Notes on Diabetes Mellitus

Introduction to Diabetes Mellitus

• Diabetes mellitus characterized by high blood glucose levels.
• Body struggles to move glucose from blood into cells, leading to energy starvation.
• Important hormones: insulin (lowers blood glucose) and glucagon (raises blood glucose).
• Both are produced in the pancreas by islets of Langerhans.

Hormonal Control of Blood Glucose

• Insulin:
  • Secreted by beta cells (center of islets).
  • Binds to insulin receptors on muscle and adipose tissues, promoting glucose uptake.
• Glucagon:
  • Secreted by alpha cells (periphery of islets).
  • Stimulates liver to generate glucose from glycogen and other molecules.

Types of Diabetes Mellitus

• Type 1 Diabetes:
  • Accounts for 10% of diabetes cases.
  • Autoimmune destruction of beta cells in the pancreas due to T cell attack.
  • Loss of self-tolerance leads to immune response against beta-cell antigens.
  • Symptoms include polyphagia, glycosuria, polyuria, and polydipsia.

Clinical Symptoms of Type 1 Diabetes

1. Polyphagia: Increased hunger due to energy starvation.
2. Glycosuria: Glucose spilling into urine because of high blood glucose.
3. Polyuria: Increased urination triggered by osmotic effects of glucose.
4. Polydipsia: Excessive thirst resulting from dehydration.

Diabetic Ketoacidosis (DKA)

• Occurs when the body breaks down fat for energy, producing ketone bodies.

• Increased acidity in blood due to ketoacids leads to symptoms like:

  • Kussmaul respiration (deep, labored breathing).
  • Hyperkalemia (high potassium levels due to insulin deficiency).
  • High anion gap due to ketoacid accumulation.

• Treatment involves hydration, insulin therapy, and electrolyte replacement.

• Type 2 Diabetes:

  • Represents 90% of diabetes cases; body produces insulin but tissues are insulin resistant.
  • Risk factors include obesity, inactivity, and hypertension.
  • Mechanisms include inflammation related to excess adipose tissue.

Insulin Resistance in Type 2 Diabetes

• Beta cell hyperplasia and hypertrophy initially compensate for insulin resistance.
• Over time, beta cell function declines, leading to hyperglycemia.
• Symptoms similar to Type 1 diabetes but generally no DKA.
• Complication: Hyperosmolar Hyperglycemic State (HHS) due to extreme dehydration.

Other Types of Diabetes Mellitus

• Gestational Diabetes: Increased blood glucose during pregnancy.
• Drug-induced Diabetes: Resulting from medication side effects.

Diagnosis of Diabetes

• Common tests:
  • Fasting Glucose Test: 126 mg/dL or higher indicates diabetes.
  • Oral Glucose Tolerance Test: 200 mg/dL or higher indicates diabetes.
  • HbA1c Test: 6.5% or higher reflects long-term glucose levels.
  • C-peptide Test: Low levels indicate insufficient insulin production.

Treatment Options

• Type 1 Diabetes: Requires lifelong insulin therapy.
• Type 2 Diabetes: Treated with lifestyle changes, oral medications (e.g., metformin), and possibly insulin.
• Risk of hypoglycemia with insulin treatment; symptoms range from weakness to loss of consciousness.

Complications of Uncontrolled Diabetes

• Microvascular Damage: Leads to retinopathy, nephropathy, and neuropathy.
• Macrovascular Damage: Increases risk for atherosclerosis, heart attacks, and strokes.
• Importance of blood sugar control through healthy lifestyle and medications.

Conclusion

• Type 1 diabetes cannot be prevented; type 2 diabetes can often be managed and controlled.
• Many individuals with diabetes can effectively live full lives through proper management.