Updated: 7/30/2022

Community-Acquired Pneumonia

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  • Snapshot
    • An 88-year-old man presents to the emergency department from home after developing increasing shortness of breath, fatigue, poor appetite, and malaise. His symptoms began approximately 4 days ago, when he noticed he had a productive cough with green-yellow sputum. His temperature is 101°F (38.3°C), blood pressure is 136/93 mmHg, pulse is 101/min, and respirations are 22/min. Physical exam is notable for crackles in the right lower lobe and dullness to percussion. Chest radiography demonstrates a lobar consolidation.
  • Introduction
    • Definition
      • pulmonary parenchymal infection of the lower respiratory tract acquired outside the healthcare setting
  • Epidemiology
    • Incidence
      • a leading cause of morbidity and mortality worldwide
    • Risk factors
      • chronic lung disease (e.g., chronic obstructive pulmonary disease [COPD])
      • diabetes mellitus
      • proton pump inhibitors
      • smoking
      • high alcohol consumption
      • aspiration
  • Etiology
    • Bacterial
      • Streptococcus pneumoniae (most common)
      • Staphylococcus aureus (seen postinfluenza)
      • Mycoplasma pneumoniae (in young patients)
      • Chlamydophila pneumoniae (in young patients)
      • Legionella species(in elderly patients, immunocomprosed, and smokers)
      • Hemophilus influenzae (in COPD)
      • Moraxella catarrhalis (in COPD)
      • Mixed flora, especially anaerobes like Klebsiella pneumoniae (in alcohol use disorder and aspiration)
    • Viral
      • influenza
      • respiratory syncytial virus
      • rhinovirus
      • parainfluenza virus
      • coronavirus
    • Fungal
      • pneumocystis jiroveci (in patients with HIV)
  • Presentation
    • Symptoms
      • productive or non-productive cough
      • dyspnea
      • pleuritic chest pain
      • fatigue and malaise
    • Physical exam
      • fever
      • tachypnea
      • increased work of breathing
      • pulmonary auscultation
        • rales/crackles
        • rhonchi
      • tactile fremitus
      • egophony
      • dullness to percussion
  • Imaging
    • Radiography of the chest
      • findings
        • lobar consolidation
        • pleural effusion
        • cavitary lesions
  • Studies
    • Sputum Gram stain and culture
    • Blood cultures
      • acquire before administering antibiotics
    • Other studies depend on clinical suspicion, such as
      • urine legionella antigen testing
      • induced sputum acid-fast bacillus stain and myocbacterial culture for tuberculosis
      • direct fluorescent-antibody or PCR testing of a nasopharyngeal swab or sputum for viral causes
      • procalcitonin
        • elevated in bacterial pneumonia
          • useful in differentiating bacterial vs. viral pneumonia
    • Bronchoscopy is considered in
      • critically ill patients
      • patients who fail to respond to therapy
      • chronic pneumonia
      • immunosuppressed
  • Differential
    • COPD exacerbation
      • differentiating factor
        • patient has a history of COPD
  • Treatment
    • Prevention
      • PPSV23 in
        • > 65 years of age
        • 19-64 with chronic medical conditions such as
          • asplenia
          • immunocompromised
          • smokers
      • PCV13 in
        • all children and young patients
      • yearly influenza vaccination
      • incentive spirometry
      • proper oral hygiene
        • tooth brushing, denture care, and fixing dental caries
          • oral flora contains gram-positive, gram-negative, and anaerobic bacteria
      • reducing number of medications that decrease salivation since this has a protective effect on oral bacteria
      • proper positioning
        • upright sitting during eating or at least have bed be set at > 30°of incline
          • especially during comatose states
    • Medical
      • empiric antibiotics in the outpatient setting
        • medications
          • amoxicillin clavulinic acid
            • can add one of the following
              • azythromycin
              • doxycycline
      • empiric antibiotics in the inpatient setting
        • medications
          • levofloxacin or moxifloxacin
          • ceftriaxone and azithromycin
          • if aspiration
            • cover for anaerobes
              • clindamycin or ampicillin-sulbactam
  • Complications
    • Respiratory failure
    • Sepsis
    • Septic shock
    • Empyema
      • requires both drainage and antibiotics for successful treatment
  • Prognosis
    • Improved mortality with administration of antibiotics
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(M2.ID.15.4671) A 78-year-old female is brought to her primary care doctor by her daughter after developing worsening cough, shortness of breath, and shaking chills over the past 3 days. The patient's cough has not produced any sputum. She also complains of alternating feelings of being 'hot then cold.' Whenever she coughs or breathes deeply, she experiences a severe sharp pain in her chest. The patient lives at home with her daughter and is otherwise healthy. Her past medical history is significant for hypertension treated with losartan and hyperlipidemia managed with atorvastatin. The patient does not have a history of tobacco use. Vital signs recorded in the office are as follows: T 38.7, HR 101, BP 135/78, RR 16, and SpO2 94%. Physical exam is significant for crackles in the right upper lung field. The patient is transferred to the local emergency department for further evaluation and management and a chest radiograph is obtained (Figure A). Which of the following is the most likely causative organism in this patient's presentation?

QID: 107173

Group A streptococcus



Klebsiella pneumoniae



Escherichia coli



Streptococcus pneumoniae



Pseudomonas aeruginosa



M 6 D

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(M2.ID.14.87) A 56-year-old previously healthy woman with no other past medical history is post-operative day one from an open reduction and internal fixation of a fractured right radius and ulna after a motor vehicle accident. What is one of the primary ways of preventing postoperative pneumonia in this patient?

QID: 106160

In-hospital intravenous antibiotics



Outpatient oral antibiotics



Hyperbaric oxygenation



Incentive spirometry



Shallow breathing exercises



M 7 E

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