NSG 3280 Pathophysiology 1 ACTUAL
EXAM 2026/2027 | Exam 4 Practice Test
| Pathophysiology | Verified Q&A | Pass
Guaranteed - A+ Graded
SECTION 1: ENDOCRINE SYSTEM
PATHOPHYSIOLOGY (Questions 1-40)
Q1: A 45-year-old male presents with polyuria (8-10 L/day), polydipsia, and dilute urine with specific
gravity of 1.002. His fasting blood glucose is 92 mg/dL. Which pathophysiological mechanism best
explains these findings?
A. Autoimmune destruction of pancreatic beta cells resulting in insulin deficiency
B. Deficiency or resistance to antidiuretic hormone (ADH) at the renal collecting ducts
C. Excessive cortisol production causing increased glomerular filtration rate
D. Hypersecretion of growth hormone causing osmotic diuresis
Correct Answer: B
Rationale: This patient presents with diabetes insipidus (DI), characterized by polyuria with dilute
urine (specific gravity <1.005) and polydipsia despite normal blood glucose. The pathophysiology
involves either central DI (insufficient ADH production from posterior pituitary) or nephrogenic DI
(renal tubular resistance to ADH). ADH normally binds to V2 receptors on collecting duct principal
,cells, activating aquaporin-2 channels to promote water reabsorption. Without functional ADH
activity, free water cannot be reabsorbed, resulting in massive diuresis of dilute urine. The normal
blood glucose rules out diabetes mellitus as the cause of polyuria.
NSG 3280 Note: Distinguish diabetes insipidus (dilute urine, normal glucose) from diabetes mellitus
(osmotic diuresis with hyperglycemia). The water deprivation test and response to desmopressin
differentiate central from nephrogenic DI.
Q2: A patient with small cell lung cancer develops hyponatremia (Na+ 118 mEq/L), decreased serum
osmolality (260 mOsm/kg), and inappropriately concentrated urine (osmolality 450 mOsm/kg).
Which hormone is responsible for this pathophysiology?
A. Excessive antidiuretic hormone (ADH) secretion
B. Deficient aldosterone production
C. Excessive atrial natriuretic peptide (ANP) release
D. Deficient parathyroid hormone secretion
Correct Answer: A
Rationale: This presentation is classic syndrome of inappropriate antidiuretic hormone (SIADH), a
paraneoplastic syndrome commonly associated with small cell lung cancer. Ectopic ADH production
from tumor cells causes excessive water reabsorption in renal collecting ducts via aquaporin-2
channels. This results in dilutional hyponatremia with serum hypoosmolality but inappropriately
concentrated urine (urine osmolality >100 mOsm/kg despite serum hypoosmolality). The
pathophysiology involves inappropriate water retention expanding extracellular fluid volume,
triggering natriuresis despite hyponatremia.
NSG 3280 Note: SIADH diagnostic criteria: hypoosmolar hyponatremia, inappropriately concentrated
urine, clinical euvolemia, and absence of thyroid/adrenal/renal dysfunction or diuretic use.
Q3: Which of the following are clinical manifestations of panhypopituitarism? Select all that apply.
,A. Hypothyroidism due to deficient TSH
B. Adrenal insufficiency due to deficient ACTH
C. Hyperpigmentation of skin and mucous membranes
D. Growth failure in children due to deficient GH
E. Hypogonadism due to deficient FSH/LH
F. Diabetes insipidus due to deficient ADH
Correct Answers: A, B, D, E, F
Rationale: Panhypopituitarism involves deficiency of multiple anterior and/or posterior pituitary
hormones. A is correct: TSH deficiency causes secondary hypothyroidism. B is correct: ACTH
deficiency causes secondary adrenal insufficiency (cortisol deficiency without mineralocorticoid
deficiency since aldosterone is primarily regulated by RAAS). C is incorrect: hyperpigmentation occurs
in primary adrenal insufficiency (Addison's) due to elevated ACTH with MSH activity; secondary
adrenal insufficiency from pituitary failure shows no hyperpigmentation. D is correct: GH deficiency
causes growth failure in children. E is correct: gonadotropin deficiency causes hypogonadism. F is
correct: posterior pituitary involvement causes diabetes insipidus from ADH deficiency.
NSG 3280 Note: Secondary adrenal insufficiency (pituitary origin) spares mineralocorticoid
function—no hyperkalemia or salt-wasting crises as seen in primary Addison's disease.
Q4: A 32-year-old female presents with weight loss, heat intolerance, tremor, exophthalmos, and
pretibial myxedema. Laboratory studies show elevated free T4, decreased TSH, and positive TSH
receptor antibodies. Which pathophysiological process is occurring?
