Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both.
It can occur at any age and the earlier the onset, the more serious is the long-term damage, dysfunction and failure of various organs due to the chronic hyperglycemia with DM patients having <10 years in life span compared to non-DM patients.
Type 1 DM patients have complete insulin deficiency due to beta-cell destruction. It may be immune-mediated or idiopathic. It more commonly occurs in children 7-15 years of age but may occur at any age.
Type 2 DM patients have insulin resistance and relative insulin deficiency.
Neonatal DM is hyperglycemia that occurs in the first 6 months of life.