, NR 507 Advanced Pathophysiology:
Week 5 High-Yield Questions, Answers,
and Rationales 2026/2027 Update
Question 1: Endocrine Pathophysiology - Syndrome of
Inappropriate Antidiuretic Hormone Secretion Which laboratory
abnormality is most characteristic of the syndrome of
inappropriate antidiuretic hormone secretion?
A. Decreased serum osmolality with concurrent
hyponatremia
B. Elevated serum osmolality with hypernatremia
C. Decreased urine osmolality with polyuria
D. Elevated serum sodium and decreased urine sodium
concentration
Correct Answer: A. Decreased serum osmolality with concurrent
hyponatremia
Explanation: Excess antidiuretic hormone promotes continuous
water reabsorption within the renal collecting ducts, expanding
extracellular fluid volume and diluting serum solutes, which
leads to hypoosmolality and hyponatremia.
Question 2: Endocrine Pathophysiology - Diabetes Insipidus
What primary pathological mechanism distinguishes central
diabetes insipidus from nephrogenic diabetes insipidus?
A. Central diabetes insipidus involves insufficient synthesis
or release of antidiuretic hormone from the posterior
pituitary, whereas nephrogenic diabetes insipidus involves
, inadequate renal tubular responsiveness to normal
circulating hormone levels.
B. Central diabetes insipidus is caused by primary
autoimmune destruction of the adrenal cortex, whereas
nephrogenic diabetes insipidus stems from pancreatic beta
cell failure.
C. Central diabetes insipidus results from excessive water
intake, whereas nephrogenic diabetes insipidus involves
primary mineralocorticoid excess.
D. There are no physiological differences between the two
conditions.
Correct Answer: A. Central diabetes insipidus involves
insufficient synthesis or release of antidiuretic hormone from the
posterior pituitary, whereas nephrogenic diabetes insipidus
involves inadequate renal tubular responsiveness to normal
circulating hormone levels.
Explanation: Central diabetes insipidus stems from
hypothalamic or posterior pituitary lesions reducing antidiuretic
hormone production. Nephrogenic diabetes insipidus occurs
when renal tubules fail to respond to the hormone due to
acquired or genetic defects in renal V2 receptors or aquaporin
channels.
Question 3: Endocrine Pathophysiology - Diabetic Ketoacidosis
What primary metabolic alterations characterize diabetic
ketoacidosis resulting from absolute insulin deficiency?
A. Hyperglycemia, high anion gap metabolic acidosis, and
ketonemia driven by uninhibited lipolysis and hepatic
gluconeogenesis
, B. Hypoglycemia, metabolic alkalosis, and hyperkalemia
C. Normal blood glucose with primary hypercalcemia and
respiratory alkalosis
D. Lactic acidosis occurring independently of ketone body
production or insulin levels
Correct Answer: A. Hyperglycemia, high anion gap metabolic
acidosis, and ketonemia driven by uninhibited lipolysis and
hepatic gluconeogenesis
Explanation: Absolute insulin deficiency deprives cells of
glucose and removes suppression on hormone-sensitive lipase.
This triggers massive lipolysis, flooding the liver with free fatty
acids that are converted into acidic ketone bodies, producing a
high anion gap metabolic acidosis alongside osmotic diuresis
and hyperglycemia.
Question 4: Endocrine Pathophysiology - Graves Disease What
is the underlying autoimmune mechanism responsible for
Graves disease?
A. Circulating thyroid-stimulating immunoglobulins bind
to and activate thyrotropin receptors on thyroid follicular
cells, stimulating unregulated hormone synthesis.
B. Autoimmune destruction and apoptotic depletion of all
thyroid follicular cells by cytotoxic T lymphocytes.
C. Direct bacterial infection and suppurative necrosis of the
thyroid gland capsule.
D. Pituitary adenoma oversecreting thyroid-releasing
hormone without feedback inhibition.
Week 5 High-Yield Questions, Answers,
and Rationales 2026/2027 Update
Question 1: Endocrine Pathophysiology - Syndrome of
Inappropriate Antidiuretic Hormone Secretion Which laboratory
abnormality is most characteristic of the syndrome of
inappropriate antidiuretic hormone secretion?
A. Decreased serum osmolality with concurrent
hyponatremia
B. Elevated serum osmolality with hypernatremia
C. Decreased urine osmolality with polyuria
D. Elevated serum sodium and decreased urine sodium
concentration
Correct Answer: A. Decreased serum osmolality with concurrent
hyponatremia
Explanation: Excess antidiuretic hormone promotes continuous
water reabsorption within the renal collecting ducts, expanding
extracellular fluid volume and diluting serum solutes, which
leads to hypoosmolality and hyponatremia.
Question 2: Endocrine Pathophysiology - Diabetes Insipidus
What primary pathological mechanism distinguishes central
diabetes insipidus from nephrogenic diabetes insipidus?
A. Central diabetes insipidus involves insufficient synthesis
or release of antidiuretic hormone from the posterior
pituitary, whereas nephrogenic diabetes insipidus involves
, inadequate renal tubular responsiveness to normal
circulating hormone levels.
B. Central diabetes insipidus is caused by primary
autoimmune destruction of the adrenal cortex, whereas
nephrogenic diabetes insipidus stems from pancreatic beta
cell failure.
C. Central diabetes insipidus results from excessive water
intake, whereas nephrogenic diabetes insipidus involves
primary mineralocorticoid excess.
D. There are no physiological differences between the two
conditions.
Correct Answer: A. Central diabetes insipidus involves
insufficient synthesis or release of antidiuretic hormone from the
posterior pituitary, whereas nephrogenic diabetes insipidus
involves inadequate renal tubular responsiveness to normal
circulating hormone levels.
Explanation: Central diabetes insipidus stems from
hypothalamic or posterior pituitary lesions reducing antidiuretic
hormone production. Nephrogenic diabetes insipidus occurs
when renal tubules fail to respond to the hormone due to
acquired or genetic defects in renal V2 receptors or aquaporin
channels.
Question 3: Endocrine Pathophysiology - Diabetic Ketoacidosis
What primary metabolic alterations characterize diabetic
ketoacidosis resulting from absolute insulin deficiency?
A. Hyperglycemia, high anion gap metabolic acidosis, and
ketonemia driven by uninhibited lipolysis and hepatic
gluconeogenesis
, B. Hypoglycemia, metabolic alkalosis, and hyperkalemia
C. Normal blood glucose with primary hypercalcemia and
respiratory alkalosis
D. Lactic acidosis occurring independently of ketone body
production or insulin levels
Correct Answer: A. Hyperglycemia, high anion gap metabolic
acidosis, and ketonemia driven by uninhibited lipolysis and
hepatic gluconeogenesis
Explanation: Absolute insulin deficiency deprives cells of
glucose and removes suppression on hormone-sensitive lipase.
This triggers massive lipolysis, flooding the liver with free fatty
acids that are converted into acidic ketone bodies, producing a
high anion gap metabolic acidosis alongside osmotic diuresis
and hyperglycemia.
Question 4: Endocrine Pathophysiology - Graves Disease What
is the underlying autoimmune mechanism responsible for
Graves disease?
A. Circulating thyroid-stimulating immunoglobulins bind
to and activate thyrotropin receptors on thyroid follicular
cells, stimulating unregulated hormone synthesis.
B. Autoimmune destruction and apoptotic depletion of all
thyroid follicular cells by cytotoxic T lymphocytes.
C. Direct bacterial infection and suppurative necrosis of the
thyroid gland capsule.
D. Pituitary adenoma oversecreting thyroid-releasing
hormone without feedback inhibition.
