D115 OA / WGU D115 OA PREP TEST BANK 2026/2027 WITH
450 REAL EXAM QUESTIONS AND CORRECT ANSWERS
WITH RATIONALES/ WGU D115 ADVANCED
PATHOPHYSIOLOGY OA PREP(NEW!)
1. A 62-year-old male with a history of chronic obstructive pulmonary disease (COPD) presents
with increased dyspnea, productive cough, and fever. Chest radiograph reveals a new right
lower lobe infiltrate. Sputum Gram stain shows gram-positive diplococci, and blood cultures
grow Streptococcus pneumoniae. Despite appropriate antibiotic therapy, the patient develops
acute respiratory distress syndrome (ARDS). Which pathophysiologic mechanism is the
PRIMARY contributor to the development of ARDS in this patient?
A. Excessive influx of neutrophils into the alveolar space with release of reactive oxygen species and
proteases
B. Direct bacterial invasion of the alveolar epithelium leading to necrotizing pneumonia and cavitation
C. Impaired mucociliary clearance causing mucus plugging and atelectasis with subsequent shunt physiology
D. Type II pneumocyte hyperplasia resulting in increased surfactant production and alveolar stability
Answer: A. Excessive influx of neutrophils into the alveolar space with release of reactive
oxygen species and proteases
2. A 45-year-old woman with systemic lupus erythematosus (SLE) presents with fatigue, joint
pain, and a malar rash. Laboratory studies show anemia, leukopenia, and a positive
anti-double-stranded DNA (anti-dsDNA) antibody test. Which type of hypersensitivity reaction is
MOST consistent with the pathogenesis of her lupus nephritis?
A. Type II hypersensitivity mediated by antibodies against glomerular basement membrane
B. Type III hypersensitivity with immune complex deposition in the glomeruli
C. Type IV hypersensitivity mediated by T-helper 1 cells and macrophage activation
D. Type I hypersensitivity with mast cell degranulation and histamine release
Answer: B. Type III hypersensitivity with immune complex deposition in the glomeruli
3. A 70-year-old male with chronic kidney disease stage 4 has a serum creatinine of 3.5 mg/dL
and a calcium of 8.2 mg/dL (normal 8.5-10.5), phosphate of 6.0 mg/dL (normal 2.5-4.5), and an
intact parathyroid hormone (PTH) level of 250 pg/mL (normal 10-65). Which pathophysiologic
change is the MOST likely cause of the elevated PTH level in this patient?
A. Decreased renal activation of vitamin D leading to reduced intestinal calcium absorption and hypocalcemia,
stimulating PTH secretion
B. Increased renal phosphate excretion causing hypophosphatemia, which directly stimulates parathyroid
chief cells to release PTH
C. Direct toxic effect of uremic toxins on the parathyroid glands causing autonomous (tertiary)
hyperparathyroidism
D. Increased calcium-sensing receptor (CaSR) expression on parathyroid cells producing a lower set point for
PTH suppression
Answer: A. Decreased renal activation of vitamin D leading to reduced intestinal calcium
absorption and hypocalcemia, stimulating PTH secretion
4. A 55-year-old male with a history of alcohol use disorder is found to have a macrocytic
anemia. His peripheral smear shows hypersegmented neutrophils and oval macrocytes. Serum
,vitamin B12 is 150 pg/mL (normal 200-900) and folate is normal. Which pathophysiologic
mechanism is MOST responsible for the neurologic symptoms that may accompany his
anemia?
A. Deficiency of vitamin B12 leads to accumulation of methylmalonic acid, which impairs myelin synthesis in
the nervous system
B. Folate deficiency causes impaired DNA synthesis in neuronal cells leading to axonal degeneration
C. Chronic alcohol toxicity directly damages the dorsal columns and corticospinal tracts
D. Hypoxia from anemia leads to ischemic damage to the spinal cord and peripheral nerves
Answer: A. Deficiency of vitamin B12 leads to accumulation of methylmalonic acid, which
impairs myelin synthesis in the nervous system
5. Which of the following clinical findings is MOST suggestive of left-sided heart failure with
preserved ejection fraction (HFpEF) rather than right-sided heart failure?
A. Jugular venous distension and peripheral edema
B. Pulmonary crackles and paroxysmal nocturnal dyspnea
C. Hepatomegaly and ascites
D. Elevated B-type natriuretic peptide (BNP) with normal ejection fraction on echocardiogram
Answer: B. Pulmonary crackles and paroxysmal nocturnal dyspnea
6. A 28-year-old female with a history of long-standing type 1 diabetes mellitus presents with
nausea, vomiting, and abdominal pain. Arterial blood gas shows pH 7.20, pCO2 30 mmHg,
bicarbonate 12 mEq/L, and glucose 450 mg/dL. Serum ketones are positive. Which
compensatory mechanism is MOST active in this patient's acid-base disturbance?
