NR 603 APEA 3P FINAL EXAM QUESTIONS
AND ANSWERS
SECTION 1: ADVANCED PATHOPHYSIOLOGY
Question 1
A 62-year-old male with a 50-pack-year smoking history presents with progressive dyspnea on
exertion, chronic productive cough, and wheezing. Spirometry reveals an FEV1/FVC ratio of 0.58
and post-bronchodilator FEV1 of 48% predicted. Which pathophysiologic process is most
responsible for this patient's airflow limitation?
A. Reversible bronchoconstriction mediated by IgE
B. Irreversible small airway fibrosis and loss of elastic recoil
C. Autoimmune destruction of alveolar basement membrane
D. Increased pulmonary vascular resistance
Correct Answer: B
Rationale: This presentation is classic for COPD, characterized by irreversible airflow
obstruction. The fixed FEV1/FVC ratio below 0.70 that does not fully reverse with
bronchodilators confirms this. Pathophysiologically, COPD involves chronic bronchitis (small
airway fibrosis, mucus hypersecretion) and emphysema (alveolar destruction with loss of elastic
recoil) . Option A describes asthma. Option C describes Goodpasture syndrome. Option D
describes pulmonary hypertension.
Question 2
A 28-year-old female presents with fatigue, pallor, and jaundice. Laboratory studies show
hemoglobin 7.2 g/dL, elevated reticulocyte count, elevated indirect bilirubin, and a positive
direct antiglobulin (Coombs) test. Which type of hypersensitivity reaction is responsible for this
patient's anemia?
A. Type I (IgE-mediated)
B. Type II (antibody-mediated)
C. Type III (immune complex-mediated)
D. Type IV (cell-mediated)
Correct Answer: B
, Rationale: The positive Coombs test indicates antibodies are attached to the patient's own
red blood cells, leading to their destruction—this is autoimmune hemolytic anemia, a Type II
hypersensitivity reaction . Type II reactions involve IgG or IgM antibodies directed against
antigens on the cell surface. Type I is immediate hypersensitivity (allergy). Type III involves
circulating immune complexes (e.g., SLE nephritis). Type IV is delayed hypersensitivity (e.g.,
contact dermatitis).
Question 3
A 55-year-old male with a history of alcohol use disorder presents to the emergency
department after a witnessed generalized tonic-clonic seizure. His serum sodium is 110 mEq/L.
When correcting this patient's sodium, what is the maximum recommended rate of correction
in the first 24 hours to prevent osmotic demyelination syndrome?
A. 6 mEq/L
B. 8-10 mEq/L
C. 15-20 mEq/L
D. 25 mEq/L
Correct Answer: B
Rationale: Severe hyponatremia (<120 mEq/L) with neurologic symptoms requires careful
correction. The maximum recommended rate is 8-10 mEq/L in the first 24 hours (or 1-2 mEq/L
per hour) to prevent osmotic demyelination syndrome (central pontine myelinolysis) . Overly
rapid correction can cause severe and irreversible neurologic damage. The seizure should be
treated acutely with benzodiazepines while sodium is corrected cautiously.
Question 4
A 45-year-old female presents with fatigue, weight gain, cold intolerance, and constipation.
Laboratory testing reveals elevated TSH and low free T4. Which pathophysiologic mechanism
best explains these findings?
A. Autoimmune destruction of thyroid gland
B. Excessive thyroid hormone production
C. Pituitary adenoma producing excess TSH
D. Iodine deficiency
Correct Answer: A
, Rationale: The elevated TSH with low free T4 indicates primary hypothyroidism. In
developed countries, the most common cause is Hashimoto's thyroiditis, an autoimmune
condition characterized by lymphocytic infiltration and destruction of thyroid follicles . Option B
describes hyperthyroidism. Option C describes secondary hyperthyroidism (rare). Option D is a
less common cause of hypothyroidism in iodine-sufficient regions.
Question 5
A 58-year-old male with longstanding hypertension presents with progressive dyspnea on
exertion, orthopnea, and bilateral lower extremity edema. Echocardiography shows left
ventricular hypertrophy with an ejection fraction of 55% and elevated filling pressures. Which
pathophysiologic mechanism primarily accounts for his symptoms?
A. Systolic dysfunction with reduced stroke volume
B. Diastolic dysfunction with impaired ventricular relaxation
C. Primary right ventricular failure
D. High-output heart failure from chronic anemia
Correct Answer: B
Rationale: The preserved ejection fraction (>50%) with signs and symptoms of heart failure
indicates heart failure with preserved ejection fraction (HFpEF). The underlying mechanism is
diastolic dysfunction—impaired ventricular relaxation and increased stiffness, which raises left
ventricular end-diastolic pressure and causes pulmonary congestion despite normal systolic
function . Chronic hypertension is the most common cause of LVH and diastolic dysfunction.
