What is the treatment approach for pneumonia based on the Confusion, Uremia, Respiratory rate, and Blood pressure (CURB) score?

Pneumonia Treatment According to CURB-65 Score

Use CURB-65 to stratify pneumonia severity and guide site-of-care decisions: patients with scores 0-1 can be treated as outpatients with oral antibiotics, scores of 2 require hospitalization or intensive home care, and scores ≥3 mandate hospital admission with ICU assessment. 1, 2

Understanding CURB-65 Components

CURB-65 assigns one point for each of the following criteria 1, 2:

• Confusion (new onset)
• Urea >19 mg/dL (or BUN >7 mmol/L)
• Respiratory rate ≥30 breaths/min
• Blood pressure: systolic <90 mmHg or diastolic ≤60 mmHg
• Age ≥65 years

The simplified CRB-65 omits urea testing and can be used in outpatient settings where laboratory testing is unavailable 2, 3.

Risk Stratification and Mortality

The mortality risk increases directly with score 1, 2, 3:

• Score 0: 0.7% mortality
• Score 1: 2.1% mortality
• Score 2: 9.2% mortality
• Score 3: 14.5% mortality
• Score 4: 40% mortality
• Score 5: 57% mortality

Treatment Approach by CURB-65 Score

CURB-65 Score 0-1: Outpatient Treatment

For healthy adults without comorbidities 1:

• Amoxicillin 1 g three times daily (preferred, strong recommendation) 1
• Doxycycline 100 mg twice daily (alternative) 1
• Macrolide (azithromycin 500 mg day 1, then 250 mg daily OR clarithromycin 500 mg twice daily) only if local pneumococcal macrolide resistance is <25% 1

For adults with comorbidities (chronic heart/lung/liver/renal disease, diabetes, alcoholism, malignancy, asplenia) 1:

• Combination therapy: Amoxicillin/clavulanate (875 mg/125 mg twice daily OR 2000 mg/125 mg twice daily) OR cephalosporin (cefpodoxime 200 mg twice daily OR cefuroxime 500 mg twice daily) PLUS macrolide (azithromycin or clarithromycin) 1
• Alternative: β-lactam/β-lactamase inhibitor plus doxycycline 100 mg twice daily 1

Treatment duration: 5 days if afebrile for 48 hours and clinically stable (temperature ≤37.8°C, heart rate ≤100/min, respiratory rate ≤24/min, systolic BP ≥90 mmHg, oxygen saturation ≥90%) 1

CURB-65 Score 2: Hospitalization or Intensive Home Care

Patients with a score of 2 face 9.2% mortality and require more intensive treatment—hospitalization or intensive in-home health services where available. 1, 2

Inpatient non-ICU treatment 1:

• β-lactam-based combination: Amoxicillin/clavulanate 1.2 g IV q8h OR ampicillin/sulbactam 1.5-3 g IV q6h OR ceftriaxone 2 g IV daily OR cefotaxime 1-2 g IV q8h 1
• PLUS macrolide: Clarithromycin 500 mg IV/PO q12h OR azithromycin 500 mg PO daily 1
• OR fluoroquinolone monotherapy: Moxifloxacin 400 mg IV daily OR levofloxacin 500-750 mg IV daily 1

Treatment duration: 7 days for most cases 1

CURB-65 Score ≥3: Hospital Admission with ICU Assessment

Patients with scores of 3-5 have mortality rates of 14.5-57% and require hospital admission with prompt evaluation for ICU care. 1, 2

Direct ICU admission is mandatory for 1, 2:

• Septic shock requiring vasopressors
• Acute respiratory failure requiring intubation and mechanical ventilation

ICU admission or high-level monitoring is recommended for patients meeting ≥3 minor criteria 1, 2:

• Respiratory rate ≥30/min
• PaO₂/FiO₂ ratio ≤250
• Multilobar infiltrates
• Confusion/disorientation
• Uremia (BUN ≥20 mg/dL)
• Leukopenia (WBC <4,000 cells/mm³)
• Thrombocytopenia (platelets <100,000/mm³)
• Hypothermia (core temperature <36°C)
• Hypotension requiring aggressive fluid resuscitation

ICU treatment regimens 1:

• β-lactam: Ceftriaxone 2 g IV daily OR cefotaxime 1-2 g IV q8h OR ampicillin/sulbactam 1.5-3 g IV q6h 1
• PLUS macrolide or fluoroquinolone: Azithromycin 500 mg PO daily OR levofloxacin 500-750 mg IV daily OR moxifloxacin 400 mg IV daily 1

For Pseudomonas risk (recent hospitalization, frequent antibiotics, severe COPD with FEV1 <30%, oral steroids >10 mg prednisone daily) 1:

• Piperacillin/tazobactam 4.5 g IV q6-8h OR cefepime 2 g IV q8h OR meropenem 1 g IV q8h 1
• PLUS ciprofloxacin 400 mg IV q8-12h OR levofloxacin 750 mg IV daily 1

For MRSA risk 1:

• Add vancomycin 15-20 mg/kg IV q8-12h OR linezolid 600 mg IV q12h 1

Critical Pitfalls and Limitations

CURB-65 may underestimate severity in young patients (<65 years) with severe respiratory failure who lack age points despite significant physiologic derangement. 1, 2 In a study of 2,322 patients, 6.4% with CURB-65 scores 0-1 still required critical care interventions 4.

CURB-65 performs poorly for predicting ICU needs, with only 78.4% sensitivity for critical care interventions. 2, 4 For ICU triage decisions, use the IDSA/ATS severe CAP criteria instead 1, 2.

Consider hospitalization despite low scores for 1:

• Hypoxemia (oxygen saturation <90% or PaO₂ <60 mmHg)
• Inability to maintain oral intake or take medications
• Exacerbation of underlying diseases (COPD, heart failure, diabetes)
• Social factors (homelessness, psychiatric illness, no caregiver available)
• Pleural effusion requiring drainage
• Failed outpatient antibiotic therapy

Elderly patients with multiple stable comorbidities may have falsely elevated CURB-65 scores without true severity requiring ICU care. 2 Clinical judgment remains essential alongside the score 1, 2.

Monitoring and Follow-Up

Clinical improvement should be expected within 3 days; patients should contact their physician if no improvement occurs. 2 Reassess for treatment failure, resistant organisms, or complications if fever persists beyond 72 hours 1.