A. Renal retention of bicarbonate and increased excretion of hydrogen ions
B. Hyperventilation with increased respiratory rate to blow off carbon dioxide
C. Hypoventilation to retain carbon dioxide and increase bicarbonate
D. Increased hepatic gluconeogenesis to produce more ketone bodies
Answer: B. Hyperventilation with increased respiratory rate to blow off carbon dioxide
7. A 60-year-old male with cirrhosis due to non-alcoholic steatohepatitis presents with
confusion, asterixis, and a serum ammonia level of 80 µmol/L (normal 15-45). Which of the
following is the BEST initial pharmacologic intervention for treating this patient's hepatic
encephalopathy?
A. Oral lactulose to acidify the colon and trap ammonia in the form of ammonium ions
B. Intravenous flumazenil to reverse benzodiazepine-induced encephalopathy
C. Oral neomycin to reduce gut bacteria that produce ammonia
D. Intravenous branched-chain amino acids to correct amino acid imbalance
Answer: A. Oral lactulose to acidify the colon and trap ammonia in the form of ammonium ions
8. A 45-year-old woman on chronic oral corticosteroid therapy for asthma presents with sudden
severe back pain and is found to have a wedge compression fracture at T12 on radiography.
Which mechanism of bone loss is PRIMARILY responsible for her increased fracture risk?
A. Increased apoptosis of osteoblasts and decreased bone formation due to corticosteroid-induced
suppression of osteoblast activity
B. Increased osteoclast activity due to secondary hyperparathyroidism from corticosteroid-induced
hypercalciuria
C. Decreased intestinal calcium absorption and increased renal calcium excretion leading to calcium
deficiency and increased PTH
, D. Alterations in sex hormone production leading to increased bone resorption
Answer: A. Increased apoptosis of osteoblasts and decreased bone formation due to
corticosteroid-induced suppression of osteoblast activity
9. A 75-year-old male with metastatic prostate cancer is treated with a long-acting GnRH
agonist (leuprolide). Three weeks after the first injection, he presents with severe bone pain
and an elevated serum calcium of 11.5 mg/dL. Which pathophysiologic mechanism is the MOST
likely cause of his hypercalcemia?
A. Tumor lysis syndrome with rapid release of intracellular phosphate and calcium
B. Ectopic secretion of parathyroid hormone-related protein (PTHrP) by the prostate cancer cells
C. Osteoblastic metastases leading to increased bone formation and calcium deposition
D. Leuprolide-induced transient flare in testosterone production, causing increased osteoclast activity and
bone resorption
Answer: D. Leuprolide-induced transient flare in testosterone production, causing increased
osteoclast activity and bone resorption
10. A 32-year-old female with a history of asthma is admitted to the ICU with an acute
exacerbation. She is anxious, tachypneic, and using accessory muscles. SpO2 is 88% on 100%
non-rebreather mask. Arterial blood gas shows pH 7.46, pCO2 32 mmHg, HCO3 24 mEq/L.
Which of the following is the BEST next step in management?
A. Intubate the patient immediately with mechanical ventilation to relieve respiratory failure
B. Administer continuous nebulized albuterol and intravenous corticosteroids
C. Give intravenous magnesium sulfate as a bronchodilator
D. Perform a chest radiograph to rule out pneumothorax before treatment
Answer: B. Administer continuous nebulized albuterol and intravenous corticosteroids
11. A 68-year-old male with a history of heart failure is prescribed furosemide. Which adverse
effect is MOST directly caused by the mechanism of action of this drug?
A. Hypokalemia and metabolic alkalosis due to increased potassium and hydrogen ion secretion in the distal
tubule
B. Hypernatremia due to increased water reabsorption in the collecting duct
C. Hypocalcemia due to increased renal calcium excretion in the thick ascending limb
D. Hyperuricemia due to decreased uric acid secretion in the proximal tubule
Answer: A. Hypokalemia and metabolic alkalosis due to increased potassium and hydrogen ion
secretion in the distal tubule
12. A 55-year-old female with chronic hypertension presents with a blood pressure of 170/100
mmHg and is started on lisinopril. One week later, she develops a dry cough. Which
mechanism is MOST responsible for this adverse effect?
A. Inhibition of angiotensin-converting enzyme leading to increased levels of bradykinin in the lungs
B. Decreased aldosterone secretion leading to sodium and water loss
C. Increased sensitivity of cough reflex due to reduced angiotensin II
D. Direct toxic effect of the drug on the pulmonary epithelium causing inflammation
Answer: A. Inhibition of angiotensin-converting enzyme leading to increased levels of
bradykinin in the lungs
13. A 3-year-old child presents with acute onset of fever, sore throat, and a grayish-white
membrane covering the tonsils and pharynx. The membrane is firmly adherent and bleeding is
450 REAL EXAM QUESTIONS AND CORRECT ANSWERS
WITH RATIONALES/ WGU D115 ADVANCED
PATHOPHYSIOLOGY OA PREP(NEW!)
