What is the management for pneumonia?

Management of Pneumonia

Pneumonia management requires immediate empiric antibiotic therapy tailored to disease severity and setting, with hospitalized patients receiving combination β-lactam plus macrolide therapy and outpatients treated with a macrolide, doxycycline, or respiratory fluoroquinolone. 1

Initial Assessment and Diagnostic Workup

Confirm diagnosis with chest radiography in all patients with suspected pneumonia. 1, 2 The presence of air space density on imaging combined with clinical signs (temperature >38°C or ≤36°C, leukocyte count <4000/μL or >10,000/μL) and symptoms (new or increased cough, dyspnea) establishes the diagnosis. 3

Pre-Treatment Testing

• Obtain blood cultures and sputum for Gram stain and culture before initiating antibiotics in all hospitalized patients, but do not delay treatment. 1, 4
• Test for COVID-19 and influenza when these viruses are circulating in the community, as results affect treatment decisions. 3
• Obtain urinary antigen testing for Legionella pneumophila serogroup 1 and Streptococcus pneumoniae. 4
• Measure complete blood count, renal and liver function tests, electrolytes, and oxygen saturation in hospitalized patients. 1, 2

Severity Assessment

Determine disease severity to guide treatment setting and antibiotic selection. 2 Risk factors for severe disease include:

• Age ≥65 years 1, 4
• Immunosuppression from disease-modifying drugs or biologics 4
• Chronic lung disease, smoking, or functional asplenia 5, 3
• Bacteremia, cystic fibrosis, or nosocomial acquisition 5

Empiric Antibiotic Therapy

Outpatient Management (Previously Healthy)

Treat with a macrolide (azithromycin 500mg daily or clarithromycin), doxycycline, or a respiratory fluoroquinolone (levofloxacin, moxifloxacin). 1, 2 These agents provide coverage against S. pneumoniae, H. influenzae, M. pneumoniae, and C. pneumoniae. 6

Non-ICU Hospitalized Patients

First-line therapy is intravenous ceftriaxone 1-2g daily PLUS azithromycin 500mg daily. 1, 4 This combination provides coverage for both typical and atypical pathogens and has demonstrated mortality benefit. 4

Alternative β-lactams include:

• Cefotaxime 1-2g every 8 hours 1
• Ampicillin-sulbactam 1.5-3g every 6 hours 1

For penicillin-allergic patients, use a respiratory fluoroquinolone (levofloxacin 750mg daily or moxifloxacin) plus aztreonam. 1

ICU Patients with Severe Pneumonia

Administer a β-lactam (ceftriaxone, cefotaxime, or ampicillin-sulbactam) PLUS either azithromycin or a fluoroquinolone. 1, 2 This regimen is strongly recommended over monotherapy because combination therapy reduces mortality in severe CAP. 4

For patients with risk factors for Pseudomonas aeruginosa (structural lung disease, recent broad-spectrum antibiotics, recent hospitalization):

• Use an antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) PLUS either ciprofloxacin or levofloxacin 750mg, OR
• The above β-lactam PLUS an aminoglycoside AND azithromycin 1

For suspected community-acquired MRSA, add vancomycin or linezolid. 1

Hospital-Acquired and Ventilator-Associated Pneumonia

Patients with early-onset HAP/VAP (<5 days) without risk factors for multidrug-resistant pathogens can receive standard therapy. 1

Patients with late-onset disease (≥5 days) or risk factors for MDR pathogens require broad-spectrum therapy covering P. aeruginosa, Acinetobacter, and MRSA. 1 Consider local antibiogram data when selecting empiric therapy. 1

• Use combination therapy with an antipseudomonal β-lactam plus either a fluoroquinolone or aminoglycoside. 1
• Add vancomycin or linezolid for MRSA coverage. 1
• Consider colistin for carbapenem-resistant Acinetobacter. 1

Timing of Antibiotic Administration

Administer the first antibiotic dose in the emergency department immediately upon diagnosis. 1, 2, 4 Delays beyond 4 hours are associated with increased mortality. 4

