Diabetes Mellitus Overview

Diabetes Mellitus Definition

• Diabetes mellitus is a metabolic disorder characterized by high blood glucose levels due to either insufficient insulin production or the body's inability to effectively use insulin.

Global and Local Prevalence

• Diabetes is a major health concern globally, contributing significantly to morbidity and healthcare costs.
• Egypt is among the top 10 countries with the highest number of diabetes patients.
• The Middle East and North Africa (MENA) region is expected to see an 86% increase in diabetes cases from 2019 to 2045.
• The prevalence of diabetes in Egypt is around 20.9% among adults aged 20 to 79 years.

Diabetes Classifications

• Type 1 Diabetes: Characterized by the body's immune system attacking and destroying insulin-producing beta cells in the pancreas, leading to absolute insulin deficiency.
  • Immune-mediated: Caused by an autoimmune response.
  • Idiopathic: Cause unknown.
• Type 2 Diabetes: Occurs when the body either doesn't produce enough insulin or can't use insulin effectively, resulting in hyperglycemia.
• Predominantly insulin resistance: The body struggles to use insulin effectively.
• Predominantly insulin secretory defect: The pancreas doesn't produce enough insulin.
• Other Specific Types of Diabetes:
  • Genetic defects: Involving beta cell function (MODY 1-6) or insulin action.
  • Diseases of the exocrine pancreas: Including pancreatitis, pancreatectomy, cystic fibrosis, and hemochromatosis.
  • Endocrinopathies: Hormonal disorders like acromegaly, Cushing's syndrome, and hyperthyroidism.
  • Drug or chemical induced: Often caused by use of glucocorticoids.
  • Genetic syndromes associated with diabetes: Such as Down syndrome, Klinefelter syndrome, and Turner syndrome.
• Gestational Diabetes Mellitus (GDM): Occurs during pregnancy, often resolving after childbirth.

Insulin Resistance Syndrome (Metabolic Syndrome)

• A cluster of metabolic conditions that increase the risk of cardiovascular disease and diabetes.
• Key features include:
  • Central obesity (excess fat around the abdomen)
  • Hypertriglyceridemia (high levels of triglycerides)
  • Low high-density lipoprotein (HDL) cholesterol
  • Hyperglycemia (high blood sugar)
  • Hypertension (high blood pressure)

Prediabetes

• A condition where blood glucose levels are higher than normal but not yet meeting the criteria for diabetes.

Clinical Features

• Type 1 Diabetes:
  • Symptoms: Polydipsia (increased thirst), polyuria (frequent urination), enuresis (bedwetting), chronic weight loss, and failure to thrive in children.
  • Severe presentations: Dehydration, frequent vomiting, diabetic ketoacidosis (DKA), and shock.
• Type 2 Diabetes:
  • Symptoms: Often asymptomatic initially; polydipsia, polyuria, chronic skin infections, vaginitis, overweight or obesity, and Acanthosis nigricans (darkening of the skin).
  • Complications: Neuropathic or cardiovascular complications can sometimes be present at diagnosis.

Laboratory Findings for Diagnosis

• Plasma glucose: Fasting blood glucose, random blood glucose, and postprandial glucose.
• Oral glucose tolerance test (OGTT): Measures blood glucose levels after drinking a sugary drink.
• Glycated hemoglobin (HbA1c): Reflects average blood glucose levels over the past 2-3 months.
• Urine glucose: Detects excess glucose in the urine.
• Urine and blood ketones: Indicates breakdown of fat for energy, occurring in DKA.

Treatment Regimens

• Lifestyle Modifications:
  • Medical Nutrition Therapy (MNT): Dietary changes to control calorie intake and manage blood sugar levels.
  • Physical Activity: Regular exercise helps improve insulin sensitivity and lowers blood sugar.
• Medications for Treating Hyperglycemia:
  • Insulin Secretagogues:
    • Sulfonylureas: Stimulate insulin release from the pancreas.
    • Meglitinide Analogs: Similar to sulfonylureas, but have a shorter duration of action.
  • Insulin Sensitizers:
    • Metformin: Improves insulin sensitivity in the liver, muscles, and adipose tissue.
    • Thiazolidinediones: Enhance insulin sensitivity by increasing glucose uptake and utilization.
  • α-Glucosidase Inhibitors:
    • Acarbose: Slows down the breakdown of complex carbohydrates in the digestive system, reducing glucose absorption.
  • Incretins:
    • GLP-1 Receptor Agonists: Mimic the actions of GLP-1, a hormone that stimulates insulin release and reduces glucagon secretion.
    • DPP-4 Inhibitors: Prevent the breakdown of GLP-1 and GIP, enhancing their effects.
  • Sodium-Glucose Co-Transporter 2 (SGLT2) Inhibitors: Block the reabsorption of glucose in the kidneys, increasing its excretion in urine.
• Insulin Therapy:
  • Insulin Preparations: Various types of insulin available, differing in onset, peak, and duration of action.
  • Bioavailability Characteristics: Factors influencing how quickly and effectively insulin enters the bloodstream.

Transplantation

• Pancreas Transplantation: Replacement of the pancreas with a donor one.
• Islet Transplantation: Transplantation of insulin-producing cells from a donor's pancreas.