How should I assess severity and select empiric antibiotic therapy for an otherwise healthy adult with community‑acquired pneumonia (CAP) and a CURB‑65 score of 0‑1?

Management of Community-Acquired Pneumonia with CURB-65 Score 0-1

For an otherwise healthy adult with CAP and CURB-65 score 0-1, treat as an outpatient with oral amoxicillin 1 gram three times daily as first-line therapy, or a macrolide (azithromycin or clarithromycin) if penicillin-allergic. 1

Severity Assessment

• Use CURB-65 scoring to stratify mortality risk and guide disposition decisions. 2, 1 The score assigns one point each for: Confusion, Urea >7 mmol/L (BUN >19 mg/dL), Respiratory rate ≥30/min, Blood pressure <90/60 mmHg, and age ≥65 years. 2, 1

• CURB-65 scores of 0-1 indicate low mortality risk (<3%) and qualify for outpatient management. 1 Recent evidence demonstrates that CURB-65 is associated with lower 30-day mortality compared to the Pneumonia Severity Index (PSI) and is more user-friendly in clinical practice. 3

• Pulse oximetry should be performed immediately to assess oxygen saturation and guide oxygen therapy decisions. 2

Empiric Antibiotic Selection for Outpatient Treatment

First-Line Monotherapy (No Comorbidities)

• Amoxicillin 1 gram orally three times daily is the preferred first-line agent. 2, 1, 4 This represents a higher dose than previously recommended to address potential pneumococcal resistance. 2

• Alternative: Doxycycline 100 mg orally twice daily can be used as first-line monotherapy. 1

• Macrolide monotherapy (erythromycin or clarithromycin) is reserved for patients with penicillin hypersensitivity. 2 Do not use macrolide monotherapy in settings where pneumococcal macrolide resistance exceeds 25%. 1

Alternative Regimen

• Levofloxacin 500 mg orally once daily for 5 days provides coverage of both typical and atypical pathogens. 4

• Combination therapy: Amoxicillin 1 gram orally every 8 hours plus azithromycin 500 mg on day 1, followed by 250 mg daily for days 2-5 is an alternative approach. 4

Critical Management Considerations

Diagnostic Testing

• Chest radiograph (PA and lateral views) is essential to confirm the diagnosis before initiating treatment. 4

• Sputum Gram stain and culture are not necessary for low-risk outpatients and should not delay empiric therapy. 2, 1 The practice of using sputum Gram stain to guide initial therapy has no firm basis in published studies. 2

• Blood cultures and extensive diagnostic testing are not indicated for CURB-65 0-1 patients managed as outpatients. 2

Supportive Care

• Advise adequate hydration of at least 2-3 liters of fluid daily. 2, 4

• Recommend smoking cessation and advise patients not to smoke during illness. 2, 4

• Antipyretics such as paracetamol 500 mg 1-2 tablets every 6 hours as needed for fever management. 4

• Pleuritic pain should be relieved with simple analgesia such as paracetamol. 2

Treatment Duration

• Minimum 5 days of therapy for uncomplicated CAP with clinical response. 1 Typical total duration is 7-8 days. 1

• Patients must complete the full antibiotic course even if symptoms improve. 4

Follow-Up and Monitoring

• Clinical reassessment at 48-72 hours is mandatory to evaluate response to therapy and reassess for adverse prognostic features. 2, 4

• Return immediately if experiencing worsening shortness of breath, chest pain, confusion, or inability to maintain oral intake. 4

• Schedule follow-up visit in 7-10 days to ensure clinical resolution. 4

• Clinical review at 6 weeks with chest radiograph is indicated for patients with persistent symptoms, physical signs, or those at higher risk of underlying malignancy (especially smokers and those over 50 years). 2

Prevention

• Consider pneumococcal and influenza vaccination if not previously administered. 4, 5

Common Pitfalls to Avoid

• Do not delay antibiotic initiation while awaiting diagnostic test results in patients with clinical pneumonia. 1 For patients requiring hospital referral where delays exceed 2 hours, general practitioners should consider administering antibiotics immediately. 2

• Do not omit coverage for atypical pathogens (Legionella, Mycoplasma, Chlamydophila), as they represent a significant proportion of CAP cases. 1 This is why combination therapy or respiratory fluoroquinolones are preferred in some guidelines. 2

• Do not rely solely on clinical syndromes to predict microbial etiology, as this practice has no firm scientific foundation. 2

• Do not hospitalize low-risk patients unnecessarily. 2 Outpatient treatment allows patients to resume normal activity sooner, is preferred by 80% of patients, and costs 25 times less than inpatient care. 2