1. A 62-year-old male with a history of chronic obstructive pulmonary disease (COPD) presents
with increased dyspnea, productive cough, and fever. Chest radiograph reveals a new right
lower lobe infiltrate. Sputum Gram stain shows gram-positive diplococci, and blood cultures
grow Streptococcus pneumoniae. Despite appropriate antibiotic therapy, the patient develops
acute respiratory distress syndrome (ARDS). Which pathophysiologic mechanism is the
PRIMARY contributor to the development of ARDS in this patient?
A. Excessive influx of neutrophils into the alveolar space with release of reactive oxygen species and
proteases
B. Direct bacterial invasion of the alveolar epithelium leading to necrotizing pneumonia and cavitation
C. Impaired mucociliary clearance causing mucus plugging and atelectasis with subsequent shunt physiology
D. Type II pneumocyte hyperplasia resulting in increased surfactant production and alveolar stability
Answer: A. Excessive influx of neutrophils into the alveolar space with release of reactive
oxygen species and proteases
2. A 45-year-old woman with systemic lupus erythematosus (SLE) presents with fatigue, joint
pain, and a malar rash. Laboratory studies show anemia, leukopenia, and a positive
anti-double-stranded DNA (anti-dsDNA) antibody test. Which type of hypersensitivity reaction is
MOST consistent with the pathogenesis of her lupus nephritis?
A. Type II hypersensitivity mediated by antibodies against glomerular basement membrane
B. Type III hypersensitivity with immune complex deposition in the glomeruli
C. Type IV hypersensitivity mediated by T-helper 1 cells and macrophage activation
D. Type I hypersensitivity with mast cell degranulation and histamine release
Answer: B. Type III hypersensitivity with immune complex deposition in the glomeruli
3. A 70-year-old male with chronic kidney disease stage 4 has a serum creatinine of 3.5 mg/dL
and a calcium of 8.2 mg/dL (normal 8.5-10.5), phosphate of 6.0 mg/dL (normal 2.5-4.5), and an
intact parathyroid hormone (PTH) level of 250 pg/mL (normal 10-65). Which pathophysiologic
change is the MOST likely cause of the elevated PTH level in this patient?
A. Decreased renal activation of vitamin D leading to reduced intestinal calcium absorption and hypocalcemia,
stimulating PTH secretion
B. Increased renal phosphate excretion causing hypophosphatemia, which directly stimulates parathyroid
chief cells to release PTH
C. Direct toxic effect of uremic toxins on the parathyroid glands causing autonomous (tertiary)
hyperparathyroidism
D. Increased calcium-sensing receptor (CaSR) expression on parathyroid cells producing a lower set point for
PTH suppression
Answer: A. Decreased renal activation of vitamin D leading to reduced intestinal calcium
absorption and hypocalcemia, stimulating PTH secretion
4. A 55-year-old male with a history of alcohol use disorder is found to have a macrocytic
anemia. His peripheral smear shows hypersegmented neutrophils and oval macrocytes. Serum
,vitamin B12 is 150 pg/mL (normal 200-900) and folate is normal. Which pathophysiologic
mechanism is MOST responsible for the neurologic symptoms that may accompany his
anemia?
A. Deficiency of vitamin B12 leads to accumulation of methylmalonic acid, which impairs myelin synthesis in
the nervous system
B. Folate deficiency causes impaired DNA synthesis in neuronal cells leading to axonal degeneration
C. Chronic alcohol toxicity directly damages the dorsal columns and corticospinal tracts
D. Hypoxia from anemia leads to ischemic damage to the spinal cord and peripheral nerves
Answer: A. Deficiency of vitamin B12 leads to accumulation of methylmalonic acid, which
impairs myelin synthesis in the nervous system
5. Which of the following clinical findings is MOST suggestive of left-sided heart failure with
preserved ejection fraction (HFpEF) rather than right-sided heart failure?
A. Jugular venous distension and peripheral edema
B. Pulmonary crackles and paroxysmal nocturnal dyspnea
C. Hepatomegaly and ascites
D. Elevated B-type natriuretic peptide (BNP) with normal ejection fraction on echocardiogram
Answer: B. Pulmonary crackles and paroxysmal nocturnal dyspnea
6. A 28-year-old female with a history of long-standing type 1 diabetes mellitus presents with
nausea, vomiting, and abdominal pain. Arterial blood gas shows pH 7.20, pCO2 30 mmHg,
bicarbonate 12 mEq/L, and glucose 450 mg/dL. Serum ketones are positive. Which
compensatory mechanism is MOST active in this patient's acid-base disturbance?
