APEA PATHOPHYSIOLOGY ACTUAL EXAM
REVIEW 2026 – LATEST EDITION 180 Questions
with Correct Answers & Detailed Rationales
Guarantee A+ Grade
Question 1
A 45-year-old male presents with fatigue, weight loss, and night sweats. Laboratory findings
show normocytic, normochromic anemia and an elevated erythrocyte sedimentation rate (ESR).
A chest X-ray reveals a mediastinal mass. Which pathophysiologic process is most likely
responsible for these findings?
A) Hodgkin lymphoma involving Reed-Sternberg cells
B) Small cell lung cancer with paraneoplastic syndrome
C) Tuberculosis with caseating granulomas
D) Sarcoidosis with non-caseating granulomas
Correct Answer: A
Rationale: Hodgkin lymphoma classically presents with B symptoms (fever, night sweats, weight
loss), mediastinal mass, and normocytic anemia. Reed-Sternberg cells are the malignant cells.
Question 2
A patient with a history of hypertension and diabetes presents with sudden onset of severe
"tearing" chest pain radiating to the back. Blood pressure is 160/90 mmHg in the right arm and
110/70 mmHg in the left arm. What is the most likely diagnosis?
A) Myocardial infarction
B) Pulmonary embolism
C) Aortic dissection
D) Pericarditis
Correct Answer: C
Rationale: Aortic dissection presents with sudden, severe tearing chest pain and pulse or blood
pressure differential between arms due to intimal tear and propagation of the dissection flap.
Question 3
,A 60-year-old male with a 40-pack-year smoking history presents with hemoptysis, weight loss,
and a persistent cough. Chest X-ray shows a right hilar mass with mediastinal
lymphadenopathy. Biopsy shows small, round blue cells. What is the most likely diagnosis?
A) Squamous cell carcinoma
B) Adenocarcinoma
C) Small cell lung cancer
D) Large cell carcinoma
Correct Answer: C
Rationale: Small cell lung cancer presents with central (hilar) mass, early metastasis, and
paraneoplastic syndromes. Histology shows small, round blue cells with scant cytoplasm.
Question 4
Which of the following is the most common cause of community-acquired pneumonia in adults?
A) Mycoplasma pneumoniae
B) Streptococcus pneumoniae
C) Haemophilus influenzae
D) Legionella pneumophila
Correct Answer: B
Rationale: Streptococcus pneumoniae (pneumococcus) is the most common cause of
community-acquired pneumonia in adults, accounting for approximately 30-50% of cases.
Question 5
A 55-year-old female with rheumatoid arthritis presents with shortness of breath and dry cough.
High-resolution CT shows bilateral reticular opacities and honeycombing in the lower lobes.
What is the most likely diagnosis?
A) Idiopathic pulmonary fibrosis
B) Hypersensitivity pneumonitis
C) Rheumatoid arthritis-associated interstitial lung disease
D) Sarcoidosis
Correct Answer: C
Rationale: Rheumatoid arthritis is associated with interstitial lung disease (usual interstitial
pneumonia pattern), presenting with progressive dyspnea, dry cough, and basilar predominant
reticular opacities and honeycombing.
Question 6
,A 32-year-old male presents with acute shortness of breath and sharp chest pain after a long
flight. He is tachycardic and hypoxic. D-dimer is elevated. What is the most specific diagnostic
test?
A) Chest X-ray
B) CT pulmonary angiography (CTPA)
C) Ventilation-perfusion (V/Q) scan
D) Echocardiogram
Correct Answer: B
Rationale: CTPA is the gold standard for diagnosing pulmonary embolism, with high sensitivity
and specificity for detecting emboli in the pulmonary arteries.
Question 7
A patient with chronic obstructive pulmonary disease (COPD) has an arterial blood gas showing
pH 7.32, PaCO2 65 mmHg, PaO2 58 mmHg, HCO3 30 mEq/L. What is the interpretation?
A) Acute respiratory acidosis
B) Chronic respiratory acidosis with acute exacerbation
C) Metabolic alkalosis
D) Compensated metabolic acidosis
Correct Answer: B
Rationale: Low pH (acidemia), elevated PaCO2 (respiratory acidosis), and elevated HCO3
(chronic compensation) indicate chronic respiratory acidosis with acute exacerbation
(acute-on-chronic).