Transition to Oral Therapy

Switch from intravenous to oral antibiotics when the patient is:

• Hemodynamically stable 1, 2, 4
• Clinically improving 1, 4
• Afebrile for 48-72 hours 4
• Able to ingest medications 1, 4
• Has a normally functioning gastrointestinal tract 1, 4

Discharge patients as soon as they meet these criteria; inpatient observation while receiving oral therapy is unnecessary. 1

Duration of Therapy

Treat for a minimum of 5 days, ensuring the patient is afebrile for 48-72 hours and has no more than one sign of clinical instability before discontinuation. 1, 2, 4

For uncomplicated pneumonia, 7 days of appropriate antibiotics is sufficient. 1, 2

Extend duration to 10-14 days for:

• Legionella, S. aureus, or Gram-negative bacilli pneumonia 1, 4
• Documented bacteremia 4
• Extrapulmonary complications (meningitis, endocarditis) 1, 4

For HAP/VAP, 7-8 days is recommended for patients with good clinical response and no evidence of non-fermenting gram-negative bacilli. 1

De-escalation and Pathogen-Directed Therapy

Once culture results are available, narrow antibiotic therapy to the most specific agent for the identified pathogen. 1 This reduces selective pressure for resistance. 1

Negative lower respiratory tract cultures obtained without recent antibiotic changes can be used to stop therapy. 1

For penicillin-susceptible S. pneumoniae, switch to narrow-spectrum agents like penicillin or amoxicillin. 1

Special Considerations

Influenza-Associated Pneumonia

Treat with oseltamivir (within 48 hours of symptom onset) PLUS antibacterial agents targeting S. pneumoniae and S. aureus. 1, 2 Continue antivirals even beyond 48 hours in hospitalized patients to reduce viral shedding. 1

Severe CAP with Septic Shock

• Consider systemic corticosteroids within 24 hours of admission for patients with severe CAP and septic shock. 3 This may reduce 28-day mortality. 3
• Screen hypotensive, fluid-resuscitated patients for occult adrenal insufficiency. 1, 2

Respiratory Support

• Use noninvasive ventilation for patients with hypoxemia or respiratory distress unless severe hypoxemia (PaO₂/FiO₂ ratio <150) and bilateral infiltrates require immediate intubation. 1
• For ventilated patients with diffuse bilateral pneumonia or ARDS, use low-tidal-volume ventilation (6 mL/kg ideal body weight). 1, 2

Monitoring and Treatment Failure

Review clinical response daily, including temperature, respiratory rate, and hemodynamic parameters. 2

For patients not improving within 3-5 days, consider:

• Incorrect diagnosis 1
• Inappropriate antibiotic, dose, or route 1
• Unusual pathogen or drug-resistant organism 1
• Complications (empyema, pulmonary superinfection) 1

Obtain repeat chest radiograph, CRP, white cell count, and additional microbiological specimens. 1

For non-severe pneumonia failing amoxicillin monotherapy, add or substitute a macrolide. 1 For severe pneumonia not responding to combination therapy, consider adding rifampicin. 1

Critical Pitfalls to Avoid

• Do not use macrolide monotherapy in hospitalized patients due to inadequate β-lactam coverage and rising macrolide resistance. 4
• Do not delay antibiotics for diagnostic testing, as this increases mortality. 4
• Do not continue parenteral antibiotics once oral transition criteria are met. 1
• Monitor renal function and adjust doses for creatinine clearance, particularly with β-lactams and fluoroquinolones. 4
• Be aware of QT prolongation risk with macrolides (especially azithromycin) in patients with cardiac risk factors, electrolyte abnormalities, or concurrent QT-prolonging medications. 5

Prevention

Administer influenza vaccination annually to high-risk groups: those with chronic lung, heart, renal, or liver disease; diabetes; immunosuppression; and adults ≥65 years. 1, 2

Consider pneumococcal vaccination for those at increased risk of pneumococcal infection. 1, 2