Type I Diabetes

“Complex metabolic disorder characterised by persistent hyperglycaemia (insulin deficiency)”

Risk Factors

• Family history of type 1 diabetes (strong genetic component)

Aetiology

• Absolute deficiency of insulin

Pathophysiology

• Autoimmune destruction of beta cells → absolute deficiency of insulin
  • Increased hepatic glucose output
  • Decreased glucose uptake into adipocytes
  • Decreased glucose uptake in skeletal muscle
  • Decreased glycogenesis in liver and skeletal muscle

Clinical Presentation

• Onset is usually adolescent but can occur at any age
• Presentation includes:
  • Polyuria
  • Polydipsia
  • Age of onset younger than 50 years
  • Rapid weight loss
  • BMI below 25 kg/m²

Investigations

• Bloods:
  • Main test – HbA1c > 48 mmol/mol
  • Others:
    • Random plasma glucose > 11 mmol/L
    • Fasting plasma glucose > 7 mmol/L
    • Oral glucose tolerance test 2h > 11 mmol/L
    • Only measure diabetes-specific autoantibodies if patient had atypical features that don’t fit the usual presentation (e.g. >50 years old, BMI 25 kg/m² or above)
• Imaging: n/a
• Special: n/a

Management

• Insulin therapy

Complications

• Diabetic ketoacidosis
• Diabetic foot
• Macrovascular complications:
  • Increased risk of stroke
  • Myocardial Infarction
  • Peripheral vascular disease
• Microvascular complications:
  • Diabetic retinopathy
  • Diabetic nephropathy
  • Diabetic neuropathy
  • Erectile dysfunction