Question 8
A 28-year-old female presents with acute-onset, severe, unilateral periorbital headache
associated with ipsilateral conjunctival injection, rhinorrhea, and ptosis. The headache lasts 45
minutes and occurs at the same time each night. What is the most likely diagnosis?
A) Migraine
B) Tension headache
C) Cluster headache
D) Subarachnoid hemorrhage
Correct Answer: C
Rationale: Cluster headaches are unilateral, periorbital, associated with autonomic symptoms
(conjunctival injection, rhinorrhea, ptosis), short duration (15-180 minutes), and occur with
circadian periodicity.
, Question 9
A 72-year-old male presents with gradual-onset memory loss, difficulty with daily activities, and
no focal neurologic deficits. Mini-Mental State Exam is 20/30. What is the most likely diagnosis?
A) Vascular dementia
B) Alzheimer's disease
C) Lewy body dementia
D) Frontotemporal dementia
Correct Answer: B
Rationale: Alzheimer's disease is the most common cause of dementia, presenting with gradual
onset, progressive memory loss (especially recent memory), and absence of focal deficits.
Question 10
A patient with a history of atrial fibrillation is started on warfarin. The INR is 4.8. The patient has
no signs of bleeding. What is the most appropriate action?
A) Administer vitamin K 2.5 mg orally
B) Hold the next dose of warfarin and monitor
C) Administer fresh frozen plasma
D) Increase the warfarin dose
Correct Answer: B
Rationale: For an asymptomatic patient with INR 4.5-10, holding warfarin is appropriate. Vitamin
K is reserved for INR >10 or active bleeding.
Question 11
A 45-year-old female presents with episodes of palpitations, anxiety, diaphoresis, and
hypertension. During one episode, her blood pressure is 190/110 mmHg. Between episodes,
she is normotensive. What is the most likely diagnosis?
A) Essential hypertension
B) Pheochromocytoma
C) Hyperthyroidism
D) Panic disorder
Correct Answer: B
Rationale: Pheochromocytoma (catecholamine-secreting tumor) presents with paroxysmal
hypertension, palpitations, diaphoresis, and headache (the "spells").
REVIEW 2026 – LATEST EDITION 180 Questions
with Correct Answers & Detailed Rationales
Guarantee A+ Grade
Question 1
A 45-year-old male presents with fatigue, weight loss, and night sweats. Laboratory findings
show normocytic, normochromic anemia and an elevated erythrocyte sedimentation rate (ESR).
A chest X-ray reveals a mediastinal mass. Which pathophysiologic process is most likely
responsible for these findings?
A) Hodgkin lymphoma involving Reed-Sternberg cells
B) Small cell lung cancer with paraneoplastic syndrome
C) Tuberculosis with caseating granulomas
D) Sarcoidosis with non-caseating granulomas
Correct Answer: A
Rationale: Hodgkin lymphoma classically presents with B symptoms (fever, night sweats, weight
loss), mediastinal mass, and normocytic anemia. Reed-Sternberg cells are the malignant cells.
Question 2
A patient with a history of hypertension and diabetes presents with sudden onset of severe
"tearing" chest pain radiating to the back. Blood pressure is 160/90 mmHg in the right arm and
110/70 mmHg in the left arm. What is the most likely diagnosis?
A) Myocardial infarction
B) Pulmonary embolism
C) Aortic dissection
D) Pericarditis
Correct Answer: C
Rationale: Aortic dissection presents with sudden, severe tearing chest pain and pulse or blood
pressure differential between arms due to intimal tear and propagation of the dissection flap.
Question 3
,A 60-year-old male with a 40-pack-year smoking history presents with hemoptysis, weight loss,
and a persistent cough. Chest X-ray shows a right hilar mass with mediastinal
lymphadenopathy. Biopsy shows small, round blue cells. What is the most likely diagnosis?
A) Squamous cell carcinoma
B) Adenocarcinoma
C) Small cell lung cancer
D) Large cell carcinoma
Correct Answer: C
Rationale: Small cell lung cancer presents with central (hilar) mass, early metastasis, and
paraneoplastic syndromes. Histology shows small, round blue cells with scant cytoplasm.
Question 4
Which of the following is the most common cause of community-acquired pneumonia in adults?