A. Autoimmune stimulation of TSH receptors causing hyperthyroidism
B. Autoimmune destruction of thyroid tissue causing hypothyroidism
C. Pituitary adenoma secreting excessive TSH
D. Iodine deficiency causing compensatory thyroid enlargement
, Correct Answer: A
Rationale: This presentation is classic Graves' disease, an autoimmune disorder where IgG antibodies
(thyroid-stimulating immunoglobulins/TSI) bind to and activate TSH receptors on thyroid follicular
cells. This stimulates excessive synthesis and release of T3/T4 independent of TSH control, causing
hyperthyroidism with suppressed pituitary TSH. The extrathyroidal manifestations (exophthalmos
from orbital fibroblast activation and glycosaminoglycan deposition; pretibial myxedema from
dermal glycosaminoglycan accumulation) result from TSI cross-reactivity with antigens in orbital and
dermal fibroblasts.
NSG 3280 Note: Graves' disease is the most common cause of hyperthyroidism. TSH receptor
antibodies are pathognomonic. Exophthalmos may persist or worsen even after thyroid function
normalizes.
Q5: A patient with Hashimoto's thyroiditis develops progressive thyroid enlargement and
hypothyroidism. Which pathophysiological mechanism underlies this autoimmune disorder?
A. TSH receptor stimulation by autoantibodies
B. Cytotoxic T-cell mediated destruction of thyroid follicular cells
C. Iodine-induced inhibition of thyroid hormone synthesis
D. Viral infection causing direct thyroid cell lysis
Correct Answer: B
Rationale: Hashimoto's thyroiditis (chronic lymphocytic thyroiditis) is an organ-specific autoimmune
disease characterized by cell-mediated destruction of thyroid tissue. Cytotoxic T-cells (CD8+) directly
attack thyroid follicular cells, while T-helper cells (CD4+) recruit inflammatory infiltrate and stimulate
B-cell production of antithyroid antibodies (anti-TPO, anti-thyroglobulin). Progressive destruction
leads to fibrosis, goiter formation (lymphocytic infiltration), and eventual hypothyroidism. The
pathophysiology involves loss of self-tolerance with Th1 immune response predominance.
NSG 3280 Note: Hashimoto's is the most common cause of hypothyroidism in iodine-sufficient
regions. High titers of anti-thyroid peroxidase (anti-TPO) antibodies are diagnostic markers.
EXAM 2026/2027 | Exam 4 Practice Test
| Pathophysiology | Verified Q&A | Pass
Guaranteed - A+ Graded
SECTION 1: ENDOCRINE SYSTEM
PATHOPHYSIOLOGY (Questions 1-40)
Q1: A 45-year-old male presents with polyuria (8-10 L/day), polydipsia, and dilute urine with specific
gravity of 1.002. His fasting blood glucose is 92 mg/dL. Which pathophysiological mechanism best
explains these findings?
A. Autoimmune destruction of pancreatic beta cells resulting in insulin deficiency
B. Deficiency or resistance to antidiuretic hormone (ADH) at the renal collecting ducts
C. Excessive cortisol production causing increased glomerular filtration rate
D. Hypersecretion of growth hormone causing osmotic diuresis
Correct Answer: B
Rationale: This patient presents with diabetes insipidus (DI), characterized by polyuria with dilute
urine (specific gravity <1.005) and polydipsia despite normal blood glucose. The pathophysiology
involves either central DI (insufficient ADH production from posterior pituitary) or nephrogenic DI
(renal tubular resistance to ADH). ADH normally binds to V2 receptors on collecting duct principal
,cells, activating aquaporin-2 channels to promote water reabsorption. Without functional ADH
activity, free water cannot be reabsorbed, resulting in massive diuresis of dilute urine. The normal
blood glucose rules out diabetes mellitus as the cause of polyuria.
NSG 3280 Note: Distinguish diabetes insipidus (dilute urine, normal glucose) from diabetes mellitus
(osmotic diuresis with hyperglycemia). The water deprivation test and response to desmopressin
differentiate central from nephrogenic DI.
Q2: A patient with small cell lung cancer develops hyponatremia (Na+ 118 mEq/L), decreased serum
osmolality (260 mOsm/kg), and inappropriately concentrated urine (osmolality 450 mOsm/kg).
Which hormone is responsible for this pathophysiology?
