What are the guidelines for treating community-acquired pneumonia (CAP)?

Guidelines for Community-Acquired Pneumonia Treatment

The treatment of community-acquired pneumonia (CAP) should be guided by severity assessment using tools like CURB-65 or Pneumonia Severity Index (PSI), with empiric antibiotic therapy tailored to the patient's risk factors and likely pathogens based on treatment setting. 1

Initial Assessment and Site-of-Care Decision

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

Empiric Antibiotic Therapy Recommendations

Outpatient Treatment

• For previously healthy adults without comorbidities or recent antibiotic use: Amoxicillin 1 g three times daily 1
• For adults with comorbidities: An advanced macrolide (azithromycin, clarithromycin) or a respiratory fluoroquinolone 1, 3

Non-Severe Inpatient Treatment (Medical Ward)

• Preferred regimen: β-lactam (ampicillin/sulbactam, cefotaxime, ceftriaxone, or ceftaroline) PLUS a macrolide (azithromycin or clarithromycin) 1
• Alternative: Respiratory fluoroquinolone monotherapy 3
• Most non-severe inpatients can be adequately treated with oral antibiotics when clinically appropriate 1

Severe CAP Requiring ICU Care

• Without risk factors for Pseudomonas aeruginosa: Non-antipseudomonal β-lactam (ceftriaxone, cefotaxime) PLUS either a macrolide or a respiratory fluoroquinolone 1
• With risk factors for Pseudomonas aeruginosa: Antipseudomonal β-lactam (cefepime, ceftazidime, piperacillin-tazobactam, meropenem) PLUS either ciprofloxacin OR a macrolide plus aminoglycoside 1

Duration of Therapy and Transition to Oral Therapy

• Patients with CAP should be treated for a minimum of 5 days 2
• Patients should be afebrile for 48–72 hours and have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy 2
• For uncomplicated cases: 5-7 days of therapy is generally sufficient 1, 3
• For severe cases: 10-14 days of therapy may be needed 3
• For specific pathogens like Legionella, staphylococcal, or gram-negative enteric bacilli pneumonia: Extended to 14-21 days 3
• Criteria for switch to oral therapy include: 1
  • Hemodynamic stability and clinical improvement
  • Improvement in cough and dyspnea
  • Afebrile status
  • Decreasing white blood cell count
  • Functioning gastrointestinal tract with adequate oral intake

Pathogen-Specific Considerations

• For suspected or confirmed Legionella: Respiratory fluoroquinolone (levofloxacin preferred) or macrolide (azithromycin preferred) 1
• For Mycoplasma or Chlamydophila: Macrolide, doxycycline, or respiratory fluoroquinolone 1
• For multi-drug resistant Streptococcus pneumoniae: Levofloxacin has shown 95% clinical and bacteriologic success 4
• Once the etiology of CAP has been identified on the basis of reliable microbiological methods, antimicrobial therapy should be directed at that pathogen 2

Management of Non-Responding Patients

• Up to 15% of patients with CAP may not respond appropriately to initial antibiotic therapy 2
• 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
• A systematic approach to these patients will help determine the cause of failure 2

Prevention Strategies

• Pneumococcal polysaccharide vaccine is recommended for persons 65 years of age and for those with selected high-risk concurrent diseases 2
• Annual influenza immunization is recommended for healthcare workers in inpatient and outpatient settings and long-term care facilities 2
• 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

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
• Streptococcus pneumoniae remains the most common identified cause of CAP requiring hospitalization, whereas Legionella pneumophila is a common cause of severe CAP 5
• Initial therapy with a beta-lactam plus a macrolide or an anti-pneumococcal fluoroquinolone is recommended for all patients with community-acquired pneumonia to ensure coverage of both typical and atypical pathogens 6