Internal Medicine Community-Acquired Pneumonia Questions and Answers

Question 1

A 67-year-old male with a history of COPD and type 2 diabetes presents to an outpatient clinic with a 3-day history of productive cough, fever, and dyspnea. He has not taken antibiotics in the past year. According to the 2019 IDSA/ATS guidelines, which of the following is the most appropriate empiric antibiotic regimen for this patient?

Accepted Answer

Amoxicillin-clavulanate plus doxycycline

Answer

According to the 2019 IDSA/ATS guidelines, outpatients with community-acquired pneumonia (CAP) who have comorbidities (such as chronic lung disease or diabetes) should be treated with either combination therapy or monotherapy with a respiratory fluoroquinolone. [15] Combination therapy consists of a beta-lactam (like amoxicillin-clavulanate) PLUS a macrolide or doxycycline. [11, 15] Macrolide monotherapy is not recommended due to high rates of pneumococcal resistance. Amoxicillin monotherapy is an option for patients without comorbidities. Ciprofloxacin is not a respiratory fluoroquinolone and lacks reliable activity against *Streptococcus pneumoniae*.

Question 2

Which of the following clinical parameters is a component of the CURB-65 score for assessing the severity of community-acquired pneumonia?

Accepted Answer

A respiratory rate ≥ 30 breaths per minute

Answer

The CURB-65 score is an acronym for five clinical features used to predict mortality and determine the site of care for patients with CAP. One point is given for each of the following: Confusion (new onset), Urea > 7 mmol/L (BUN > 19 mg/dL), Respiratory rate ≥ 30 breaths/min, Blood pressure (systolic < 90 mmHg or diastolic ≤ 60 mmHg), and age ≥ 65 years. [1, 2, 6] The other options are indicators of severe pneumonia but are not components of the CURB-65 score.

Question 3

A 58-year-old female with no significant past medical history is admitted to a general medical ward for community-acquired pneumonia. She is hemodynamically stable, with an oxygen saturation of 94% on room air. Which of the following antibiotic regimens is the most appropriate initial empiric therapy?

Accepted Answer

Ceftriaxone plus azithromycin

Answer

For an adult with non-severe community-acquired pneumonia admitted to an inpatient ward, standard empiric therapy should cover both typical and atypical pathogens. The recommended primary regimen is a beta-lactam (e.g., ceftriaxone, ampicillin-sulbactam) combined with a macrolide (e.g., azithromycin). [16, 22] Monotherapy with a respiratory fluoroquinolone (e.g., levofloxacin) is an alternative. Vancomycin and piperacillin-tazobactam provide overly broad coverage for MRSA and Pseudomonas, which is not indicated without specific risk factors. Doxycycline monotherapy is typically reserved for outpatient treatment.

Question 4

A 62-year-old patient is admitted to the ICU with severe community-acquired pneumonia requiring mechanical ventilation. According to the 2019 IDSA/ATS guidelines, which of the following is the strongest indication to add empiric coverage for *Pseudomonas aeruginosa*?

Accepted Answer

Recent hospitalization with receipt of parenteral antibiotics

Answer

The 2019 IDSA/ATS guidelines recommend empiric treatment for *Pseudomonas aeruginosa* in patients with CAP only if locally validated risk factors are present. The most consistently cited major risk factors are prior respiratory isolation of *P. aeruginosa* or recent hospitalization (within 90 days) where the patient received parenteral antibiotics. [19, 21] While nursing home residence was part of the old HCAP definition, it is no longer considered a standalone indication. Alcoholism and ICU admission alone are not specific risk factors for *Pseudomonas*.

Question 5

A 70-year-old man presents with a 4-day history of high fever, a non-productive cough, watery diarrhea, and confusion. He is a retired plumber who recently worked on his home's hot water tank. Laboratory studies are notable for a serum sodium of 127 mEq/L. Which pathogen is the most likely cause of his pneumonia?

Accepted Answer

Legionella pneumophila

Answer

The clinical presentation of pneumonia accompanied by prominent extrapulmonary symptoms, specifically gastrointestinal distress (diarrhea), neurologic symptoms (confusion), and hyponatremia, is highly characteristic of Legionnaires' disease, caused by *Legionella pneumophila*. [4, 20, 27] The exposure to a contaminated water source (hot water tank) further strengthens this diagnosis. While other pathogens can cause pneumonia, this specific constellation of findings is classic for *Legionella*.

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Community-Acquired Pneumonia Questions and Answers