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

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)

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

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)

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