hyper and hypoglycemia dr alaa 1446

2. Hyperglycemia

2.1. Causes of Hyperglycemia

  • Diabetes Mellitus: Chronic condition affecting glucose metabolism.

  • Endocrine Disorders: Such as hyperthyroidism, hyperpituitarism, and hyperadrenalism.

  • Organ Disorders: Involving the liver and pancreas.

  • Emotional Factors: Stress from anger, fear, or excitement.

2.2. Types of Hyperglycemia

  • Impaired Glucose Tolerance: An early sign of diabetes.

  • Impaired Fasting Glycemia: Elevated fasting glucose levels.

  • Gestational Diabetes Mellitus: Diabetes occurring during pregnancy.

  • Alimentary Hyperglycemia: Following specific surgical procedures like subtotal gastrectomy.

3. Diabetes Mellitus (DM)

3.1. Definition

  • A metabolic disease marked by:

    • Increased blood glucose (hyperglycemia)

    • Decreased glucose tolerance

  • Results from:

    • Insufficient insulin production

    • Insufficient cellular response to insulin

3.2. Classification of Diabetes Mellitus

  1. Type 1 Diabetes: Autoimmune destruction of insulin-producing beta cells, leading to insulin deficiency.

  2. Type 2 Diabetes: Progressive beta cell dysfunction against a backdrop of insulin resistance.

  3. Gestational Diabetes Mellitus (GDM): Diabetes diagnosed in pregnancy, usually resolving postpartum.

  4. Other Specific Types: Including monogenic syndromes, pancreatic disorders, and drug-induced diabetes.

4. Comparison of Diabetes Types

4.1. Type I vs Type II DM

Type I DM (Insulin-Dependent Diabetes Mellitus)

  • Incidence: 10%

  • Age: Usually diagnosed in childhood/adolescence.

  • Onset: Rapid, often presenting with diabetic coma.

  • Cause: Autoimmune destruction of beta cells.

  • Blood Insulin Level: Low or absent.

  • Treatment: Insulin injections.

Type II DM (Non-Insulin Dependent Diabetes Mellitus)

  • Incidence: 90%

  • Age: Typically diagnosed later in life.

  • Onset: Slow onset.

  • Cause: Insulin resistance.

  • Blood Insulin Level: Initially normal or high but may decrease over time.

  • Treatment: Oral hypoglycemic drugs.

5. Laboratory Investigations

5.1. Key Investigations for Diabetes Management

  1. Assessment of Plasma Glucose (PG) Levels.

  2. Oral Glucose Tolerance Test (OGTT).

  3. Glycated Hemoglobin (HbA1c) Determination.

  4. Ketone Measurement (urine & blood).

  5. Plasma Insulin Level Determination.

  6. HOMA-IR Calculation.

  7. C-peptide Measurement.

  8. Microalbuminuria Detection.

5.2. Plasma Glucose Measurement Techniques

  • Fasting Specimen: Blood collected after 8-10 hours of fasting.

  • Post-Prandial Specimen: Blood collection 2 hours after a meal.

  • Random Specimen: Blood collected anytime, regardless of meals.

6. OGTT Methodology

6.1. Principles of OGTT

  • Measures how effectively the body manages glucose.

  • Used for diagnosing:

    • Gestational Diabetes

    • Impaired Glucose Tolerance

    • Diabetes Mellitus

6.2. OGTT Procedure

  1. Collect fasting venous blood and urine.

  2. Administer glucose load (0.75 g/kg body weight).

  3. Collect blood and urine at 30-minute intervals for 2 hours, especially for gestational diabetes.

  4. Graph results over time, noting critical glucose levels.

6.3. Results Interpretation

  • Normal Subjects: PG rises then falls back within normal range post-glucose load.

  • Diabetic Patients: Elevated fasting PG and excessive rise post-glucose load may lead to glucosuria.

7. Impaired Glucose Tolerance (IGT)

  • Considered a precursor to diabetes.

  • Defined by fasting glucose 100-125 mg/dL or 2-hour post-prandial between 140-199 mg/dL.

  • Management includes weight loss and increased physical activity.

8. Diagnostic Criteria for Diabetes Mellitus

  • FPG ≥ 126 mg/dL (no caloric intake for 8 hours).

  • 2-hour PG ≥ 200 mg/dL post 75g glucose load.

  • HbA1c ≥ 6.5%.

  • Random PG ≥ 200 mg/dL with classic symptoms.

9. Urine Glucose Testing (Glucosuria)

  • Dipstick Testing: Useful for screening but not sensitive enough for definitive diagnosis.

  • Glucosuria Causes: Include diabetes mellitus, alimentary hyperglycemia, gestational diabetes, and renal glycosuria.

10. Ketone Bodies in Urine

  • Indicators of acute insulin deficiency leading to ketoacidosis.

  • Detected using testing strips, with results indicating severity from negative to positive results.

  • Important in Type 1 DM under certain conditions (e.g., high blood glucose).

11. Glycated Hemoglobin (HbA1c)

  • Reflects average blood glucose levels over 2-3 months.

  • Reference range: < 5.7%.

  • A 1% change in HbA1c correlates with ~30-35 mg/dL blood glucose change.

12. Monitoring Factors Influencing Glycation

  • Age, race/ethnicity, anemia disorders, and RBC turnover rates may affect HbA1c levels independently of glucose levels.

13. Microalbuminuria

  • Indicates early diabetic nephropathy.

  • Defined as small amounts of albumin (30-300 mg/day) detectable in the urine.

14. Diabetic Ketoacidosis (DKA)

  • Characterized by insulin deficiency leading to metabolic derangements (e.g., hyperkalemia, acidosis).

  • Associated lab findings:

    • High potassium levels

    • Low pH and bicarbonate levels

    • Elevated osmolarity and renal impairment indicators (urea and creatinine).