CURB-65 Score for Pneumonia Severity

This tool does not replace clinician judgment in determining disposition for patients with CAP; it has not been validated for and is not intended to guide specific therapeutic or pharmacologic decisions.

According to the 2019 ATS/IDSA guidelines, outpatient management is recommended for patients with a low score (0–1): 

• For healthy adults without comorbidities or risk factors for antibiotic-resistant pathogens, empiric antibiotic therapy includes one of the following: 
  
  • Amoxicillin.
  • Doxycycline. 
  • Macrolide (only in areas where pneumococcal resistance to macrolides is <25%). 
• For outpatients with comorbidities (e.g., chronic heart, lung, liver, or renal disease, diabetes, alcohol use disorder, malignancy, asplenia), the recommended treatment is either: 
  
  • Combination therapy with amoxicillin/clavulanate or a cephalosporin plus a macrolide or doxycycline.
  • Monotherapy with a respiratory fluoroquinolone.
• Clinicians should routinely consult their local institutional or regional antibiograms to guide therapy, as many practice settings have high baseline rates of macrolide resistance. 

For inpatient management of patients with a moderate to high score (≥2):

• Routine diagnostic testing (e.g., blood cultures, sputum cultures, pneumococcal urine antigen testing) is not recommended for nonsevere cases unless specific risk factors for methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa are present. 
• Patients classified as having severe CAP should undergo expanded diagnostic testing, including: 
  
  • Blood cultures.
  • Sputum cultures or molecular diagnostics.
  • Urinary antigen tests for Legionella and Streptococcus pneumoniae.
  • Viral testing for influenza or COVID-19, if circulating in the community.
• Empiric antibiotic regimens for nonsevere inpatients include either: 
  
  • Combination therapy with a beta-lactam plus atypical coverage (e.g., macrolide, doxycycline). 
  • Monotherapy with a respiratory fluoroquinolone. 
• Severe inpatient cases require combination therapy, such as a beta-lactam plus atypical coverage or a beta-lactam plus a respiratory fluoroquinolone, with targeted coverage if MRSA or P. aeruginosa risk factors are present. 
• Antibiotic therapy should continue for no less than 5 days and until the patient achieves clinical stability, including: 
  
  • Temperature ≤38°C.
  • Heart rate ≤100 beats/min.
  • Respiratory rate ≤24 breaths/min.
  • Systolic blood pressure ≥90 mmHg.
  • Arterial oxygen saturation ≥90% on room air.
  • Return to baseline mental status.

• Clinicians should maintain a low threshold to override low calculated scores in the presence of: 
  
  • Hypoxemia.
  • Significant respiratory distress.
  • Multilobar radiographic involvement.
  • Lack of reliable outpatient social support. 
• For patients in the moderate-to-high risk tiers (scores ≥2), clinicians should actively evaluate for Systemic Inflammatory Response Syndrome (SIRS) Criteria and early organ dysfunction and initiate a formal sepsis workup and evidence-based resuscitation bundle (e.g., serum lactate, blood cultures, timely intravenous antimicrobials) when clinically indicated.