Knowledge Checks | South University | 26/27 (PDF)
1. A 54-year-old patient with type 2 diabetes has a hemoglobin A1c of 9.2%. Which pathophysiologic
mechanism best explains the chronic hyperglycemia in this condition?
A) Autoimmune destruction of pancreatic beta cells
B) Insulin resistance and progressive beta-cell dysfunction
C) Excessive glucagon-like peptide-1 secretion
D) Increased insulin receptor sensitivity
Correct Answer: Insulin resistance and progressive beta-cell dysfunction
Rationale: Type 2 diabetes is characterized by insulin resistance in peripheral tissues and a progressive
decline in pancreatic beta-cell function, leading to insufficient insulin secretion to maintain
euglycemia. Autoimmune destruction of beta cells defines type 1 diabetes. Excessive GLP-1 secretion
and increased insulin sensitivity would lower glucose, not cause hyperglycemia.
2. A 28-year-old patient presents with polydipsia, polyuria, and weight loss over three weeks. Fasting
glucose is 286 mg/dL, and ketones are present in the urine. Which is the most likely diagnosis?
A) Type 1 diabetes mellitus
B) Type 2 diabetes mellitus
C) Diabetes insipidus
D) Metabolic syndrome
Correct Answer: Type 1 diabetes mellitus
Rationale: The classic triad of polydipsia, polyuria, and weight loss with ketonuria and severe
hyperglycemia in a young patient is characteristic of type 1 diabetes mellitus. Type 2 diabetes typically
presents insidiously in older, obese patients without ketosis. Diabetes insipidus causes polyuria
without hyperglycemia, and metabolic syndrome does not cause ketonuria.
,3. A patient with type 1 diabetes is found unresponsive with a blood glucose of 42 mg/dL. Which
counter-regulatory hormone is primarily responsible for the immediate glucose-elevating response?
A) Insulin
B) Glucagon
C) Aldosterone
D) Cortisol
Correct Answer: Glucagon
Rationale: Glucagon is the primary counter-regulatory hormone that stimulates hepatic glycogenolysis
and gluconeogenesis within minutes of hypoglycemia. Insulin lowers glucose and would worsen the
condition. Aldosterone regulates sodium and potassium, and cortisol has a slower, more sustained
effect on glucose.
4. A 62-year-old patient with type 2 diabetes on metformin presents with fatigue and a serum
creatinine of 2.8 mg/dL. Which complication is most concerning?
A) Lactic acidosis
B) Hypoglycemia
C) Diabetic ketoacidosis
D) Hyperosmolar hyperglycemic state
Correct Answer: Lactic acidosis
Rationale: Metformin is contraindicated in renal insufficiency because impaired clearance leads to
accumulation and risk of lactic acidosis, a life-threatening complication. Metformin does not typically
cause hypoglycemia when used alone. Diabetic ketoacidosis is more common in type 1 diabetes, and
hyperosmolar hyperglycemic state is associated with severe hyperglycemia without metformin as the
primary trigger.
5. A patient with diabetic ketoacidosis has a pH of 7.18 and a bicarbonate of 10 mEq/L. Which
compensatory mechanism is expected?
A) Hyperventilation with decreased PaCO2
, B) Hypoventilation with increased PaCO2
C) Renal retention of hydrogen ions
D) Increased renal bicarbonate excretion
Correct Answer: Hyperventilation with decreased PaCO2
Rationale: In metabolic acidosis, the respiratory system compensates by hyperventilating to blow off
carbon dioxide, decreasing PaCO2 and raising pH. Hypoventilation would worsen acidosis. Renal
retention of hydrogen ions and increased bicarbonate excretion would also worsen the acid-base
disturbance.
6. Which microvascular complication of diabetes is characterized by glomerular basement membrane
thickening and mesangial expansion?
A) Diabetic neuropathy
B) Diabetic retinopathy
C) Diabetic nephropathy
D) Diabetic dermopathy
Correct Answer: Diabetic nephropathy
Rationale: Diabetic nephropathy involves thickening of the glomerular basement membrane and
mesangial expansion, leading to proteinuria and progressive renal failure. Diabetic neuropathy affects
peripheral nerves, diabetic retinopathy affects the retina, and diabetic dermopathy causes skin
lesions. Recognizing this microvascular complication is critical for renal protection.
7. A patient with type 2 diabetes has a BMI of 36 kg/m². Which pathophysiologic link best explains the
relationship between obesity and insulin resistance?
A) Increased adiponectin secretion
B) Release of free fatty acids and inflammatory cytokines from adipose tissue
C) Enhanced glucose uptake by skeletal muscle
D) Reduced hepatic gluconeogenesis