, Question 1
A patient with chronic heart failure has a BNP of 1200 pg/mL and an
echocardiogram showing an ejection fraction of 35%. Which pathophysiologic
mechanism best explains the elevated BNP?
A. Increased ventricular preload causing atrial natriuretic peptide release
B. Ventricular myocyte stretch due to elevated filling pressures
C. Renal hypoperfusion stimulating erythropoietin production
D. Systemic vasodilation reducing afterload and increasing BNP
clearance
Correct Answer: B - Ventricular myocyte stretch due to elevated
filling pressures
RATIONALE
BNP is released primarily from ventricular myocytes in response to
wall stretch from elevated filling pressures (preload) and volume
overload. Atrial natriuretic peptide (ANP) is mainly atrial, and
erythropoietin is unrelated. Vasodilation would not directly increase
BNP; it may reduce stretch.
Question 2
Which arterial blood gas pattern is most consistent with acute respiratory
distress syndrome (ARDS) in its early exudative phase?
A. pH 7.48, PaCO2 30, HCO3 22, PaO2 55 on room air
B. pH 7.30, PaCO2 55, HCO3 26, PaO2 80 on room air
C. pH 7.38, PaCO2 40, HCO3 24, PaO2 90 on room air
D. pH 7.25, PaCO2 35, HCO3 15, PaO2 70 on room air
Correct Answer: A - pH 7.48, PaCO2 30, HCO3 22, PaO2 55 on
room air
Page 2
, RATIONALE
Early ARDS causes refractory hypoxemia (PaO2 <60) and respiratory
alkalosis from hyperventilation (low PaCO2, elevated pH). Option B
reflects hypoventilation, C is normal, and D suggests metabolic
acidosis with respiratory compensation, not typical early ARDS.
Question 3
A patient with diabetic nephropathy has a glomerular filtration rate of 45
mL/min/1.73 m² and proteinuria. Which pathophysiologic change is most
directly responsible for the proteinuria?
A. Increased glomerular capillary permeability due to podocyte injury
B. Decreased tubular reabsorption of filtered proteins
C. Reduced renal plasma flow causing ischemic tubular damage
D. Elevated serum protein concentration overwhelming filtration
Correct Answer: A - Increased glomerular capillary permeability
due to podocyte injury
RATIONALE
Proteinuria in diabetic nephropathy results from damage to the
glomerular filtration barrier, particularly podocyte injury and loss of
negative charge, increasing permeability to proteins. Tubular
reabsorption defects can cause low-molecular-weight proteinuria but
are not the primary mechanism here. Hyperproteinemia rarely causes
proteinuria.
Question 4
Which statement best describes the role of hepatic stellate cells in the
progression of cirrhosis?
A. They transform into myofibroblasts and produce excessive collagen
B. They store vitamin A and prevent fibrosis
C. They are the primary site of ammonia detoxification
D. They phagocytose senescent red blood cells
Page 3
, Correct Answer: A - They transform into myofibroblasts and
produce excessive collagen
RATIONALE
Hepatic stellate cells, when activated by injury, transdifferentiate into
myofibroblasts and secrete collagen, leading to fibrosis and cirrhosis.
Their normal function includes vitamin A storage, but activation
promotes fibrosis. Ammonia detoxification occurs via urea cycle in
hepatocytes, and Kupffer cells phagocytose RBCs.
Question 5
In a patient with syndrome of inappropriate antidiuretic hormone (SIADH),
which laboratory finding is expected?
A. Serum osmolality <275 mOsm/kg and urine osmolality >100
mOsm/kg
B. Serum osmolality >295 mOsm/kg and urine osmolality <100
mOsm/kg
C. Serum sodium >145 mEq/L and urine sodium <10 mEq/L
D. Serum potassium >5.5 mEq/L and metabolic alkalosis
Correct Answer: A - Serum osmolality <275 mOsm/kg and urine
osmolality >100 mOsm/kg
RATIONALE
SIADH is characterized by hypotonic hyponatremia (serum osmolality
<275) with inappropriately concentrated urine (urine osmolality
>100). Option B describes diabetes insipidus. Hypernatremia and
hyperkalemia are not typical of SIADH.
Question 6
Which mechanism explains the development of metabolic alkalosis in a patient
with prolonged vomiting?
