What are the different types of diabetes and their management plans?

Types of Diabetes and Their Management Plans

Diabetes mellitus is classified into four main categories: Type 1 diabetes, Type 2 diabetes, Gestational diabetes mellitus (GDM), and Specific types of diabetes due to other causes, each requiring distinct management approaches. 1

Type 1 Diabetes

Characteristics

• Caused by autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency 2
• Accounts for only 5-10% of all diabetes cases 1
• Often presents with:
  • Younger age at diagnosis
  • Lower BMI
  • Unintentional weight loss
  • Ketoacidosis (40-50% of children present with DKA) 1
  • High glucose levels at presentation
  • Presence of autoimmune markers (islet cell autoantibodies, GAD antibodies, insulin autoantibodies) 1
  • Strong genetic associations, particularly with HLA genes 1

Management Plan

• Insulin therapy is essential and lifelong
• Multiple daily injections or continuous subcutaneous insulin infusion (insulin pump)
• Basal-bolus approach using human insulin analogs for more physiological insulin replacement 3
• Regular blood glucose monitoring or continuous glucose monitoring
• Carbohydrate counting and matching insulin doses to food intake
• Regular physical activity with appropriate insulin adjustments
• Education on hypoglycemia recognition and management
• Regular screening for complications (retinopathy, nephropathy, neuropathy)

Type 2 Diabetes

Characteristics

• Progressive loss of adequate β-cell insulin secretion frequently on the background of insulin resistance 2, 1
• Typically associated with:
  • Older age at onset
  • Higher BMI or obesity
  • Sedentary lifestyle
  • Negative autoantibody tests
  • Normal or elevated C-peptide levels 1
  • Often asymptomatic for years 4

Management Plan

• Lifestyle modifications (cornerstone of treatment):
  • Weight loss (5-10% of body weight)
  • Regular physical activity (150 minutes/week)
  • Dietary modifications (reduced calorie, carbohydrate control)
• Pharmacological therapy (stepwise approach):
  1. Metformin as first-line therapy
  2. Add second agent based on patient factors and comorbidities:
     • GLP-1 receptor agonists
     • SGLT-2 inhibitors
     • DPP-4 inhibitors
     • Sulfonylureas
     • Thiazolidinediones
  3. Insulin therapy when oral agents fail to achieve glycemic targets
• Regular monitoring of glycemic control (HbA1c every 3-6 months)
• Aggressive management of cardiovascular risk factors
• Regular screening for complications

Gestational Diabetes Mellitus (GDM)

Characteristics

• Diabetes diagnosed in the second or third trimester of pregnancy that was not clearly overt diabetes prior to gestation 2, 1
• Affects approximately 8.3% of pregnancies 1
• Approximately 70% of females with GDM will develop diabetes over time 1

Management Plan

• Screening typically at 24-28 weeks of gestation 1
• Glycemic targets:
  • Fasting blood glucose <5.2 mmol/L
  • 2-hour postprandial <6.6 mmol/L 1
• Management includes:
  • Dietary measures
  • Regular blood glucose monitoring
  • Insulin therapy in 20-30% of cases 1
  • Oral agents generally not recommended during pregnancy
• Postpartum follow-up for reclassification of glycemic status
• Long-term follow-up due to increased risk of developing type 2 diabetes

Specific Types of Diabetes Due to Other Causes

Subtypes

1. Monogenic diabetes syndromes:

   • Neonatal diabetes
   • Maturity-onset diabetes of the young (MODY) 2, 1

2. Diseases of the exocrine pancreas:

   • Cystic fibrosis
   • Pancreatitis
   • Pancreatic cancer 2, 1

3. Drug or chemical-induced diabetes:

   • Glucocorticoid use
   • Treatment of HIV/AIDS
   • Post-organ transplantation
   • Medications like thiazides and beta-blockers 1

4. Genetic defects in insulin action and endocrinopathies 1

Management Plan

• Treatment directed at underlying cause when possible
• Management tailored to specific etiology
• For MODY subtypes, specific treatments based on genetic diagnosis:
  • Sulfonylureas for HNF1A and HNF4A MODY
  • Low-dose sulfonylureas for KCNJ11 and ABCC8 mutations
• For pancreatic disease, insulin often required due to absolute insulin deficiency
• For drug-induced diabetes, consider medication alternatives when possible

Important Clinical Considerations

• Classification is not always straightforward at diagnosis, and misdiagnosis is common (up to 40% of adults with new-onset type 1 diabetes) 1

• Regular reassessment of diabetes classification is important, especially when treatment response is suboptimal 1

• Testing for islet autoantibodies and C-peptide can help distinguish between type 1 and type 2 diabetes when diagnosis is unclear 1

• Diagnostic criteria for diabetes include:

  • A1C ≥6.5% (48 mmol/mol)
  • Fasting plasma glucose ≥126 mg/dL (7.0 mmol/L)
  • 2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during OGTT
  • Random plasma glucose ≥200 mg/dL (11.1 mmol/L) with classic symptoms 1

• All forms of diabetes require monitoring for and prevention of long-term complications, including microvascular (retinopathy, nephropathy, neuropathy) and macrovascular (cardiovascular disease) complications