• Severity assessment helps determine management location and antibiotic choice.
• In immunocompetent adults:
  • Typical Bacteria: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus.
  • Atypical Bacteria: Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella species.
  • Viral: Influenza A/B, respiratory syncytial virus, adenovirus, parainfluenza, coronavirus (see BC EMN: Covid-19).
• Always consider sepsis.

General Treatment

•  Oxygen if SpO₂ < 94% (if at risk for hypercapnia then only if SpO₂ < 88%).
• IV fluids – concern of early sepsis/dehydration.
• Acetaminophen.

Antibiotics

• Spectrum App.
• Be aware of local resistance patterns.
• Consider patient risk factors, including recent antibiotic use.
•  Comorbidities:
  • Chronic heart, lung, liver, or renal disease.
  • Diabetes.
  • Alcoholism.
  • Malignancy.
  • Asplenia.
• Treatment length = 5 days minimum and clinically stable without fever for 48 hrs.
• Low Severity CAP (eg. CURB-65 = 0-1):
  • WITHOUT Comorbidities:
    • Amoxicillin 1g TID PO, or
    • Doxycycline 100mg BID PO, or
    • Macrolide:
      • Clarithromycin 500mg BID PO -OR- Azithromycin 500mg on first day then 250mg daily PO.
  • WITH Comorbidities:
    • Beta Lactam AND Macrolide:
      • AMOX-CLAV 875/125mg BID PO -OR- Cefuroxime 500mg BID PO
      • Clarithromycin 500mg BID PO -OR- Azithromycin 500mg on first day then 250mg daily PO, or
    • Beta Lactam AND Doxycycline:
      • AMOX-CLAV 875/125mg BID PO -OR- Cefuroxime 500mg BID PO
      • Doxycycline 100mg BID PO, or
    • Fluoroquinolone:
      • Moxifloxacin 400 mg daily PO -OR- Levofloxacin 750mg daily PO.
•  Moderate Severity CAP (eg. CURB-65 = 2):
  • Beta Lactam AND Macrolide:
    • Ceftriaxone 1-2g daily IV -OR- AMOX-CLAV 875mg BID PO.
    • Azithromycin 500mg daily IV/PO, or
  • Fluoroquinolone:
    • Moxifloxacin 400 mg daily IV/PO -OR- Levofloxacin 750mg daily IV/PO.
• High Severity CAP (eg. CURB-65 = 3-5):
  • Beta Lactam AND Macrolide:
    • Ceftriaxone IV 1-2g daily.
    • Azithromycin IV 500mg daily, or
  • Beta Lactam AND Fluoroquinolone:
    • Ceftriaxone IV 1-2g daily.
    • Moxifloxacin IV 400mg daily -OR- Levofloxacin IV 750mg daily.
• Risk of MRSA or Pseudomonas
  • Locally validated risk factors are best for determining this risk.
  • Risk factors include:
    • prior infection with MRSA or Pseudomonas, or
    • hospitalization involving IV antibiotics within the last 90 days.
  • MRSA = ADD Vancomycin.
    • Loading dose:
      • 25-30 mg/kg IV single dose (based on actual body weight; no maximum dose).
    • Maintenance dose:
      • 15 mg/kg IV dose q8-12 hours (based on actual body weight, maximum of 2 g/dose).
      • For doses >500 mg – round to nearest 250 mg.
  • Pseudomonas = INCLUDE Anti-pseudomonal B-Lactam.
    • Piperacillin-Tazobactam (4.5g IV q6h).
    • Cefepime (2g IV q8h).
    • Imipenem (500mg IV q6h) -OR- Meropenem (1g IV q8h).

Aspiration Pneumonia

• Attempt to differentiate from aspiration pneumonitis which does not require antibiotics.
• Airway management – consult ICU or respiratory therapist if needed.
• Routinely include gram negative coverage.
  • Ceftriaxone 1-2g IV daily -OR- Levofloxacin IV/PO 750mg daily
• Include anaerobic coverage if: lung abscess, necrotizing pneumonia, empyema or poor dentition.
  • AMOX-CLAV 875/125mg BID PO -OR- Moxifloxacin IV/PO 400mg daily
• Risk of Pseudomonas – Antipseudomonal B-Lactam with anaerobic coverage
  • Piperacillin-Tazobactam (4.5g IV q6h) -OR- Meropenem (1g IV q8h)
• Risk of MRSA – ADD vancomycin as outlined above.
• Consider drainage of empyema or lung abscess for diagnosis and therapy.
• Treatment length = 5-7 days if good clinical response; longer if anaerobes suspected.

• Use of a prognosis clinical prediction rule, in addition to clinical judgement, is recommended for admission vs outpatient treatment.
  • Pneumonia Severity Index (PSI)
    • Useful tool which provides an excellent risk stratification. For most patients however, the CURB-65 is easier to use and requires fewer inputs.
  • CURB-65
    • Confusion, BUN > 7 mmol/L, RR > 30, SBP < 90 or DBP < 60 mmHg, Age > 65.
    • 0-1 Outpatient, 2 Inpatient, 3+ Consider ICU.
• Considerations also include patient’s ability and reliability to take oral medications, their social circumstances and medical comorbidities.
• Discharged patients should have follow-up within 2 days.

• Patients requiring vasopressors or ventilation should be admitted to the ICU.
• Consider ICU admission for any severe CAP (eg. CURB-65 = 3-5).
• Consider transport when a higher level of care than your center provides may be required.

1. Metlay, J. P., Waterer, G. W., Long, A. C., Anzueto, A., Brozek, J., Crothers, K., … & Whitney, C. G. (2019). Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. American journal of respiratory and critical care medicine, 200(7), e45-e67.

   
   

2. Jonathan Bennet. Community-acquired Pneumonia. BMJ Best Practice. February 2020.

   
   

3. Antimicrobial Stewardship Programme: Innovation, Research, Education, and Safety: VCH COMMUNITY-ACQUIRED PNEUMONIA (CAP) MANAGEMENT GUIDELINES FOR ADULTS. March 2016.

   
   

4. Cameron, P., Little, M., Mitra, B., & Deasy, C. (2020). Textbook of Adult Emergency Medicine, Chapter 6.3 – Community-acquired pneumonia, Pg.272-281

   
   

5. Mandell, L. A., & Niederman, M. S. (2019). Aspiration pneumonia. New England Journal of Medicine, 380(7), 651-663.