CAP, Hospitalized

[Am J Respir Crit Care Med 2019;200: e45-67, NICE guideline]

 

- Calculation of CRB-65, CURB-65 score, or Pneumonia Severity Index (PSI) is recommended to help determine severity, site of care and mortality risk.

 

- Investigations:

  • CBC with differential, random glucose, electrolytes, creatinine, ALT
  • Chest x-ray, PA and lateral
  • Sputum Gram stain and C&S for patients with productive cough. For organism - specific recommendations, see Treatment of Culture-proven Pneumonia
  • Blood cultures
  • Nasopharyngeal (NP) swab/aspirate for respiratory virus PCR
  • Sputum/NP sample for M. pneumoniae, C. pneumoniae, Legionella PCR.
  • Legionella pneumophila urine antigen if severe CAP or epidemiological risk
  • Consider mycobacterial/fungal culture if relevant history/travel, and PCP (P. jirovecii) in immunocompromised.
  • Arterial blood gas on room air, or on baseline O2 if patient receiving chronic oxygen

- Antibiotic therapy should be administered as soon as possible after the diagnosis is considered likely. This is especially important in the elderly.

 

Nonsevere

Usual Pathogens

S. pneumoniae
H. influenzae
S. aureus
Group A Streptococci
Enterobacterales
Legionella spp
Chlamydia pneumoniae

 

Therapy Dose Duration
Ceftriaxone 1g IV daily 3-5 days

If CRB-65 score 1 and significant co-morbidity, or CRB-65 score 2, add:

 

 
[Azithromycin 500mg IV/PO daily 3 days
or    
Clarithromycin 500mg PO bid or

3-5 days

  XL 1g PO daily  
or    

Doxycycline] 

200mg PO once, then

3-5 days

 

100mg PO bid

 

Alternative

Therapy Dose Duration
Levofloxacin IV/PO 750mg PO/IV daily

3-5 days

 

Severe

- See criteria below, or based on clinical judgement and guided by CRB-65 score 3 or 4 or CURB-65 3-5 or PSI score IV or V.

 

Severe CAP = 1 major criterion or 3 or more minor criteria:

 

Major criteria:

  • septic shock requiring vasopressors
  • respiratory failure requiring mechanical ventilation

Minor criteria:

  • respiratory rate ≥ 30 breaths/minute
  • PaO2 /FiO2 ratio ≤ 250
  • multilobar infiltrates
  • confusion/disorientation
  • urea > 7mmol/L
  • leukopenia (< 4 x 109/L)
  • thrombocytopenia (< 100 x 109/L)
  • hypothermia (< 36°C)
  • hypotension requiring aggressive fluid resuscitation

- If deterioration or persistent respiratory/systemic symptoms, consider the following etiologies (depending on epidemiologic setting/risk factors):

  • Viral pneumonia, including influenza, SARS-CoV-2, and Hantavirus
  • Legionella spp
  • Mycobacterium tuberculosis
  • Chlamydophila psittaci
  • Coxiella burnetti (Q fever)
  • Francisella tularensis (tularemia)
  • Endemic fungi (Histoplasma capsulatum, Coccidioides immitis, Cryptococcus neoformans, Blastomyces spp)
  • Pneumocystis jirovecii

Corticosteroid therapy

- Routine use of corticosteroids in severe CAP not recommended, unless associated with refractory septic shock.

 

Antibiotic therapy

- The standard of care is with a β-lactam + macrolide. Combination therapy is associated with decreased mortality. 

 
Usual Pathogens

S. pneumoniae
H. influenzae
S. aureus/MRSA
Group A Streptococci
Enterobacterales
Legionella spp
Chlamydia pneumoniae

 

Uncommon: 

P. aeruginosa

 

Consider viral:

Influenza

SARS-CoV-2

 

Therapy Dose Duration
Ceftriaxone 1g IV daily

5 days

+    
Azithromycin 500mg IV daily

3-5 days

If MRSA suspected, add:

Therapy Dose Duration

Vancomycin

25-30mg/kg IV once then 15mg/kg IV q8-12h 7 days (minimum 14 days for confirmed MRSA bacteremia)
or    
Linezolid 600mg IV/PO q12h 7 days (minimum 14 days for confirmed MRSA bacteremia)

If P. aeruginosa suspected:

Therapy Dose Duration
Piperacillin-tazobactam 4.5g IV q6h 7 days
+    
Azithromycin 500mg IV daily

3-5 days

Ceftriaxone allergy

Therapy Dose Duration
Levofloxacin 750mg IV daily

5 days

If MRSA suspected, add:    
Vancomycin 25-30mg/kg IV once then 15mg/kg IV q8-12h 7 days (minimum 14 days for confirmed MRSA bacteremia)
or    
Linezolid 600g IV/PO q12h 7 days (minimum 14 days for confirmed MRSA bacteremia)