A. Renal retention of bicarbonate and increased excretion of hydrogen ions
B. Hyperventilation with increased respiratory rate to blow off carbon dioxide
C. Hypoventilation to retain carbon dioxide and increase bicarbonate
D. Increased hepatic gluconeogenesis to produce more ketone bodies
Answer: B. Hyperventilation with increased respiratory rate to blow off carbon dioxide
7. A 60-year-old male with cirrhosis due to non-alcoholic steatohepatitis presents with
confusion, asterixis, and a serum ammonia level of 80 µmol/L (normal 15-45). Which of the
following is the BEST initial pharmacologic intervention for treating this patient's hepatic
encephalopathy?
A. Oral lactulose to acidify the colon and trap ammonia in the form of ammonium ions
B. Intravenous flumazenil to reverse benzodiazepine-induced encephalopathy
C. Oral neomycin to reduce gut bacteria that produce ammonia
D. Intravenous branched-chain amino acids to correct amino acid imbalance
Answer: A. Oral lactulose to acidify the colon and trap ammonia in the form of ammonium ions
8. A 45-year-old woman on chronic oral corticosteroid therapy for asthma presents with sudden
severe back pain and is found to have a wedge compression fracture at T12 on radiography.
Which mechanism of bone loss is PRIMARILY responsible for her increased fracture risk?
A. Increased apoptosis of osteoblasts and decreased bone formation due to corticosteroid-induced
suppression of osteoblast activity
B. Increased osteoclast activity due to secondary hyperparathyroidism from corticosteroid-induced
hypercalciuria
C. Decreased intestinal calcium absorption and increased renal calcium excretion leading to calcium
deficiency and increased PTH
, D. Alterations in sex hormone production leading to increased bone resorption
Answer: A. Increased apoptosis of osteoblasts and decreased bone formation due to
corticosteroid-induced suppression of osteoblast activity
9. A 75-year-old male with metastatic prostate cancer is treated with a long-acting GnRH
agonist (leuprolide). Three weeks after the first injection, he presents with severe bone pain
and an elevated serum calcium of 11.5 mg/dL. Which pathophysiologic mechanism is the MOST
likely cause of his hypercalcemia?
A. Tumor lysis syndrome with rapid release of intracellular phosphate and calcium
B. Ectopic secretion of parathyroid hormone-related protein (PTHrP) by the prostate cancer cells
C. Osteoblastic metastases leading to increased bone formation and calcium deposition
D. Leuprolide-induced transient flare in testosterone production, causing increased osteoclast activity and
bone resorption
Answer: D. Leuprolide-induced transient flare in testosterone production, causing increased
osteoclast activity and bone resorption
10. A 32-year-old female with a history of asthma is admitted to the ICU with an acute
exacerbation. She is anxious, tachypneic, and using accessory muscles. SpO2 is 88% on 100%
non-rebreather mask. Arterial blood gas shows pH 7.46, pCO2 32 mmHg, HCO3 24 mEq/L.
Which of the following is the BEST next step in management?
A. Intubate the patient immediately with mechanical ventilation to relieve respiratory failure
B. Administer continuous nebulized albuterol and intravenous corticosteroids
C. Give intravenous magnesium sulfate as a bronchodilator
D. Perform a chest radiograph to rule out pneumothorax before treatment
Answer: B. Administer continuous nebulized albuterol and intravenous corticosteroids
11. A 68-year-old male with a history of heart failure is prescribed furosemide. Which adverse
effect is MOST directly caused by the mechanism of action of this drug?
A. Hypokalemia and metabolic alkalosis due to increased potassium and hydrogen ion secretion in the distal
tubule
B. Hypernatremia due to increased water reabsorption in the collecting duct
C. Hypocalcemia due to increased renal calcium excretion in the thick ascending limb
D. Hyperuricemia due to decreased uric acid secretion in the proximal tubule
Answer: A. Hypokalemia and metabolic alkalosis due to increased potassium and hydrogen ion
secretion in the distal tubule
12. A 55-year-old female with chronic hypertension presents with a blood pressure of 170/100
mmHg and is started on lisinopril. One week later, she develops a dry cough. Which
mechanism is MOST responsible for this adverse effect?
A. Inhibition of angiotensin-converting enzyme leading to increased levels of bradykinin in the lungs
B. Decreased aldosterone secretion leading to sodium and water loss
C. Increased sensitivity of cough reflex due to reduced angiotensin II
D. Direct toxic effect of the drug on the pulmonary epithelium causing inflammation
Answer: A. Inhibition of angiotensin-converting enzyme leading to increased levels of
bradykinin in the lungs
13. A 3-year-old child presents with acute onset of fever, sore throat, and a grayish-white
membrane covering the tonsils and pharynx. The membrane is firmly adherent and bleeding is
