in candidal infections, causing pruritus.

  3. Visual disturbances arise from fluctuating water balance in the eyes due to elevated glucose.

  4. Neuropathy results from metabolic and vascular changes leading to nerve degeneration.

  5. Metabolic changes hinder nutrient utilization, contributing to fatigue.

Complications of Diabetes

Chronic Complications

  • Microvascular disease: Affects small capillaries leading to neuropathy, nephropathy, and retinopathy.

  • Macrovascular disease: Involves larger vessels and increases risks for strokes and heart disease.

  • Neuropathy: Can lead to impotence, urinary incontinence, and lower extremity complications.

Acute Complications

  • Hypoglycemia

  • Diabetic ketoacidosis

  • Hyperglycemic hyperosmolar state

Pharmacological Management of Type 2 Diabetes

  • First-line medications:

    • Metformin: Cornerstone of treatment, effective, and carries cardiovascular benefits without causing weight gain.

    • Sulfonylureas: Such as glibenclamide, carry risks of hypoglycemia and weight gain.

    • DPP-4 Inhibitors: E.g., sitagliptin, are well-tolerated and often used alongside metformin.

  • Other glucose-lowering medications:

    • Insulin formulations (various types) and SGLT2 inhibitors (e.g., empagliflozin).

Nutritional Therapy for Diabetes

  • Type 1 Diabetes: Increased energy intake to achieve and maintain body weight; consistent distribution of carbohydrates.

  • Type 2 Diabetes: Reduction in overall caloric intake; dietary considerations may vary depending on the individual medication regimen.

Monitoring for Long-term Complications

  • Regular screenings for retinopathy, nephropathy, and neuropathy are essential.

  • Key risk factors include hypertension, dyslipidaemia, and family history of diabetes complications.

HbA1C:

  • What it is: A blood test that shows the average blood glucose level over the past 2–3 months.

  • How often: Checked every 3–6 months.

  • Normal range: Below 6.5% (or <48 mmol/mol).

  • If high: It means long-term blood glucose levels are not well controlled, increasing risk for complications like neuropathy, kidney disease, and retinopathy.

Blood Glucose Monitoring (BGL):

  • What it is: A finger-prick test showing short-term (current) blood glucose levels.

  • Normal range:

    • Fasting: <6.1 mmol/L

    • 2 hours after eating: <7.8 mmol/L

  • Why keep a diary: Helps track daily readings, see how food, medication, and exercise affect glucose levels, and guide treatment adjustments.

Patterns/Trends to Look For & When to Get Help:

  • Watch for consistently high or low readings, or large fluctuations.

  • Seek help if readings are frequently >11 mmol/L or <4 mmol/L, or if symptoms like dizziness, sweating, or excessive thirst occur.

Recommended Times to Check BGL:

  • Before meals, 2 hours after meals, before bed, and occasionally overnight if advised by the healthcare team.

Tips to Prevent Sore Fingers:

  • Rotate fingers, use sides of fingertips (not the centre), use warm water before testing, and change lancets regularly.

Blood Pressure and Diabetes:

  • High blood pressure damages blood vessels and increases the risk of stroke, heart disease, and kidney damage.

  • Regular monitoring helps prevent macrovascular and microvascular complications.

LDL (Low-Density Lipoprotein):

  • Known as “bad cholesterol.”

  • High LDL contributes to artery blockages and increases risk of heart disease—a major complication of diabetes.

  • Managing LDL with diet, exercise, and medication helps protect the heart and blood vessels.

What is Hypoglycaemia?

  • Low blood glucose level (<4 mmol/L).

  • Occurs when there is too much insulin or too little glucose in the blood.

Symptoms:

  • Sweating, shakiness, hunger, dizziness, confusion, blurred vision, headache, irritability, and in severe cases, loss of consciousness.

What is Hyperglycaemia?

  • High blood glucose level (>11 mmol/L).

  • Caused by insufficient insulin, insulin resistance, or excess glucose intake.

Symptoms:

  • Thirst, frequent urination, fatigue, blurred vision, dry mouth, and slow-healing wounds.

Pathophysiology:

  • When BGL is high: The pancreas releases insulin to help glucose enter cells. In Type 2 Diabetes, the cells are insulin resistant, so glucose stays in the blood → hyperglycaemia.

  • When BGL is low: The pancreas releases glucagon to signal the liver to release stored glucose. If there’s too much insulin or not enough food, blood sugar drops → hypoglycaemia.

Best Treatment for Hypoglycaemia:

  • Give 15–20g of fast-acting carbohydrate (e.g. juice, glucose tablets, or jellybeans).

  • Recheck BGL after 10–15 minutes and repeat if still low.

  • Follow up with a longer-acting carbohydrate snack (e.g. sandwich or milk).

Role of the Diabetic Specialist Nurse:

  • Educates on blood glucose monitoring, diet, insulin use, and managing hypo/hyperglycaemia.

  • Supports medication adjustments and lifestyle management.

  • Provides ongoing education to prevent complications.

Potential Complications:

  • Short-term: Hypoglycaemia, hyperglycaemia, diabetic ketoacidosis (DKA), and hyperglycaemic hyperosmolar state.

  • Long-term:

    • Microvascular: Retinopathy, nephropathy, neuropathy.

    • Macrovascular: Stroke, heart disease, peripheral vascular disease.

Healthy Diabetic Diet:

  • Focus on balanced meals with whole grains, lean proteins, healthy fats, fruits, and plenty of vegetables.

  • Choose low-GI (glycaemic index) foods to maintain steady blood glucose levels.

  • Limit added sugars, processed foods, and saturated fats.

  • Eat regular meals to prevent large BGL fluctuations.

Myths About What Diabetics Can’t Eat:

  • Myth: Diabetics can’t eat sugar at all.
    Fact: Small amounts of sugar can be included as part of a balanced diet.

  • Myth: Diabetics must eat special “diabetic” foods.
    Fact: Regular healthy foods are suitable—no need for “diabetic” products.

  • Myth: Carbs should be avoided.
    Fact: Carbohydrates are important but should come from whole grains and high-fibre sources.

Why They Should Adapt Their Diet:

  • Helps control blood glucose levels.

  • Prevents weight gain and improves insulin sensitivity.

  • Reduces risk of heart disease, stroke, and other diabetic complications.

Complications of Being Overweight and Diabetic:

  • Increased insulin resistance, making glucose control harder.

  • Higher risk of cardiovascular disease, hypertension, and high cholesterol.

  • Greater likelihood of nerve, kidney, and eye damage over time.

Role of the Dietitian:

  • Provides individualised meal plans based on weight, medications, and lifestyle.

  • Educates on carbohydrate counting and portion control.

  • Supports healthy weight management and sustainable eating habits.

  • Works alongside the diabetes care team to optimise nutrition and glucose control.