Question 6
A 35-year-old male with chronic hepatitis C develops cirrhosis. Laboratory studies show
decreased albumin, prolonged PT/INR, and elevated ammonia. Which hepatic functional deficit
best explains the elevated ammonia?
A. Impaired bile acid synthesis
B. Decreased hepatocyte mass leading to impaired urea cycle function
C. Portal vein thrombosis
D. Increased hepatic blood flow
Correct Answer: B
, Rationale: The liver converts ammonia to urea via the urea cycle. In cirrhosis, loss of
functional hepatocyte mass impairs this detoxification pathway, leading to hyperammonemia .
Additionally, portosystemic shunting allows intestinal ammonia to bypass the liver. Decreased
albumin and prolonged PT/INR reflect impaired synthetic function. Bile acid synthesis is
unrelated to ammonia metabolism.
Question 7
A 67-year-old female with type 2 diabetes presents with numbness and tingling in a stocking-
glove distribution, decreased vibratory sense, and absent ankle reflexes. Which
pathophysiologic mechanism underlies these findings?
A. Demyelination of large motor neurons
B. Microvascular damage causing ischemia and oxidative stress to peripheral nerves
C. Compression of spinal nerve roots
D. Autoimmune destruction of Schwann cells
Correct Answer: B
Rationale: Diabetic peripheral neuropathy results from chronic hyperglycemia-induced
microvascular damage, accumulation of advanced glycation end products (AGEs), polyol
pathway activation, and oxidative stress—all contributing to nerve ischemia and axonal
degeneration . The stocking-glove pattern reflects the length-dependent nature of the
neuropathy. Option C describes radiculopathy. Option D describes Guillain-Barré syndrome.
Question 8
A 42-year-old female with systemic lupus erythematosus presents with proteinuria, hematuria,
and rising creatinine. Renal biopsy shows "wire loop" lesions on light microscopy. Which
immune-mediated mechanism underlies this finding?
A. Type I hypersensitivity with IgE-mediated mast cell degranulation
B. Type II hypersensitivity with antibody-mediated cytotoxicity
C. Type III hypersensitivity with immune complex deposition
D. Type IV hypersensitivity with T-cell-mediated delayed hypersensitivity
Correct Answer: C
Rationale: Lupus nephritis classically demonstrates Type III hypersensitivity, where
circulating antigen-antibody complexes deposit in the glomerular basement membrane, activate
AND ANSWERS
SECTION 1: ADVANCED PATHOPHYSIOLOGY
Question 1
A 62-year-old male with a 50-pack-year smoking history presents with progressive dyspnea on
exertion, chronic productive cough, and wheezing. Spirometry reveals an FEV1/FVC ratio of 0.58
and post-bronchodilator FEV1 of 48% predicted. Which pathophysiologic process is most
responsible for this patient's airflow limitation?
A. Reversible bronchoconstriction mediated by IgE
B. Irreversible small airway fibrosis and loss of elastic recoil
C. Autoimmune destruction of alveolar basement membrane
D. Increased pulmonary vascular resistance
Correct Answer: B
Rationale: This presentation is classic for COPD, characterized by irreversible airflow
obstruction. The fixed FEV1/FVC ratio below 0.70 that does not fully reverse with
bronchodilators confirms this. Pathophysiologically, COPD involves chronic bronchitis (small
airway fibrosis, mucus hypersecretion) and emphysema (alveolar destruction with loss of elastic
recoil) . Option A describes asthma. Option C describes Goodpasture syndrome. Option D
describes pulmonary hypertension.
Question 2
A 28-year-old female presents with fatigue, pallor, and jaundice. Laboratory studies show
hemoglobin 7.2 g/dL, elevated reticulocyte count, elevated indirect bilirubin, and a positive
direct antiglobulin (Coombs) test. Which type of hypersensitivity reaction is responsible for this
patient's anemia?
A. Type I (IgE-mediated)
B. Type II (antibody-mediated)
C. Type III (immune complex-mediated)
D. Type IV (cell-mediated)
Correct Answer: B
, Rationale: The positive Coombs test indicates antibodies are attached to the patient's own
red blood cells, leading to their destruction—this is autoimmune hemolytic anemia, a Type II
hypersensitivity reaction . Type II reactions involve IgG or IgM antibodies directed against
antigens on the cell surface. Type I is immediate hypersensitivity (allergy). Type III involves
circulating immune complexes (e.g., SLE nephritis). Type IV is delayed hypersensitivity (e.g.,
contact dermatitis).
Question 3
A 55-year-old male with a history of alcohol use disorder presents to the emergency
department after a witnessed generalized tonic-clonic seizure. His serum sodium is 110 mEq/L.