A) Mycoplasma pneumoniae
B) Streptococcus pneumoniae
C) Haemophilus influenzae
D) Legionella pneumophila
Correct Answer: B
Rationale: Streptococcus pneumoniae (pneumococcus) is the most common cause of
community-acquired pneumonia in adults, accounting for approximately 30-50% of cases.
Question 5
A 55-year-old female with rheumatoid arthritis presents with shortness of breath and dry cough.
High-resolution CT shows bilateral reticular opacities and honeycombing in the lower lobes.
What is the most likely diagnosis?
A) Idiopathic pulmonary fibrosis
B) Hypersensitivity pneumonitis
C) Rheumatoid arthritis-associated interstitial lung disease
D) Sarcoidosis
Correct Answer: C
Rationale: Rheumatoid arthritis is associated with interstitial lung disease (usual interstitial
pneumonia pattern), presenting with progressive dyspnea, dry cough, and basilar predominant
reticular opacities and honeycombing.
Question 6
,A 32-year-old male presents with acute shortness of breath and sharp chest pain after a long
flight. He is tachycardic and hypoxic. D-dimer is elevated. What is the most specific diagnostic
test?
A) Chest X-ray
B) CT pulmonary angiography (CTPA)
C) Ventilation-perfusion (V/Q) scan
D) Echocardiogram
Correct Answer: B
Rationale: CTPA is the gold standard for diagnosing pulmonary embolism, with high sensitivity
and specificity for detecting emboli in the pulmonary arteries.
Question 7
A patient with chronic obstructive pulmonary disease (COPD) has an arterial blood gas showing
pH 7.32, PaCO2 65 mmHg, PaO2 58 mmHg, HCO3 30 mEq/L. What is the interpretation?
A) Acute respiratory acidosis
B) Chronic respiratory acidosis with acute exacerbation
C) Metabolic alkalosis
D) Compensated metabolic acidosis
Correct Answer: B
Rationale: Low pH (acidemia), elevated PaCO2 (respiratory acidosis), and elevated HCO3
(chronic compensation) indicate chronic respiratory acidosis with acute exacerbation
(acute-on-chronic).
Question 8
A 28-year-old female presents with acute-onset, severe, unilateral periorbital headache
associated with ipsilateral conjunctival injection, rhinorrhea, and ptosis. The headache lasts 45
minutes and occurs at the same time each night. What is the most likely diagnosis?
A) Migraine
B) Tension headache
C) Cluster headache
D) Subarachnoid hemorrhage
Correct Answer: C
Rationale: Cluster headaches are unilateral, periorbital, associated with autonomic symptoms
(conjunctival injection, rhinorrhea, ptosis), short duration (15-180 minutes), and occur with
circadian periodicity.
, Question 9
A 72-year-old male presents with gradual-onset memory loss, difficulty with daily activities, and
no focal neurologic deficits. Mini-Mental State Exam is 20/30. What is the most likely diagnosis?
A) Vascular dementia
B) Alzheimer's disease
C) Lewy body dementia
D) Frontotemporal dementia
Correct Answer: B
Rationale: Alzheimer's disease is the most common cause of dementia, presenting with gradual
onset, progressive memory loss (especially recent memory), and absence of focal deficits.
Question 10
A patient with a history of atrial fibrillation is started on warfarin. The INR is 4.8. The patient has
no signs of bleeding. What is the most appropriate action?
A) Administer vitamin K 2.5 mg orally
B) Hold the next dose of warfarin and monitor
C) Administer fresh frozen plasma
D) Increase the warfarin dose
Correct Answer: B
Rationale: For an asymptomatic patient with INR 4.5-10, holding warfarin is appropriate. Vitamin
K is reserved for INR >10 or active bleeding.
Question 11
A 45-year-old female presents with episodes of palpitations, anxiety, diaphoresis, and
hypertension. During one episode, her blood pressure is 190/110 mmHg. Between episodes,
she is normotensive. What is the most likely diagnosis?
A) Essential hypertension
B) Pheochromocytoma
C) Hyperthyroidism
D) Panic disorder
Correct Answer: B
Rationale: Pheochromocytoma (catecholamine-secreting tumor) presents with paroxysmal
hypertension, palpitations, diaphoresis, and headache (the "spells").
