Pneumonia: CURB-65 vs PSI, Antibiotics & When to Admit

Community-acquired pneumonia (CAP) care hinges on fast triage, using a severity score that fits your workflow, and starting the right empiric antibiotics—then de-escalating once data lands. Here’s a compact, clinic- and ED-ready playbook.

Presentation & Red Flags

• Cough, fever, pleuritic pain, dyspnea, sputum; in older adults: confusion, falls, or functional decline.
• Red flags: hypotension, RR ≥30, SpO₂ ≤90–92% on room air, altered mentation, multilobar findings, sepsis signs.

Initial Diagnostics

• Vitals & oxygen (target SpO₂ usually 92–96%; individualize for COPD/hypercapnia).
• Chest radiograph to confirm infiltrate; point-of-care lung ultrasound can speed detection.
• Labs as indicated: CBC, BMP, CRP; consider procalcitonin to support stewardship (don’t delay treatment if severe).
• Microbiology when higher risk/severe: blood cultures, sputum Gram/culture, and tests for MRSA/Pseudomonas risk; viral PCR (influenza/COVID-19) during respiratory virus season.

Pick a Severity Tool

• CURB-65: Confusion, Urea >7 mmol/L (BUN >19 mg/dL), RR ≥30, low BP (SBP <90 or DBP ≤60), Age ≥65. Scores 0–1: outpatient likely; 2: short stay/observation; ≥3: admit/consider ICU.
• PSI (Pneumonia Severity Index): more granular (age, comorbids, exam, labs, CXR). Great for disposition but takes longer.
• Use scores to augment clinical judgment—oxygen need, social support, and comorbidity often decide.

Disposition Logic

• Outpatient: low score, normal/near-normal vitals, SpO₂ stable on room air, reliable follow-up, no concerning comorbidity.
• Observation/Inpatient: hypoxemia, tachypnea ≥30, hypotension, sepsis, poor PO tolerance, multilobar disease, or decompensating comorbids (CHF, CKD, COPD).
• ICU indicators: shock requiring vasopressors, respiratory failure needing ventilation/high FiO₂, or severe hypoxemia with extensive consolidation.

Empiric Antibiotics (Adults, non-immunocompromised)

Tailor to local resistance patterns and allergies; de-escalate when cultures/viral tests return.

• Outpatient, no major comorbidity:
  • High-dose amoxicillin (e.g., 1 g TID) or doxycycline.
  • A macrolide alone only where pneumococcal resistance is low per local data.
• Outpatient with comorbidity (chronic heart/lung/liver/kidney disease, diabetes, alcoholism, malignancy, asplenia):
  • Amoxicillin-clavulanate plus azithromycin/clarithromycin or doxycycline,
  • or respiratory fluoroquinolone monotherapy (e.g., levofloxacin, moxifloxacin).
• Inpatient, non-ICU:
  • IV beta-lactam (e.g., ceftriaxone, ampicillin-sulbactam) plus azithromycin,
  • or respiratory fluoroquinolone monotherapy.
• ICU/severe CAP:
  • IV beta-lactam plus azithromycin or beta-lactam plus respiratory fluoroquinolone.
  • Add MRSA coverage (vancomycin or linezolid) if risk factors (post-influenza necrotizing pneumonia, prior MRSA, cavitation).
  • Consider Pseudomonas coverage (e.g., piperacillin-tazobactam, cefepime, or meropenem) if structural lung disease, prior colonization, recent broad-spectrum antibiotics, or frequent hospital exposure.
• Influenza/COVID-19 positive: add antivirals per protocol; still treat for bacterial CAP if clinically suspected.

Duration & IV→PO Switch

• Typical ≥5 days, longer if slow clinical response, MRSA/Pseudomonas, empyema, or extrapulmonary complications.
• Switch IV→PO when afebrile 24–48 h, hemodynamically stable, improving cough/dyspnea, and able to take PO.

Adjuncts & Support

• Antipyretics, hydration, pulmonary hygiene; oxygen to target saturation (avoid unnecessary hyperoxia).
• Systemic steroids are not routine in non-severe CAP; consider in refractory septic shock per critical-care protocols.

Follow-Up

• Reassess within 24–72 h (tele/clinic). Earlier if high risk or worsening symptoms.
• Consider repeat CXR at 4–6 weeks in age ≥50, smokers, or if symptoms persist to exclude hidden lesions or non-resolving pneumonia.
• Vaccination counseling: influenza, COVID-19, and pneumococcal per age/indications.

Patient FAQs

“Do I need a CT scan?” Usually not—CXR confirms most CAP. CT is for complications or unclear diagnoses.

“Why did my antibiotics change?” We start broad based on risk and narrow once tests identify the cause—this improves safety and stewardship.

References & Notes

Practical CAP approach: severity scoring (CURB-65/PSI) for disposition, targeted diagnostics, and empiric regimens adapted to local resistance with early de-escalation. Local protocols vary—follow institutional guidance. Educational only.