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Pulmonary Infections

VASP, Evan Schwartz

Acute Bronchitis


  • 1-3 wks productive cough, often preceded by URI, may have wheezing/rhonchi
  • Distinct from chronic bronchitis (>3 mos of consecutive cough x 2 consecutive yrs)
  • Distinct from PNA (parenchymal consolidation, fever >100.4F, hypoxia, tachypnea)
  • DDx: COVID-19, post-nasal drip, GERD, undertreated/new asthma, ACE-i induced bradykinin cough, undertreated CHF, acute PE, or new lung cancer
  • Clinical dx; CXR/labs not necessary unless PNA suspected


  • Supportive: lozenges, cough suppressants (guaifenesin or dextromethorphan), smoking cessation. Consider albuterol inhaler for wheezing
  • No indication for antibiotics



  • Dx often clinical w/cough, sore throat, #sputum/nasal discharge, HA, fever, myalgias, and malaise; ± N/V/D. Exam with increased flushing, rarely with lower respiratory symptoms


  • During flu season: Obtain COVID/RPP or dedicated influenza PCR; testing is more accurate if obtained within 96 hour of symptom onset

  • CXR if concerned for bacterial superinfection


  • Antivirals most effective when given <48 hours from symptom onset; however, recommended to be given if symptomatic despite duration and to all hospitalized patients

  • Oseltamivir 75mg BID x 5 days, peramivir 600mg IV x 1 (needs renal adjustment), or baloxavir (age ≥12) 40mg once (use 80 mg if >80kg)

  • Amantadine and rimantadine are no longer used due to emerging resistance

Community Acquired Pneumonia (CAP)


  • All PNA that does not otherwise meet criteria for Hospital Acquired Pneumonia (PNA that develops ≥48 hours after hospital admission), Ventilator Associated Pneumonia (PNA that develops ≥48-72 hours after endotracheal intubation), or aspiration PNA

  • Healthcare-associated pneumonia is no longer a clinical entity per 2016 IDSA guidelines

  • MRSA Risk Factors: recent history, cavitary lesion, post-influenza bacterial PNA, pts with IDU, severe hypoxemia requiring intubation

  • Pseudomonas: Double coverage is not indicated in general population; LVQ has 82% sensitivity so not recommended unless isolate proven susceptible


  • Sputum cultures prior to abx, consider BCx in select groups (severe pneumonia, ICU admission, cavitary disease, immunosuppression).

  • Rule out flu if the right season, COVID-19, consider RVP if it will change management

  • CURB-65 or PSI can aid in decision between outpatient vs inpatient therapy

    • CURB65: Confusion, Uremia (BUN >=19 mg/dL), RR (>30/min), BP(\<90/60 mmHg), Age ≥ 65 If ≥ 2, hospitalization is recommended.
  • Consider urine pneumococcal Ag, urine Legionella Ag in severe CAP and in certain pts (e.g., neutropenia, asplenia, obstructive lung disease, hyponatremia, diarrhea, or heavy alcohol use); these are performed at reference labs and will take several days to return.

  • CRP, ESR, and pro-calcitonin have not been shown to reliably improve outcomes; however, pro-calcitonin \< 0.25 suggests against bacterial respiratory infection and antibiotic discontinuation is encouraged

  • PA/ lateral CXR to evaluate for and localize infiltrate. If immunocompromised, consider CT chest w/o contrast (does not improve outcomes)

    • Lobar Consolidation - likely bacterial
    • Interstitial Infiltrate - likely atypical vs. viral vs. non-infectious
    • Cavitation - concerning for fungal vs. necrotizing vs. mycobacterial


  • Antibiotic Duration: 5-7 days (at least 5 days and improvement with clinical stability)


Inpatient (Non- ICU & ICU)

No MRSA or Pseudomonas suspected

Low Risk\*:

-Amoxicillin 1g TID

High Risk:

-Amoxicillin-clavulanate 875/125 BID + Macrolide

-Cefdinir 300 BID + Macrolide

-Amoxicillin 1g TID + Macrolide

-Levofloxacin 750 daily

CTX 2g q24 + Azithromycin 500 daily OR Levofloxacin 750 daily
MRSA or Pseudomonas suspected

MRSA: Vancomycin OR Linezolid

(if no bacteremia)

Pseudomonas: Cefepime 2g q8h

*No chronic heart, lung, liver, renal disease, DM, alcoholism, immunocompromise

Additional Information

  • MRSA nasal swab has reported negative predictive value for MRSA pneumonia ranging 95% to >99%; consider sending and if negative, discontinue MRSA agent

  • CTX is generally adequate coverage for aspiration PNA without evidence of abscess, empyema, or cavitary lesion on imaging

  • Aspiration pneumonia can be confused for aspiration pneumonitis which does not need to be treated with antibiotics. Rapid resolution of leukocytosis and stabilization of vitals suggest aspiration pneumonitis and consideration of stopping antibiotics.

  • There is low sensitivity of S. pneumoniae to azithromycin (42%) and doxycycline (72%), so these should not be used as monotherapy

  • Check for drug interactions with linezolid (e.g., SSRI, methadone, methamphetamine use)

Hospital Acquired Pneumonia (HAP) and Ventilator Associated Pneumonia (VAP)


  • HAP: Pneumonia that develops >48 hours after admission

  • VAP: Pneumonia that develops >48 hours after endotracheal intubation


  • Cultures of blood, sputum, endotracheal aspirate and/or bronchoscopy specimen

  • Consider MRSA nares to help with de-escalation

  • If there is concern for respiratory viruses: send influenza, COVID, RVP


  • Initially cover for MRSA and Pseudomonas

  • Antibiotic Duration: 7 days in uncomplicated cases, although specific pathogens (e.g., Pseudomonas) may require longer duration and ID guidance

  • Consider ID consultation if the patient is not clinically improving on empiric therapy or if an MDR pathogen grows from culture

  • If no MRSA isolated and pt is improving, consider stopping vancomycin ASAP

  • There is concern for nephrotoxicity with combination Vancomycin and piperacillin-tazobactam, but data controversial

MRSA Coverage

Pseudomonas Coverage

First Line Vancomycin (Pharmacy dosing) Cefepime 2g q8h OR Piperacillin-tazobactam 3.375 q8h extended infusion OR Ceftazidime 2g q8h
Alternative Vancomycin allergy: Linezolid 600 mg PO q12h True PCN allergy: Aztreonam 2g q8h

Last update: 2022-06-23 02:39:05