metabolism

DIABETES

Overview of Diabetes

  • Definition: Chronic multisystem disease characterized by hyperglycemia related to abnormal insulin production, impaired insulin use, or both.

  • Prevalence:
      - Affects an estimated 34.2 million people in the United States.
      - 88 million have prediabetes.
      - 17.3 million are unaware of their condition.
      - Diabetes is the 7th leading cause of death.

Etiology and Pathophysiology

  • Causes: Diabetes may stem from a
      - Genetic factor.
      - Autoimmune reaction.
      - Environmental influences.

  • Pathophysiology: Primarily a disorder of glucose metabolism related to absent or insufficient insulin and/or ineffective use of available insulin.

Classification of Diabetes

  • Type 1 Diabetes Mellitus (T1DM):
      - Formerly known as juvenile diabetes or insulin-dependent diabetes mellitus (IDDM).
      - Characteristics:
        - Typically diagnosed in younger patients, often before age 15.
        - Autoimmune disorder; familial and lifelong.
        - Insulin production is absent or minimal.
        - Prone to ketoacidosis.

  • Type 2 Diabetes Mellitus (T2DM):
      - Also known as non-insulin-dependent diabetes mellitus (NIDDM).
      - Characteristics:
        - More common in adults over 40.
        - Often associated with obesity and insufficient insulin production.
        - Ketoacidosis is not common.
        - May require insulin based on disease progression.

  • Gestational Diabetes: Develops during pregnancy, often resolves postpartum but increases the risk of developing type 2 diabetes.

  • Maturity Onset Diabetes of the Young (MODY): A rare form of diabetes due to a genetic defect, occurs in adolescence or early adulthood.

Assessment of Diabetes

  • Common Symptoms:
      - Weight loss (typical in T1DM).
      - Increased thirst (polydipsia).
      - Increased hunger (polyphagia).
      - Frequent urination (polyuria).
      - Fatigue.
      - Blurry vision.
      - Numb or tingling hands or feet.
      - Slow healing wounds and infections.

  • Additional Assessment:
      - Diagnosis confirmed by fasting blood glucose (FBG) ≥ 126 mg/dl or casual glucose ≥ 200 mg/dl plus symptoms.
      - Hemoglobin A1C test indicating average blood sugar levels over the past two to three months.

Complications of Diabetes

  • Major Complications:
      - Microvascular complications:
        - Diabetic retinopathy.
        - Diabetic nephropathy.
        - Diabetic neuropathy.
      - Macrovascular complications:
        - Increased risk of coronary heart disease, stroke, and peripheral vascular disease.
      - Long-term complications may include infections and delayed healing.

Acute Complications

  • Diabetic Ketoacidosis (DKA):
      - Characterized by: hyperglycemia, ketosis, metabolic acidosis.
      - Common in T1DM but can occur in T2DM under extreme stress.
      - Clinical Manifestations:
        - Dehydration, dry mucous membranes, tachycardia, abdominal pain, Kussmaul respirations, sweet fruit breath odor, blood glucose levels ≥ 250 mg/dL.

  • Hyperosmolar Hyperglycemia Syndrome (HHS):
      - Life-threatening condition more common in elderly T2DM patients.
      - Characterized by severe hyperglycemia (usually >600 mg/dL) without ketoacidosis.
      - Clinical Manifestations: Neurologic symptoms such as somnolence and coma due to increased serum osmolality.

Treatment of Diabetes

  • Management Options:
      - Insulin: Exogenous insulin is essential for T1DM management; also prescribed for T2DM as necessary.
      - Oral Antidiabetic Medications:
        - Metformin (first-line therapy for T2DM).
        - Sulfonylureas, thiazolidinediones, DPP-4 inhibitors, SGLT2 inhibitors, etc.
      - Lifestyle Modifications: Diet, exercise, and weight management are crucial for T2DM management.

  • Insulin Regimens:
      - Basal-bolus therapy: Multiple daily injections or insulin pump use tailored to mimic normal insulin production (long-acting basal insulin combined with rapid-acting bolus insulin before meals).

Gestational Diabetes

  • Definition: Develops during pregnancy; glucose levels 10%-20% lower than pre-pregnancy levels; can be diet-controlled or require insulin.

  • Prevalence: Affects approximately 2% to 10% of pregnancies; increases risks of complications for mothers and infants.

  • Screening Guidelines: Recommended for all women at first prenatal visit, followed by glucose screening between 24-28 weeks.

Diabetes Medications

Insulin Preparations

  • Types of Insulin:
      - Rapid-acting: e.g., Lispro, Aspart.
      - Short-acting: e.g., Regular.
      - Intermediate-acting: e.g., NPH.
      - Long-acting: e.g., Glargine.

  • Insulin Characteristics: Vary by onset, peak, and duration. Ex: Rapid-acting insulins have onset within 10-30 min, peak at 30 min-3 hrs, and duration of 3-5 hrs.

Oral Agents

  • Biguanides: Metformin, reduces hepatic glucose production and improves insulin sensitivity.

  • Sulfonylureas: Increase insulin release from the pancreas.

  • Thiazolidinediones: Increase insulin sensitivity at target tissues.

  • A-Glucosidase Inhibitors: Slow carbohydrate absorption in the intestine.

  • DPP-4 Inhibitors: Increase incretin levels to enhance glucose control.

  • SGLT2 Inhibitors: Increase urinary glucose excretion.

Patient Education

  • Patients should be educated on the importance of monitoring blood glucose levels, recognizing symptoms of hypo/hyperglycemia, and adhering to prescribed regimens. Awareness of complications and the importance of lifestyle changes is crucial in diabetes management.