What is the key pathophysiology of type 2 diabetes mellitus?

• A. Autoimmune destruction of beta cells
• B. Insulin resistance with progressive beta-cell dysfunction
• C. Insulin deficiency only
• D. Excess hepatic glucose production

Answer: (B)

Type 2 diabetes mainly arises from insulin resistance in peripheral tissues combined with a progressive decline in pancreatic beta-cell insulin secretion. In the early stages, tissues don’t respond well to insulin, so the pancreas compensates by producing more insulin to keep blood glucose in check. Over time, the beta cells can’t sustain that workload and insulin secretion falls, leading to rising glucose levels. The liver also contributes by not suppressing glucose production properly because of insulin resistance, which worsens hyperglycemia. This combination—insulin resistance with expanding beta-cell dysfunction—best explains the pathophysiology of type 2 diabetes.