Diabetes is a clinically heterogeneous disorder. Hitherto, predominantly classified into:
- Type 1 Diabetes Mellitus (T1 DM)
- Type 2 Diabetes Mellitus (T2 DM)
- Other diverse types like MODY (maturity onset diabetes in young), Drug related DM, LADA (latent autoimmune diabetes of adults), Pancreatogenic diabetes mellitus, GDM (Gestational Diabetes Mellitus) and infections related.
It has been a common manifestation of other endocrine disorders like Cushing’s disease, Acromegaly and Hyperthyroidism.
Type 1 Diabetes Mellitus
Type 1 Diabetes Mellitus is caused by autoimmune destruction of insulin secreting pancreatic beta cells leading to complete dissipation of insulin secretory capacity. It is distinguished by early onset, Insulin dependence, highly fluctuating blood glucose levels and association with other autoimmune diseases.
Type 2 Diabetes Mellitus
Type 2 Diabetes Mellitus is by far the most common cause of diabetes seen in 90% of cases. It is characterised by late onset (age ≥ 40 yrs), associated with overweight, sedentary life style, strong family history and noninsulin dependence atleast in early stages.
MODY is a distinct disorder caused by genetic defects in beta cell function (insulin secreting cells) which occurs in familial generations, is non-insulin dependent and typically affects younger individuals (age ≤25 yrs)
LADA is associated with other autoimmune diseases (i.e. our own immunity working against our own organs) and is akin to T1DM in this regard. They tend to be lean and might require insulin therapy much earlier than T2DM subjects.
Pancreatic damage due to alcohol, cancer or drugs can lead to diabetes which may be persistent depending on the etiology.
Drugs like phenytoin, steroids and thiazides (used to treat hypertension) and syndromes like Downs and Turners can lead to diabetes.