Community-Acquired Pneumonia: 10 Single-Best-Answer Questions for Year 4 Medical Students
Question 1
A 68-year-old man presents to the emergency department with a 3-day history of productive cough, fever, and pleuritic chest pain. His vital signs are: temperature 38.9°C, heart rate 102 bpm, blood pressure 128/76 mmHg, respiratory rate 24 breaths/min, oxygen saturation 91% on room air. He is alert and oriented. His CURB-65 score is 2. Which of the following is the most appropriate initial management decision?
A. Discharge home with oral amoxicillin
B. Admit to hospital ward for intravenous antibiotics
C. Admit directly to intensive care unit
D. Discharge home with oral doxycycline alone
E. Observe in emergency department for 6 hours then reassess
Question 2
A 45-year-old woman with no significant past medical history presents with fever, cough, and dyspnea. Chest radiograph confirms right lower lobe consolidation. A nasopharyngeal swab PCR returns positive for influenza A. Her vital signs are stable with oxygen saturation 94% on room air. What is the most appropriate antibiotic management?
A. Withhold antibiotics and treat with oseltamivir only
B. Start amoxicillin-clavulanate and macrolide empirically
C. Start oseltamivir and observe for 48 hours before considering antibiotics
D. Start doxycycline monotherapy
E. No treatment needed as this is viral pneumonia
Question 3
A 72-year-old man is admitted with community-acquired pneumonia. He has been treated with intravenous co-amoxiclav and clarithromycin for 48 hours. His temperature has normalized, respiratory rate is 18 breaths/min, and oxygen saturation is 96% on room air. He is tolerating oral intake. What is the most appropriate next step in antibiotic management?
A. Continue intravenous antibiotics for a total of 7 days
B. Switch to oral antibiotics and plan for 5-day total duration
C. Continue intravenous antibiotics for 5 days then switch to oral for 7 more days
D. Stop antibiotics as he has clinically improved
E. Continue intravenous antibiotics for 10 days total
Question 4
A 55-year-old man presents with severe community-acquired pneumonia requiring ICU admission. He has bilateral infiltrates on chest radiograph, respiratory rate 32 breaths/min, and requires high-flow oxygen. His blood pressure is 118/72 mmHg on admission. Which of the following statements regarding corticosteroid therapy is most accurate?
A. All patients with severe CAP should receive corticosteroids
B. Corticosteroids should be given only if the patient develops septic shock
C. Corticosteroids reduce mortality in all ICU patients with CAP
D. A 7-day course of prednisolone 50mg daily should be started immediately
E. Corticosteroids are contraindicated in severe CAP
Question 5
A 62-year-old woman presents to the emergency department with suspected pneumonia. She has cough, fever, and crackles on auscultation of the right lung base. Chest radiograph is not immediately available. Point-of-care lung ultrasound is performed. Which ultrasound finding would most strongly support the diagnosis of pneumonia?
A. A-lines with normal lung sliding
B. Subpleural consolidation with air bronchograms
C. Bilateral B-lines in a diffuse pattern
D. Pleural effusion alone without parenchymal changes
E. Absence of lung sliding with normal A-lines
Question 6
A 58-year-old man with COPD presents with community-acquired pneumonia. He has a history of hospitalization for pneumonia requiring mechanical ventilation 8 months ago. His current vital signs show temperature 38.5°C, heart rate 98 bpm, blood pressure 132/78 mmHg, respiratory rate 22 breaths/min, oxygen saturation 92% on 2L nasal cannula. What is the most appropriate empiric antibiotic regimen?
A. Amoxicillin alone
B. Doxycycline alone
C. Beta-lactam plus macrolide
D. Anti-pseudomonal beta-lactam plus fluoroquinolone
E. Fluoroquinolone monotherapy
Question 7
A 48-year-old previously healthy woman is admitted with community-acquired pneumonia. She is started on appropriate antibiotics. On day 3, she remains febrile with persistent tachycardia. Her C-reactive protein (CRP) on admission was 285 mg/L. A repeat CRP on day 4 is 260 mg/L. What does this CRP trend most strongly suggest?
