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

Different Types of Diabetes and Their Management Approaches

Diabetes is classified into four main categories: Type 1, Type 2, Gestational Diabetes Mellitus (GDM), and specific types due to other causes, each requiring distinct management approaches based on their underlying pathophysiology. 1

Main Types of Diabetes

1. Type 1 Diabetes

• Pathophysiology: Due to autoimmune β-cell destruction, leading to absolute insulin deficiency 1
• Clinical Presentation:
  • Often presents with classic symptoms of polyuria/polydipsia
  • Approximately one-third of children present with diabetic ketoacidosis (DKA) 1
  • Adult onset may be more variable and may not present with classic symptoms 1
• Management:
  • Insulin therapy is essential for survival
  • Multiple daily injections or continuous subcutaneous insulin infusion (insulin pump) 2
  • Carbohydrate counting and meal planning
  • Regular blood glucose monitoring or continuous glucose monitoring
  • Education on hypoglycemia recognition and management

2. Type 2 Diabetes

• Pathophysiology: Progressive loss of β-cell insulin secretion frequently on the background of insulin resistance 1
• Clinical Presentation:
  • Often insidious onset
  • May be asymptomatic and discovered during routine screening
  • Occasionally presents with DKA, particularly in ethnic minorities 1
• Management:
  • Lifestyle modifications (diet, exercise, weight management)
  • Oral antidiabetic medications (metformin typically first-line)
  • Injectable GLP-1 receptor agonists
  • Insulin therapy when oral agents fail to achieve glycemic targets
  • Cardiovascular risk reduction strategies

3. Gestational Diabetes Mellitus (GDM)

• Definition: Diabetes diagnosed in the second or third trimester of pregnancy that was not clearly overt diabetes prior to gestation 1
• Clinical Considerations:
  • Affects approximately 8.3% of pregnancies 1
  • Screening typically occurs at 24-28 weeks of gestation
  • Increased risk of maternal and fetal complications
• Management:
  • Dietary measures with blood glucose monitoring 4-6 times daily
  • Insulin therapy in 20-30% of cases 1
  • Glycemic targets: fasting blood glucose <5.2 mmol/L and 2-hour postprandial <6.6 mmol/L 1
  • Postpartum follow-up to identify persistent diabetes

4. Specific Types Due to Other Causes

• Monogenic Diabetes Syndromes:

  • Maturity-onset diabetes of the young (MODY)
  • Neonatal diabetes
  • Characterized by specific genetic mutations 3
  • Management varies by subtype (e.g., MODY2 often requires only diet, MODY3 may respond to sulfonylureas) 4

• Diseases of the Exocrine Pancreas:

  • Cystic fibrosis-related diabetes
  • Pancreatitis
  • Pancreatic cancer 5
  • Management focuses on treating underlying condition and providing insulin as needed

• Drug or Chemical-Induced Diabetes:

  • Glucocorticoid use
  • HIV/AIDS treatment
  • Post-organ transplantation 1
  • Management includes addressing the causative agent when possible and treating hyperglycemia

Diagnostic Considerations

Diagnostic Criteria

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

Diagnostic Challenges

• Classification is not always straightforward at diagnosis 1
• Misdiagnosis is common and can occur in up to 40% of adults with new-onset type 1 diabetes 1
• Consider testing for islet autoantibodies (GAD, IA-2, ZnT8) when the diabetes type is unclear 1
• C-peptide testing can help distinguish between type 1 and type 2 diabetes after disease duration of >3 years 1

Special Considerations

Latent Autoimmune Diabetes in Adults (LADA)

• Shares features with both type 1 and type 2 diabetes
• Characterized by adult-onset, presence of islet autoantibodies, and initial non-insulin dependence 6
• Management typically progresses from oral agents to insulin as β-cell function declines

Ketosis-Prone Diabetes (KPD)

• Presents with ketoacidosis but may not require long-term insulin therapy
• More common in ethnic minorities 6
• Management requires initial insulin therapy with possible transition to oral agents

Clinical Pearls

• The traditional paradigm that type 1 diabetes occurs only in children and type 2 only in adults is no longer accurate 1
• Both diseases occur across all age groups
• Diabetes classification is important for determining appropriate therapy but may evolve over time as the clinical picture becomes clearer 1
• Regular reassessment of diabetes classification is important, especially when treatment response is suboptimal

Remember that early and accurate diagnosis of diabetes type is crucial for appropriate management and prevention of complications affecting morbidity, mortality, and quality of life.