A. Excessive antidiuretic hormone (ADH) secretion
B. Deficient aldosterone production
C. Excessive atrial natriuretic peptide (ANP) release
D. Deficient parathyroid hormone secretion
Correct Answer: A
Rationale: This presentation is classic syndrome of inappropriate antidiuretic hormone (SIADH), a
paraneoplastic syndrome commonly associated with small cell lung cancer. Ectopic ADH production
from tumor cells causes excessive water reabsorption in renal collecting ducts via aquaporin-2
channels. This results in dilutional hyponatremia with serum hypoosmolality but inappropriately
concentrated urine (urine osmolality >100 mOsm/kg despite serum hypoosmolality). The
pathophysiology involves inappropriate water retention expanding extracellular fluid volume,
triggering natriuresis despite hyponatremia.
NSG 3280 Note: SIADH diagnostic criteria: hypoosmolar hyponatremia, inappropriately concentrated
urine, clinical euvolemia, and absence of thyroid/adrenal/renal dysfunction or diuretic use.
Q3: Which of the following are clinical manifestations of panhypopituitarism? Select all that apply.
,A. Hypothyroidism due to deficient TSH
B. Adrenal insufficiency due to deficient ACTH
C. Hyperpigmentation of skin and mucous membranes
D. Growth failure in children due to deficient GH
E. Hypogonadism due to deficient FSH/LH
F. Diabetes insipidus due to deficient ADH
Correct Answers: A, B, D, E, F
Rationale: Panhypopituitarism involves deficiency of multiple anterior and/or posterior pituitary
hormones. A is correct: TSH deficiency causes secondary hypothyroidism. B is correct: ACTH
deficiency causes secondary adrenal insufficiency (cortisol deficiency without mineralocorticoid
deficiency since aldosterone is primarily regulated by RAAS). C is incorrect: hyperpigmentation occurs
in primary adrenal insufficiency (Addison's) due to elevated ACTH with MSH activity; secondary
adrenal insufficiency from pituitary failure shows no hyperpigmentation. D is correct: GH deficiency
causes growth failure in children. E is correct: gonadotropin deficiency causes hypogonadism. F is
correct: posterior pituitary involvement causes diabetes insipidus from ADH deficiency.
NSG 3280 Note: Secondary adrenal insufficiency (pituitary origin) spares mineralocorticoid
function—no hyperkalemia or salt-wasting crises as seen in primary Addison's disease.
Q4: A 32-year-old female presents with weight loss, heat intolerance, tremor, exophthalmos, and
pretibial myxedema. Laboratory studies show elevated free T4, decreased TSH, and positive TSH
receptor antibodies. Which pathophysiological process is occurring?
A. Autoimmune stimulation of TSH receptors causing hyperthyroidism
B. Autoimmune destruction of thyroid tissue causing hypothyroidism
C. Pituitary adenoma secreting excessive TSH
D. Iodine deficiency causing compensatory thyroid enlargement
, Correct Answer: A
Rationale: This presentation is classic Graves' disease, an autoimmune disorder where IgG antibodies
(thyroid-stimulating immunoglobulins/TSI) bind to and activate TSH receptors on thyroid follicular
cells. This stimulates excessive synthesis and release of T3/T4 independent of TSH control, causing
hyperthyroidism with suppressed pituitary TSH. The extrathyroidal manifestations (exophthalmos
from orbital fibroblast activation and glycosaminoglycan deposition; pretibial myxedema from
dermal glycosaminoglycan accumulation) result from TSI cross-reactivity with antigens in orbital and
dermal fibroblasts.
NSG 3280 Note: Graves' disease is the most common cause of hyperthyroidism. TSH receptor
antibodies are pathognomonic. Exophthalmos may persist or worsen even after thyroid function
normalizes.
Q5: A patient with Hashimoto's thyroiditis develops progressive thyroid enlargement and
hypothyroidism. Which pathophysiological mechanism underlies this autoimmune disorder?
A. TSH receptor stimulation by autoantibodies
B. Cytotoxic T-cell mediated destruction of thyroid follicular cells
C. Iodine-induced inhibition of thyroid hormone synthesis
D. Viral infection causing direct thyroid cell lysis
Correct Answer: B
Rationale: Hashimoto's thyroiditis (chronic lymphocytic thyroiditis) is an organ-specific autoimmune
disease characterized by cell-mediated destruction of thyroid tissue. Cytotoxic T-cells (CD8+) directly
attack thyroid follicular cells, while T-helper cells (CD4+) recruit inflammatory infiltrate and stimulate
B-cell production of antithyroid antibodies (anti-TPO, anti-thyroglobulin). Progressive destruction
leads to fibrosis, goiter formation (lymphocytic infiltration), and eventual hypothyroidism. The
pathophysiology involves loss of self-tolerance with Th1 immune response predominance.
NSG 3280 Note: Hashimoto's is the most common cause of hypothyroidism in iodine-sufficient
regions. High titers of anti-thyroid peroxidase (anti-TPO) antibodies are diagnostic markers.