A. Normal response to therapy; continue current management
B. Increased risk of complications and treatment failure
C. Antibiotic resistance; change to broader spectrum immediately
D. Viral etiology; stop antibiotics
E. Laboratory error; repeat the test
Question 8
A 70-year-old man is diagnosed with right lower lobe pneumonia and treated successfully as an outpatient. He completes a 5-day course of antibiotics and his symptoms resolve completely. He has a 40 pack-year smoking history. When should follow-up chest imaging be performed?
A. Immediately after completing antibiotics
B. 2 weeks after diagnosis
C. 4-6 weeks after diagnosis
D. 3 months after diagnosis
E. No follow-up imaging needed as symptoms resolved
Question 9
A 52-year-old woman presents with fever, productive cough, and left-sided pleuritic chest pain. On examination, she has decreased breath sounds and dullness to percussion at the left base. Chest radiograph shows left lower lobe consolidation with a moderate pleural effusion. Diagnostic thoracentesis yields cloudy fluid with pH 7.1, glucose 1.8 mmol/L, and LDH 850 U/L. What is the most appropriate management?
A. Continue antibiotics alone and repeat imaging in 48 hours
B. Chest tube drainage plus antibiotics
C. Increase antibiotic dose and add corticosteroids
D. Therapeutic thoracentesis and continue antibiotics
E. Urgent thoracic surgery referral for decortication
Question 10
A 65-year-old man with diabetes and hypertension presents with community-acquired pneumonia. His CURB-65 score is 1 (age >65). His vital signs are: temperature 38.2°C, heart rate 88 bpm, blood pressure 138/82 mmHg, respiratory rate 20 breaths/min, oxygen saturation 95% on room air. His serum lactate is 3.2 mmol/L. What is the most appropriate disposition?
A. Discharge home with oral antibiotics
B. Admit to hospital ward
C. Admit to high-dependency unit
D. Observe in emergency department for 4 hours then discharge
E. Admit to ICU
ANSWER KEY AND EXPLANATIONS
Question 1: Answer B
Correct Answer: B. Admit to hospital ward for intravenous antibiotics
Learning Objective: Apply severity assessment tools and clinical judgment to determine appropriate site of care for patients with community-acquired pneumonia.
Cognitive Level: Application/Analysis (Bloom's Level 3)
Explanation:
This patient requires hospital admission based on his CURB-65 score of 2 and clinical presentation 1. The 2019 ATS/IDSA guidelines emphasize using validated severity scores alongside clinical judgment for site-of-care decisions 1. A CURB-65 score of 2 indicates moderate severity with increased mortality risk, warranting hospital admission 2.
Why B is correct: CURB-65 score ≥2 is an indication for hospital admission. This patient has hypoxemia (SpO2 91%), tachypnea (RR 24), and systemic signs of infection, all supporting inpatient management with parenteral antibiotics initially 1.
Why A is incorrect: Discharge would be inappropriate with CURB-65 ≥2. Outpatient management is typically reserved for CURB-65 0-1 with no other concerning features 3.
Why C is incorrect: Direct ICU admission is not indicated. He does not meet criteria for severe CAP (no septic shock, no need for mechanical ventilation, no evidence of multi-organ failure) 1.
Why D is incorrect: Same reasoning as A—discharge is inappropriate given severity score and hypoxemia.
Why E is incorrect: Observation alone delays definitive treatment. The patient clearly meets admission criteria and should be started on appropriate antibiotics promptly 3.
Key Clinical Pitfall: CURB-65 alone may underestimate severity. Always incorporate clinical judgment, oxygen requirements, and lactate levels when available 3, 4.
Question 2: Answer B
Correct Answer: B. Start amoxicillin-clavulanate and macrolide empirically
Learning Objective: Understand that detection of respiratory viruses does not exclude bacterial co-infection and should not delay empiric antibiotic therapy in patients with radiographic pneumonia.
Cognitive Level: Application/Analysis (Bloom's Level 3)
Explanation:
Patients with radiographic pneumonia should receive empiric antibacterial therapy even when a respiratory virus is detected 5. The 2025 ATS guideline update specifically addresses this, recommending against withholding antibiotics based solely on positive viral testing 5.
