What is the treatment approach for community-acquired pneumonia (CAP)?

Treatment of Community-Acquired Pneumonia (CAP)

The recommended treatment for community-acquired pneumonia should be guided by severity assessment using tools like CURB-65 or Pneumonia Severity Index (PSI), with specific antibiotic regimens tailored to outpatient, non-severe inpatient, or severe cases requiring ICU care. 1

Initial Assessment and Site of Care Decision

• Severity assessment should guide the decision between outpatient versus inpatient treatment using CURB-65 or PSI 1
• A 3-step process is recommended: (1) assess preexisting conditions that compromise home care safety; (2) calculate PSI with recommendation for home care for risk classes I, II, and III; and (3) apply clinical judgment 1
• For patients admitted through the emergency department, the first antibiotic dose should be administered while still in the ED 1
• All admitted patients should receive their first dose of antibiotic therapy within 8 hours of hospital arrival 1

Outpatient Treatment

• For previously healthy adults without comorbidities or recent antibiotic use, amoxicillin 1 g three times daily is the first choice 1
• For adults with comorbidities, an advanced macrolide or a respiratory fluoroquinolone is recommended 1
• Azithromycin is effective for community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, or Streptococcus pneumoniae in patients appropriate for oral therapy 2

Non-Severe Inpatient Treatment (Medical Ward)

• Preferred regimen is β-lactam (ampicillin/sulbactam, cefotaxime, ceftriaxone, or ceftaroline) PLUS a macrolide (azithromycin or clarithromycin) 1
• Most non-severe inpatients can be adequately treated with oral antibiotics when clinically appropriate 1
• For azithromycin dosing in adults with CAP: 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 2

Severe CAP Requiring ICU Care

• For patients without risk factors for Pseudomonas aeruginosa: non-antipseudomonal β-lactam (ceftriaxone, cefotaxime) PLUS either a macrolide or a respiratory fluoroquinolone 1
• For patients with risk factors for Pseudomonas aeruginosa: antipseudomonal β-lactam (cefepime, ceftazidime, piperacillin-tazobactam, meropenem) PLUS either ciprofloxacin OR a macrolide plus aminoglycoside 1
• N-acetylcysteine is not currently recommended as adjunct treatment for patients with severe CAP 3

Duration of Therapy and Transition to Oral Therapy

• Duration of therapy is generally 5-7 days for responding patients 1
• Patients should be switched from intravenous to oral therapy when they are hemodynamically stable and improving clinically 1
• Criteria for switch to oral therapy include: improvement in cough and dyspnea, afebrile status, decreasing white blood cell count, and functioning gastrointestinal tract with adequate oral intake 1
• Early conversion to oral therapy has not been associated with increased complications or higher mortality 4

Special Considerations

• For suspected or confirmed Legionella, treatment options include respiratory fluoroquinolone (levofloxacin preferred) or macrolide (azithromycin preferred) 1
• For Mycoplasma or Chlamydophila, treatment options include macrolide, doxycycline, or respiratory fluoroquinolone 1
• Azithromycin should not be used in patients with pneumonia who are inappropriate for oral therapy due to moderate to severe illness or specific risk factors 2
• Providers should consider the risk of QT prolongation with azithromycin, which can be fatal in at-risk groups including those with known QT prolongation, history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias, or uncompensated heart failure 2

Pediatric Treatment

• For children with CAP, azithromycin dosing is based on weight: 10 mg/kg as a single dose on the first day followed by 5 mg/kg on Days 2 through 5 2
• For acute otitis media in children, alternative dosing options include 30 mg/kg as a single dose or 10 mg/kg once daily for 3 days 2

Common Pitfalls and Caveats

• Delayed antibiotic administration can increase mortality; ensure timely administration 1
• Inadequate coverage of causative pathogens is associated with worse outcomes 1
• For patients who fail to improve as expected, conduct a careful review of the clinical history, examination, prescription chart, and results of all available investigations 1
• Up to 10% of all CAP patients will not respond to initial therapy, requiring diagnostic evaluation for drug-resistant or unusual pathogens, nonpneumonia diagnoses, or pneumonia complications 1
• Monitor for Clostridium difficile-associated diarrhea, which can range from mild diarrhea to fatal colitis 2
• Be alert for hypersensitivity reactions to azithromycin, including angioedema, anaphylaxis, and severe dermatologic reactions 2

Follow-up

• Clinical review should be arranged for all patients at around 6 weeks, either with their general practitioner or in a hospital clinic 1
• A chest radiograph should be arranged at follow-up for patients with persistent symptoms or physical signs, or who are at higher risk of underlying malignancy 1
• Pneumonia can be prevented by pneumococcal and influenza vaccines in appropriate at-risk populations 1