Diabetes Mellitus: Type 1 vs Type 2

Diabetes Mellitus

• Type 1 Diabetes Mellitus:
  • Lack of insulin production or production of defective insulin
  • Affected patients need exogenous insulin
  • Complications include diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic syndrome (HHS)
• Type 2 Diabetes Mellitus:
  • Most common type (90% of all cases)
  • Caused by insulin deficiency and insulin resistance
  • Many tissues are resistant to insulin, including reduced number of insulin receptors and less responsive insulin receptors

Signs and Symptoms of Diabetes

• Elevated fasting blood glucose (higher than 126 mg/dL) or a hemoglobin A1C (HbA1C) level greater than or equal to 6.5%
• Polyuria
• Polydipsia
• Polyphagia
• Glycosuria
• Unexplained weight loss
• Fatigue
• Blurred vision

Type 2 Diabetes Mellitus Comorbid Conditions

• Obesity
• Coronary heart disease
• Dyslipidemia
• Hypertension
• Microalbuminemia (protein in the urine)
• Increased risk for thrombotic (blood clotting) events
• These comorbidities are collectively referred to as metabolic syndrome, insulin-resistance syndrome, or syndrome X

Major Long-Term Complications of Both Types of Diabetes

• Macrovascular (atherosclerotic plaque):
  • Coronary arteries
  • Cerebral arteries
  • Peripheral vessels
• Microvascular (capillary damage):
  • Retinopathy
  • Neuropathy
  • Nephropathy

Gestational Diabetes

• Hyperglycemia that develops during pregnancy
• Insulin must be given to prevent birth defects
• Usually subsides after delivery
• 30% of patients may develop type 2 DM within 10 to 15 years

Nonpharmacologic Treatment Interventions

• Type 1: Always requires insulin therapy
• Type 2:
  • Weight loss
  • Improved dietary habits
  • Smoking cessation
  • Reduced alcohol consumption
  • Regular physical exercise

Glycemic Goal of Treatment

• HbA1C of less than 7%
• Fasting blood glucose goal for diabetic patients: 80 to 130 mg/dL

Treatment Options for Diabetes

• Type 1: Insulin therapy
• Type 2:
  • Lifestyle changes
  • Oral drug therapy
  • Insulin when the above no longer provide glycemic control

Insulin

• Function as a substitute for the endogenous hormone
• Effects are the same as normal endogenous insulin
• Restores the diabetic patient's ability to:
  • Metabolize carbohydrates, fats, and proteins
  • Store glucose in the liver
  • Convert glycogen to fat stores

Types of Insulin

• Rapid-acting:
  • Onset of action: 5 to 15 minutes
  • Peak: 1 to 2 hours
  • Duration: 3 to 5 hours
  • Examples: insulin lispro (Humalog), insulin aspart (NovoLog), insulin glulisine (Apidra)
• Short-acting:
  • Onset: 30 to 60 minutes
  • Peak: 2.5 hours
  • Duration: 6 to 10 hours
  • Examples: regular insulin (Humulin R)
• Intermediate-acting:
  • Onset: 1 to 2 hours
  • Peak: 4 to 8 hours
  • Duration: 10 to 18 hours
  • Examples: insulin isophane suspension (NPH)
• Long-acting:
  • Onset: 1 to 2 hours
  • Peak: none
  • Duration: 24 hours
  • Examples: insulin glargine (Lantus), insulin detemir (Levemir)

Sliding Scale vs Bolus Insulin Dosing

• Sliding-scale insulin dosing:
  • SUBQ rapid-acting or short-acting insulins are adjusted according to blood glucose test results
  • Typically used in hospitalized diabetic patients or those on total parenteral nutrition or enteral tube feedings
• Basal-bolus insulin dosing:
  • Preferred method of treatment for hospitalized patients with DM
  • Mimics a healthy pancreas by delivering basal insulin constantly as a basal and then as needed as a bolus
  • Basal insulin is a long-acting insulin (insulin glargine), and bolus insulin is a rapid-acting insulin (insulin lispro or insulin aspart)

Non-Insulin Antidiabetic Drugs

• Biguanides:
  • Mechanism of action: decrease production of glucose by the liver, decrease intestinal absorption of glucose, and increase uptake of glucose by tissues
  • Adverse effects: primarily affects gastrointestinal (GI) tract, may also cause metallic taste, reduced vitamin B12 levels
  • Contraindications: renal or hepatic disease
  • Example: metformin (Glucophage)
• Sulfonylureas:
  • Mechanism of action: stimulate insulin secretion from the beta cells of the pancreas, thus increasing insulin levels
  • Adverse effects: hypoglycemia, hematologic effects, nausea, epigastric fullness, heartburn
  • Contraindications: hypersensitivity to Sulphur, pregnancy
  • Examples: glimepiride (Amaryl), glipizide (Glucotrol), glyburide (DiaBeta)
• Glinides:
  • Mechanism of action: similar to sulfonylureas, increase insulin secretion from the pancreas
  • Adverse effects: hypoglycemia, weight gain
  • Examples: repaglinide (Prandin), nateglinide (Starlix)
• Thiazolidinediones (glitazones):
  • Mechanism of action: decrease insulin resistance, increase glucose uptake and use in skeletal muscle
  • Adverse effects: can cause or exacerbate heart failure, peripheral edema, weight gain, decreased bone marrow density
  • Contraindications: heart failure
  • Example: pioglitazone (Actos)
• Alpha-glucosidase inhibitors:
  • Mechanism of action: decrease intestinal absorption of glucose
  • Adverse effects: flatulence, diarrhea, abdominal pain
  • Contraindications: certain bowel disorders
  • Examples: acarbose (Precose), miglitol (Glyset)
• Incretin mimetics:
  • Mechanism of action: mimic naturally secreted incretin hormones, increase insulin synthesis and lower glucagon secretion
  • Adverse effects: upper respiratory tract infection, headache, diarrhea
  • Contraindications: pancreatitis
  • Examples: sitagliptin (Januvia), saxagliptin (Onglyza), linagliptin (Tradjenta), alogliptin (Nesina)
• SGLT2 inhibitors:
  • Mechanism of action: inhibit SGLT2, leading to a decrease in blood glucose caused by an increase in renal glucose excretion
  • Adverse effects: genital yeast infections, urinary tract infections, increased urination
  • Contraindications: diabetic ketoacidosis, moderate to severe kidney impairment
  • Examples: canagliflozin (Invokana), dapagliflozin (Farxiga), empagliflozin (Jardiance), ertugliflozin (Steglatro)

This quiz covers the differences between Type 1 and Type 2 Diabetes Mellitus, including symptoms and complications such as diabetic ketoacidosis and hyperosmolar hyperglycemic syndrome.