Why B is correct: This patient has radiographic consolidation confirming pneumonia. Bacterial co-infection or secondary bacterial pneumonia is common with influenza, and empiric antibiotics should not be withheld 5. The combination of beta-lactam plus macrolide is appropriate for hospitalized CAP patients without risk factors for resistant organisms 1.
Why A is incorrect: Withholding antibiotics puts the patient at risk. Viral detection in upper airway samples does not exclude bacterial pneumonia, and delays in antibiotic therapy increase mortality 5.
Why C is incorrect: Observing for 48 hours before starting antibiotics is dangerous. Early antibiotic administration improves outcomes in bacterial pneumonia 3.
Why D is incorrect: While doxycycline can be used for outpatient CAP, this patient requires broader coverage given radiographic pneumonia, and monotherapy may be inadequate 1.
Why E is incorrect: Radiographic consolidation with clinical pneumonia requires antibacterial treatment regardless of viral detection 5.
Key Clinical Pitfall: Do not be falsely reassured by positive viral tests. Bacterial-viral co-infection is common, and antibiotic therapy should be initiated based on clinical and radiographic findings 6, 5.
Question 3: Answer B
Correct Answer: B. Switch to oral antibiotics and plan for 5-day total duration
Learning Objective: Apply evidence-based principles for antibiotic duration and route of administration in community-acquired pneumonia.
Cognitive Level: Application/Synthesis (Bloom's Level 3-4)
Explanation:
Shorter antibiotic courses (5 days) are as effective as longer courses for uncomplicated CAP when patients demonstrate clinical stability 5. The 2025 ATS guideline recommends 5-day courses for most patients with CAP 5.
Why B is correct: This patient meets criteria for clinical stability (afebrile, normal respiratory rate, adequate oxygenation, tolerating oral intake). He can be switched to oral antibiotics and complete a 5-day total course 5. Shorter courses reduce antibiotic exposure without compromising outcomes 3.
Why A is incorrect: Seven days is unnecessarily long for uncomplicated CAP. Extended courses increase adverse effects and antibiotic resistance without improving outcomes 5.
Why C is incorrect: A total of 12 days is excessive for uncomplicated CAP. This duration would only be considered for complicated pneumonia (empyema, lung abscess, bacteremia with slow response) 3.
Why D is incorrect: Stopping at 48 hours is premature. Even with clinical improvement, a minimum 5-day course is recommended to ensure adequate treatment 5.
Why E is incorrect: Ten days of intravenous therapy is unnecessarily prolonged and increases complications from IV access, cost, and length of stay 3.
Key Clinical Pitfall: Avoid reflexively prescribing 7-10 day courses. Clinical stability by day 3-4 allows for shorter therapy, reducing antibiotic-related harm 5, 3.
Question 4: Answer B
Correct Answer: B. Corticosteroids should be given only if the patient develops septic shock
Learning Objective: Understand the evolving and limited role of corticosteroids in severe community-acquired pneumonia based on recent evidence.
Cognitive Level: Analysis/Evaluation (Bloom's Level 4-5)
Explanation:
The role of corticosteroids in severe CAP has become more restricted following recent evidence 6, 5. The 2025 ATS guideline suggests corticosteroids only for patients with refractory septic shock, not routinely for all severe CAP 5.
Why B is correct: The REMAP-CAP study and subsequent guideline updates indicate corticosteroids should be reserved for patients with septic shock requiring vasopressors 6, 5. This patient has normal blood pressure and does not meet criteria for shock.
Why A is incorrect: Routine corticosteroid use in all severe CAP is not supported by current evidence and may cause harm 6, 5.
Why C is incorrect: Corticosteroids do not reduce mortality in all ICU patients with CAP. Recent evidence suggests benefit is limited to those with septic shock 6.
Why D is incorrect: Starting corticosteroids immediately in a hemodynamically stable patient is not indicated and contradicts current guidelines 5.
Why E is incorrect: Corticosteroids are not contraindicated but should be used selectively, primarily in septic shock 5.
Key Clinical Pitfall: The evidence for corticosteroids has evolved significantly. Avoid routine use in severe CAP; reserve for refractory septic shock 6, 5.
Question 5: Answer B
Correct Answer: B. Subpleural consolidation with air bronchograms
Learning Objective: Recognize the ultrasound findings diagnostic of pneumonia and understand the role of point-of-care lung ultrasound in CAP diagnosis.
