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

Treatment Guidelines for Community-Acquired Pneumonia (CAP)

For optimal patient outcomes, community-acquired pneumonia should be treated with specific antibiotic regimens based on severity, with empiric therapy initiated promptly while in the emergency department for hospitalized patients. 1

Initial Assessment and Treatment Setting

• Severity assessment should guide the decision for outpatient versus inpatient treatment, with tools like CURB-65 helping to identify patients who may be safely treated as outpatients 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
• Empiric antibiotic therapy should be initiated in adults with clinically suspected and radiographically confirmed CAP regardless of initial serum procalcitonin level 1

Outpatient Treatment

• Preferred treatment: Amoxicillin at higher doses than previously recommended is the preferred agent for outpatient treatment of CAP 1
• Alternative treatment: A macrolide (erythromycin or clarithromycin) is recommended as an alternative choice and for patients with penicillin allergies 1
• For patients referred to hospital with suspected CAP, general practitioners should consider administering antibiotics immediately if the illness is considered life-threatening or if admission delays are expected (over 2 hours) 1

Non-Severe Inpatient Treatment

• Preferred regimen: Combined oral therapy with amoxicillin and a macrolide (erythromycin or clarithromycin) is preferred for patients requiring hospital admission for clinical reasons 1
• Most non-severe inpatients can be adequately treated with oral antibiotics 1
• When oral treatment is contraindicated, recommended parenteral choices include intravenous ampicillin or benzylpenicillin, together with erythromycin or clarithromycin 1
• Alternative regimen: A respiratory fluoroquinolone (levofloxacin) may provide a useful alternative for those intolerant of penicillins or macrolides 1

Severe Inpatient Treatment

• Patients with severe pneumonia should be treated immediately after diagnosis with parenteral antibiotics 1
• Standard regimen: β-lactam plus macrolide or β-lactam plus respiratory fluoroquinolone 1
• For Pseudomonas infection, use an antipneumococcal, antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin or levofloxacin (750-mg dose) 1
• For community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection, add vancomycin or linezolid 1

Duration of Therapy

• Patients with CAP should be treated for a minimum of 5 days 1
• Patients should be afebrile for 48–72 hours and have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy 1
• Recent evidence supports shorter durations (3 days) for young patients with few comorbidities who show clinical improvement by day 3 2
• A longer duration of therapy may be needed if initial therapy was not active against the identified pathogen or if complicated by extrapulmonary infection 1

Switching from IV to Oral Therapy

• Patients should be switched from intravenous to oral therapy when they are:
  • Hemodynamically stable and improving clinically
  • Able to ingest medications
  • Have a normally functioning gastrointestinal tract 1
• Patients should be discharged as soon as they are clinically stable, have no other active medical problems, and have a safe environment for continued care 1
• Inpatient observation while receiving oral therapy is not necessary 1

Pathogen-Directed Therapy

• Once the etiology of CAP has been identified using reliable microbiological methods, antimicrobial therapy should be directed at that specific pathogen 1
• Early treatment (within 48 hours of symptom onset) is recommended 1

Special Considerations

• For patients with hypoxemia or respiratory distress, a cautious trial of noninvasive ventilation is recommended unless immediate intubation is required due to severe hypoxemia 1
• Low-tidal-volume ventilation (6 cm³/kg of ideal body weight) should be used for patients undergoing ventilation who have diffuse bilateral pneumonia or acute respiratory distress syndrome 1
• Patients with CAP who have persistent septic shock despite adequate fluid resuscitation should be considered for treatment with drotrecogin alfa activated within 24 hours of admission 1
• Hypotensive, fluid-resuscitated patients with severe CAP should be screened for occult adrenal insufficiency 1

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
• The chest radiograph need not be repeated prior to hospital discharge in those who have made a satisfactory clinical recovery 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 (especially smokers and those over 50 years) 1

Common Pitfalls to Avoid

• Unnecessary hospitalization of low-risk patients (CURB-65 score of 0 or 1 without hypoxemia) increases healthcare costs and risks of hospital-acquired infections 3
• Overuse of broad-spectrum antibiotics when narrower-spectrum options would be effective contributes to antimicrobial resistance 3
• Treatment durations are often longer than necessary, with a median of 10 days in practice despite guidelines recommending 5-7 days for uncomplicated cases 3
• Respiratory fluoroquinolones should not be used as first-line agents for uncomplicated CAP to preserve their effectiveness 1, 4