A. Loss of hydrogen ions and chloride in gastric fluid
Page 4
A patient with chronic heart failure has a BNP of 1200 pg/mL and an
echocardiogram showing an ejection fraction of 35%. Which pathophysiologic
mechanism best explains the elevated BNP?
A. Increased ventricular preload causing atrial natriuretic peptide release
B. Ventricular myocyte stretch due to elevated filling pressures
C. Renal hypoperfusion stimulating erythropoietin production
D. Systemic vasodilation reducing afterload and increasing BNP
clearance
Correct Answer: B - Ventricular myocyte stretch due to elevated
filling pressures
RATIONALE
BNP is released primarily from ventricular myocytes in response to
wall stretch from elevated filling pressures (preload) and volume
overload. Atrial natriuretic peptide (ANP) is mainly atrial, and
erythropoietin is unrelated. Vasodilation would not directly increase
BNP; it may reduce stretch.
Question 2
Which arterial blood gas pattern is most consistent with acute respiratory
distress syndrome (ARDS) in its early exudative phase?
A. pH 7.48, PaCO2 30, HCO3 22, PaO2 55 on room air
B. pH 7.30, PaCO2 55, HCO3 26, PaO2 80 on room air
C. pH 7.38, PaCO2 40, HCO3 24, PaO2 90 on room air
D. pH 7.25, PaCO2 35, HCO3 15, PaO2 70 on room air
Correct Answer: A - pH 7.48, PaCO2 30, HCO3 22, PaO2 55 on
room air
Page 2
, RATIONALE
Early ARDS causes refractory hypoxemia (PaO2 <60) and respiratory
alkalosis from hyperventilation (low PaCO2, elevated pH). Option B
reflects hypoventilation, C is normal, and D suggests metabolic
acidosis with respiratory compensation, not typical early ARDS.
Question 3
A patient with diabetic nephropathy has a glomerular filtration rate of 45
mL/min/1.73 m² and proteinuria. Which pathophysiologic change is most
directly responsible for the proteinuria?
A. Increased glomerular capillary permeability due to podocyte injury
B. Decreased tubular reabsorption of filtered proteins
C. Reduced renal plasma flow causing ischemic tubular damage
D. Elevated serum protein concentration overwhelming filtration
Correct Answer: A - Increased glomerular capillary permeability
due to podocyte injury
RATIONALE
Proteinuria in diabetic nephropathy results from damage to the
glomerular filtration barrier, particularly podocyte injury and loss of
negative charge, increasing permeability to proteins. Tubular
reabsorption defects can cause low-molecular-weight proteinuria but
are not the primary mechanism here. Hyperproteinemia rarely causes
proteinuria.
Question 4
Which statement best describes the role of hepatic stellate cells in the
progression of cirrhosis?
A. They transform into myofibroblasts and produce excessive collagen
B. They store vitamin A and prevent fibrosis
C. They are the primary site of ammonia detoxification
D. They phagocytose senescent red blood cells
Page 3
, Correct Answer: A - They transform into myofibroblasts and
produce excessive collagen
RATIONALE
Hepatic stellate cells, when activated by injury, transdifferentiate into
myofibroblasts and secrete collagen, leading to fibrosis and cirrhosis.
Their normal function includes vitamin A storage, but activation
promotes fibrosis. Ammonia detoxification occurs via urea cycle in
hepatocytes, and Kupffer cells phagocytose RBCs.
Question 5
In a patient with syndrome of inappropriate antidiuretic hormone (SIADH),
which laboratory finding is expected?
A. Serum osmolality <275 mOsm/kg and urine osmolality >100
mOsm/kg
B. Serum osmolality >295 mOsm/kg and urine osmolality <100
mOsm/kg
C. Serum sodium >145 mEq/L and urine sodium <10 mEq/L
D. Serum potassium >5.5 mEq/L and metabolic alkalosis
Correct Answer: A - Serum osmolality <275 mOsm/kg and urine
osmolality >100 mOsm/kg
RATIONALE
SIADH is characterized by hypotonic hyponatremia (serum osmolality
<275) with inappropriately concentrated urine (urine osmolality
>100). Option B describes diabetes insipidus. Hypernatremia and
hyperkalemia are not typical of SIADH.
Question 6
Which mechanism explains the development of metabolic alkalosis in a patient
with prolonged vomiting?
A. Loss of hydrogen ions and chloride in gastric fluid
Page 4