Cognitive Level: Knowledge/Application (Bloom's Level 2-3)
Explanation:
Lung ultrasound showing consolidation with air bronchograms is highly specific for pneumonia 5. The 2025 ATS guideline endorses lung ultrasound as an alternative to chest radiography for diagnosing CAP 5.
Why B is correct: Subpleural consolidation with dynamic air bronchograms is the hallmark ultrasound finding of pneumonia, representing fluid-filled alveoli with patent airways 5.
Why A is incorrect: A-lines with normal lung sliding indicate normal aerated lung, arguing against pneumonia 5.
Why C is incorrect: Bilateral diffuse B-lines suggest interstitial processes (pulmonary edema, interstitial lung disease) rather than focal consolidative pneumonia 5.
Why D is incorrect: Pleural effusion alone is nonspecific and can occur with many conditions. Without parenchymal consolidation, it does not confirm pneumonia 5.
Why E is incorrect: Absent lung sliding with A-lines suggests pneumothorax, not pneumonia 5.
Key Clinical Pitfall: Lung ultrasound is operator-dependent. Consolidation must be distinguished from atelectasis and other causes of hypoechoic lung tissue 5.
Question 6: Answer D
Correct Answer: D. Anti-pseudomonal beta-lactam plus fluoroquinolone
Learning Objective: Identify risk factors for multidrug-resistant organisms in CAP and select appropriate empiric antibiotic coverage.
Cognitive Level: Application/Synthesis (Bloom's Level 3-4)
Explanation:
This patient has risk factors for Pseudomonas aeruginosa: COPD and prior hospitalization with mechanical ventilation 1. The 2019 ATS/IDSA guidelines recommend anti-pseudomonal coverage for patients with these risk factors 1.
Why D is correct: Anti-pseudomonal beta-lactams (piperacillin-tazobactam, cefepime, meropenem) plus either a fluoroquinolone or aminoglycoside plus azithromycin provide appropriate coverage for Pseudomonas and other typical CAP pathogens 1, 7.
Why A is incorrect: Amoxicillin lacks Pseudomonas coverage and is inadequate for this high-risk patient 1.
Why B is incorrect: Doxycycline monotherapy does not cover Pseudomonas and is insufficient for severe CAP with risk factors 1.
Why C is incorrect: Standard beta-lactams (e.g., ceftriaxone, ampicillin-sulbactam) do not reliably cover Pseudomonas 1.
Why E is incorrect: Fluoroquinolone monotherapy may be inadequate for severe CAP and does not provide optimal Pseudomonas coverage as monotherapy 1.
Key Clinical Pitfall: Always assess for risk factors for resistant organisms: prior antibiotics, recent hospitalization, structural lung disease, immunosuppression 1, 7.
Question 7: Answer B
Correct Answer: B. Increased risk of complications and treatment failure
Learning Objective: Interpret C-reactive protein trends in pneumonia management and recognize markers of treatment failure.
Cognitive Level: Analysis/Evaluation (Bloom's Level 4)
Explanation:
Failure of CRP to decline by >50% by day 4 is associated with increased risk of complications, need for intensive support, and mortality 3. This patient's CRP has decreased by only 9%, indicating inadequate response.
Why B is correct: CRP decline <50% by day 4 predicts poor outcomes and should prompt reassessment for complications (empyema, abscess, resistant organisms, alternative diagnosis) 3.
Why A is incorrect: This CRP trend is abnormal and concerning, not a normal response. Most patients show >50% decline by day 3-4 3.
Why C is incorrect: While antibiotic resistance is possible, the CRP trend alone does not confirm this. Further investigation (imaging, cultures, clinical assessment) is needed before changing antibiotics 3.
Why D is incorrect: High admission CRP (>100 mg/L) and persistent elevation suggest bacterial infection, not viral etiology 3.
Why E is incorrect: While laboratory error is possible, this degree of elevation with minimal change is clinically significant and should not be dismissed 3.
Key Clinical Pitfall: Use CRP trends to guide management. Persistent elevation warrants investigation for complications, not just antibiotic escalation 3.
