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    Community Acquired Pneumonia (Adult) – Treatment

    Infections, Respiratory

    Last Updated Aug 26, 2020
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    • 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.

    Recommended Treatment

    General Treatment

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


    • 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.

    Criteria For Hospital Admission

    • 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.

    Criteria For Close Observation And/or Consult

    • 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.

    Quality Of Evidence?


    Evidence relies on American Thoracic Society updated guidelines on CAP from 2019 as well as other sources all produced in the last few years.


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