Type 1 Diabetes Mellitus
An autoimmune disease that destroys pancreatic beta cells until insulin secretion fails almost completely, so glucose rises unchecked and unopposed lipolysis drives ketone production: the mechanism behind both the presentation and the risk of diabetic ketoacidosis.
Definition
Type 1 diabetes is autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency and lifelong dependence on exogenous insulin, typically presenting in childhood or young adulthood with hyperglycaemia and a tendency to ketoacidosis.
First principles
Type 1 diabetes is autoimmune beta-cell destruction, not resistance
T-cell mediated autoimmune attack, often marked by islet autoantibodies (anti-GAD, anti-IA2, anti-insulin) and HLA-DR3/DR4 associations, progressively destroys the insulin-secreting beta cells of the pancreas. Unlike type 2 diabetes, where insulin is present but ineffective, type 1 diabetes leaves the body with too little insulin, full stop. Because destruction can proceed quickly, especially in children and young adults, the disease often presents abruptly over days to weeks rather than evolving silently over years.
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