Armando Hasudungan

Biology and Medicine Tutorials

Diabetes Mellitus type I


Overview Type 1 diabetes is B-cell destruction leading to absolute insulin deficiency. It accounts for 5-10% of all diabetes. Type I diabetes is divided into two types: Immune mediated and idiopathic. The traditional paradigm is of childhood onset with acute symptoms of DKA.


Diabetes: A group of metabolic diseases in which there are high blood sugar levels over a prolonged period.
Diabetes Mellitus Type I: Autoimmune destruction of beta cells in the pancreas
Diabetes Mellitus Type II: Insulin resistance followed by beta cell atrophy
Gestational Diabetes: diabetes diagnosed during the second half of pregnancy with no prior existing diabetes.


The age of onset and rate of B-cell destruction is quite variable:

  • Rapid in infants and children
  • Slow in others (mainly adults) such as occurs in Latent Autoimmune Diabetes of Adulthood (LADA).

This influences clinical presentation and may confuse diagnosis.


Acute onset of hyperglycaemic symptoms with ketoacidosis:

  • Random plasma glucose > 11.1 mmol/L consistent with diagnosis
  • HbA1c is not used in diagnosis

Autoimmune markers are not routinely used but can include:

  • Glutamic acid decarboxylase (GAD65)
  • Insulin (IAA)
  • Tyrosine phosphatases (IA-2 & IA-2B)
  • ZnT8

Low or undetectable plasma C-peptide level supports the diagnosis.

Latent autoimmune diabetes of adulthood

  • A subtype of autoimmune Type 1 diabetes sometimes misdiagnosed as T2D.
  • Slowly progressive destruction of Beta cells.
  • May appear to respond to oral agents initially.
  • Less likely to have other features of metabolic syndrome (central obesity, HT, dyslipidaemia).
  • More likely to have history of other autoimmune diseases.
  • Starting insulin early may help to preserve beta cell insulin production

Criteria to standardize the definition:

  1. Age of onset usually > 30y
  2. Positive titre for at least one T1D autoantibody
  3. Not treated with insulin within the first 6 months after diagnosis


General target

  • HbA1c target <7
  • BSL 4-6 pre meal and 4-8 post meal

Non-pharmacological methods

  • Patient education and pscyhosocial support
    • Hypoglcyaemic symptoms and management
    • Driving
  • Glucose monitoring
    • Self glucose monitoring
    • Continous glucose monitoring (which measure inersitial glucose)
  • Multidisplnary team
    • Opthalmologist
    • Nephrologist
    • Podiatrist

Pharmacological treatment

  • Insulin (causes weight gain)
    • Continous subcutaenous insulin pump therapy
  • Non-insulin treatment (all cause weight loss)
  • Pramlintide
  • Metformin
  • GLP-1 receptor agonist
  • SGLT2 inhibitors

Surgical treatment

  • Pancreas transplantation (curative)
  • Islet transplantation

Complications and Prognosis


  • Increased risk of other autoimmune disease
    • Autoimmune thyroid disease
    • Addison's disease
    • Coeliac disease
    • Vitiligo
  • Diabetic ketoacidosis