Question 8: Answer C
Correct Answer: C. 4-6 weeks after diagnosis
Learning Objective: Understand the rationale and timing for follow-up imaging in community-acquired pneumonia, particularly in high-risk patients.
Cognitive Level: Application/Analysis (Bloom's Level 3)
Explanation:
Follow-up chest imaging at 4-6 weeks is recommended for patients with risk factors for underlying malignancy, particularly smokers over 50 1. This ensures radiographic resolution and excludes post-obstructive pneumonia from lung cancer.
Why C is correct: The 2019 ATS/IDSA guidelines recommend follow-up imaging 4-6 weeks after diagnosis for patients with risk factors for malignancy (age >50, smoking history) to ensure complete resolution and exclude underlying lesions 1.
Why A is incorrect: Immediate post-treatment imaging is too early. Radiographic resolution lags behind clinical improvement by several weeks 1.
Why B is incorrect: Two weeks is still too early for complete radiographic resolution in most patients 1.
Why D is incorrect: Three months is unnecessarily delayed. If an underlying malignancy is present, earlier detection is preferable 1.
Why E is incorrect: Despite symptom resolution, this patient's smoking history and age mandate follow-up imaging to exclude malignancy 1.
Key Clinical Pitfall: Never skip follow-up imaging in smokers over 50. Up to 10% may have underlying lung cancer presenting as pneumonia 1.
Question 9: Answer B
Correct Answer: B. Chest tube drainage plus antibiotics
Learning Objective: Recognize complicated parapneumonic effusion/empyema and apply appropriate management strategies.
Cognitive Level: Application/Synthesis (Bloom's Level 3-4)
Explanation:
This patient has a complicated parapneumonic effusion (pH <7.2, low glucose, high LDH, cloudy appearance) requiring drainage 3, 8. Antibiotics alone are insufficient.
Why B is correct: Complicated parapneumonic effusions with pH <7.2 require chest tube drainage in addition to antibiotics to prevent progression to empyema and fibrothorax 3, 8. Early drainage improves outcomes and reduces need for surgery.
Why A is incorrect: Antibiotics alone will not adequately treat a complicated effusion. Drainage is essential 3.
Why C is incorrect: Increasing antibiotics and adding corticosteroids does not address the loculated infected fluid requiring mechanical drainage 3.
Why D is incorrect: Therapeutic thoracentesis alone is inadequate for complicated effusions, which require continuous drainage via chest tube 3.
Why E is incorrect: While surgery may eventually be needed if chest tube drainage fails, it is not the first-line intervention. Initial management is chest tube drainage 3, 8.
Key Clinical Pitfall: Do not delay drainage in complicated effusions. pH <7.2, glucose <2.2 mmol/L, or positive Gram stain/culture mandate chest tube placement 3, 8.
Question 10: Answer B
Correct Answer: B. Admit to hospital ward
Learning Objective: Integrate multiple severity markers beyond CURB-65 to make appropriate site-of-care decisions in community-acquired pneumonia.
Cognitive Level: Analysis/Synthesis (Bloom's Level 4)
Explanation:
Despite a CURB-65 score of 1, the elevated lactate (>2 mmol/L) indicates increased severity and mortality risk, warranting hospital admission 3, 4. Lactate is an important adjunct to traditional severity scores.
Why B is correct: Serum lactate ≥2 mmol/L is associated with increased mortality and need for intensive support, even when CURB-65 is low 3. This patient requires inpatient monitoring and intravenous antibiotics initially.
Why A is incorrect: The elevated lactate (3.2 mmol/L) indicates higher severity than CURB-65 suggests. Discharge would be inappropriate 3.
Why C is incorrect: While the lactate is elevated, the patient is hemodynamically stable without respiratory failure. Ward-level care is appropriate initially with close monitoring 3.
Why D is incorrect: Observation followed by discharge ignores the prognostic significance of elevated lactate 3.
Why E is incorrect: ICU admission is not immediately indicated. The patient is not in shock, does not require mechanical ventilation, and has no evidence of multi-organ failure 4, 8.
Key Clinical Pitfall: CURB-65 alone can miss high-risk patients. Always incorporate lactate, oxygen requirements, and clinical judgment into severity assessment 3, 4. Lactate >2 mmol/L should prompt admission even with low CURB-65 scores.