Fundamentals & Core Concepts Flashcards

Acanthosis nigricans in a patient with diabetes is a clinical marker of:

Answer: Severe insulin resistance with hyperinsulinemia

Acanthosis nigricans (velvety hyperpigmentation in skin folds) is a cutaneous sign of significant insulin resistance and chronic hyperinsulinemia.

The 'glucose toxicity' concept in type 2 diabetes refers to:

Answer: Reversible impairment of beta-cell function and insulin sensitivity caused by chronic hyperglycemia

Glucose toxicity describes how chronic hyperglycemia itself reversibly impairs both beta-cell insulin secretion and peripheral insulin sensitivity, perpetuating the hyperglycemia.

Which statement about the HbA1c test limitation is most clinically relevant for an advanced diabetes manager?

Answer: HbA1c may be falsely low in conditions that shorten red blood cell lifespan, such as hemolytic anemia

Conditions that shorten RBC lifespan (hemolytic anemia, hemoglobinopathies, recent transfusion) cause falsely low HbA1c by reducing red cell exposure time to glucose.

Insulin secretion occurs in a biphasic pattern. The first phase primarily reflects:

Answer: Release of pre-formed insulin granules docked at the beta-cell membrane

The first-phase insulin spike (within 1–3 minutes of glucose rise) represents exocytosis of a readily releasable pool of pre-docked secretory granules.

Latent autoimmune diabetes in adults (LADA) is distinguished from type 2 diabetes by:

Answer: Presence of islet autoantibodies (typically GAD65) and progressive beta-cell loss

LADA presents clinically like type 2 but is distinguished by islet autoantibodies (most commonly anti-GAD65) and inevitable progression to insulin dependence.

Which mechanism explains why patients with long-standing type 1 diabetes may lose hypoglycemia awareness?

Answer: Repeated hypoglycemia blunts sympathoadrenal responses and shifts glycemic thresholds for symptoms

Hypoglycemia-associated autonomic failure (HAAF) results from repeated hypoglycemia that reduces epinephrine and symptom responses, raising the threshold at which symptoms appear.

According to the pathophysiological 'ominous octet' described by DeFronzo, which of the following is NOT one of the eight defects contributing to type 2 diabetes hyperglycemia?

Answer: Reduced erythropoietin production by the kidney

DeFronzo's ominous octet includes defects in beta cells, alpha cells, muscle, liver, adipocytes, brain, kidney (glucose reabsorption), and gut (incretins) — erythropoietin is not part of it.