All Sample Questions

Diabetes Mellitus 1

Question

Vignette: A 45-year-old woman presents to her primary care physician with complaints of fatigue, weight loss, and frequent urination. She also reports that she has been drinking more water than usual. She has a family history of diabetes mellitus. On physical examination, her blood pressure is found to be 130/85 mmHg, and her BMI is 29 kg/m2. Her fasting blood glucose level is 126 mg/dL. A repeat fasting blood glucose test after two days confirms the same blood glucose level.

Question: What is the most likely pathophysiology underlying this patient's condition?

Choices

A. Defective insulin receptors

B. Autoimmune destruction of pancreatic beta cells

C. Insulin resistance and relative insulin deficiency

D. Inappropriate glucagon secretion

E. Deficiency of the GLUT-2 transporter

Answer

C. Insulin resistance and relative insulin deficiency

Explanation

The patient's symptoms and family history, along with the elevated fasting blood glucose levels, suggest the diagnosis of type 2 diabetes mellitus. The primary pathophysiology of type 2 diabetes is insulin resistance and relative insulin deficiency. Initially, insulin resistance occurs, where the body's tissues are less responsive to insulin. To compensate, the pancreas produces more insulin. Over time, however, the pancreas is unable to keep up with the increased demand for insulin, leading to relative insulin deficiency. This differs from type 1 diabetes, where there is an autoimmune destruction of the pancreatic beta cells (Choice B), leading to absolute insulin deficiency. Defective insulin receptors (Choice A) are seen in conditions like Leprechaunism, a rare autosomal recessive disorder. Inappropriate glucagon secretion (Choice D) and deficiency of the GLUT-2 transporter (Choice E) are not the primary pathophysiological mechanisms in type 2 diabetes.