When correcting this patient's sodium, what is the maximum recommended rate of correction
in the first 24 hours to prevent osmotic demyelination syndrome?
A. 6 mEq/L
B. 8-10 mEq/L
C. 15-20 mEq/L
D. 25 mEq/L
Correct Answer: B
Rationale: Severe hyponatremia (<120 mEq/L) with neurologic symptoms requires careful
correction. The maximum recommended rate is 8-10 mEq/L in the first 24 hours (or 1-2 mEq/L
per hour) to prevent osmotic demyelination syndrome (central pontine myelinolysis) . Overly
rapid correction can cause severe and irreversible neurologic damage. The seizure should be
treated acutely with benzodiazepines while sodium is corrected cautiously.
Question 4
A 45-year-old female presents with fatigue, weight gain, cold intolerance, and constipation.
Laboratory testing reveals elevated TSH and low free T4. Which pathophysiologic mechanism
best explains these findings?
A. Autoimmune destruction of thyroid gland
B. Excessive thyroid hormone production
C. Pituitary adenoma producing excess TSH
D. Iodine deficiency
Correct Answer: A
, Rationale: The elevated TSH with low free T4 indicates primary hypothyroidism. In
developed countries, the most common cause is Hashimoto's thyroiditis, an autoimmune
condition characterized by lymphocytic infiltration and destruction of thyroid follicles . Option B
describes hyperthyroidism. Option C describes secondary hyperthyroidism (rare). Option D is a
less common cause of hypothyroidism in iodine-sufficient regions.
Question 5
A 58-year-old male with longstanding hypertension presents with progressive dyspnea on
exertion, orthopnea, and bilateral lower extremity edema. Echocardiography shows left
ventricular hypertrophy with an ejection fraction of 55% and elevated filling pressures. Which
pathophysiologic mechanism primarily accounts for his symptoms?
A. Systolic dysfunction with reduced stroke volume
B. Diastolic dysfunction with impaired ventricular relaxation
C. Primary right ventricular failure
D. High-output heart failure from chronic anemia
Correct Answer: B
Rationale: The preserved ejection fraction (>50%) with signs and symptoms of heart failure
indicates heart failure with preserved ejection fraction (HFpEF). The underlying mechanism is
diastolic dysfunction—impaired ventricular relaxation and increased stiffness, which raises left
ventricular end-diastolic pressure and causes pulmonary congestion despite normal systolic
function . Chronic hypertension is the most common cause of LVH and diastolic dysfunction.
Question 6
A 35-year-old male with chronic hepatitis C develops cirrhosis. Laboratory studies show
decreased albumin, prolonged PT/INR, and elevated ammonia. Which hepatic functional deficit
best explains the elevated ammonia?
A. Impaired bile acid synthesis
B. Decreased hepatocyte mass leading to impaired urea cycle function
C. Portal vein thrombosis
D. Increased hepatic blood flow
Correct Answer: B
, Rationale: The liver converts ammonia to urea via the urea cycle. In cirrhosis, loss of
functional hepatocyte mass impairs this detoxification pathway, leading to hyperammonemia .
Additionally, portosystemic shunting allows intestinal ammonia to bypass the liver. Decreased
albumin and prolonged PT/INR reflect impaired synthetic function. Bile acid synthesis is
unrelated to ammonia metabolism.
Question 7
A 67-year-old female with type 2 diabetes presents with numbness and tingling in a stocking-
glove distribution, decreased vibratory sense, and absent ankle reflexes. Which
pathophysiologic mechanism underlies these findings?
A. Demyelination of large motor neurons
B. Microvascular damage causing ischemia and oxidative stress to peripheral nerves
C. Compression of spinal nerve roots
D. Autoimmune destruction of Schwann cells
Correct Answer: B
Rationale: Diabetic peripheral neuropathy results from chronic hyperglycemia-induced
microvascular damage, accumulation of advanced glycation end products (AGEs), polyol
pathway activation, and oxidative stress—all contributing to nerve ischemia and axonal
degeneration . The stocking-glove pattern reflects the length-dependent nature of the
neuropathy. Option C describes radiculopathy. Option D describes Guillain-Barré syndrome.
Question 8
A 42-year-old female with systemic lupus erythematosus presents with proteinuria, hematuria,
and rising creatinine. Renal biopsy shows "wire loop" lesions on light microscopy. Which
immune-mediated mechanism underlies this finding?
A. Type I hypersensitivity with IgE-mediated mast cell degranulation
B. Type II hypersensitivity with antibody-mediated cytotoxicity
C. Type III hypersensitivity with immune complex deposition
D. Type IV hypersensitivity with T-cell-mediated delayed hypersensitivity
Correct Answer: C
Rationale: Lupus nephritis classically demonstrates Type III hypersensitivity, where
circulating antigen-antibody complexes deposit in the glomerular basement membrane, activate
