Medical Diagnostics & Clinical Scoring

CURB-65 Severity Score for Pneumonia

Calculate the CURB-65 score to predict 30-day mortality in community-acquired pneumonia and determine the need for inpatient admission.

CURB-65 Score
0
30-Day Mortality0.6%
RecommendationOutpatient

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Clinical Overview

The CURB-65 Score is an internationally recognized clinical prediction rule validated for predicting 30-day mortality in patients with community-acquired pneumonia (CAP). By assessing five simple parameters, it allows emergency physicians and hospitalists to objectively determine whether a patient can be safely treated as an outpatient or if they require hospitalization or intensive care.

Pathophysiology & Evidence

Community-acquired pneumonia can rapidly progress to sepsis and respiratory failure. The variables in CURB-65 capture the systemic response to severe infection:

  • Confusion: Indicates poor cerebral perfusion or systemic toxemia.
  • Urea (BUN): Elevated BUN reflects dehydration, acute kidney injury, or increased catabolism due to severe infection.
  • Respiratory Rate: Tachypnea (≥30 breaths/min) is a primary compensatory mechanism for hypoxemia and metabolic acidosis.
  • Blood Pressure: Hypotension signals impending septic shock.

Formula Breakdown

Each of the five criteria is worth 1 point:

Score = C(1) + U(1) + R(1) + B(1) + 65(1)

Where:
C=
Confusion (AMTS ≤ 8)
U=
BUN > 19 mg/dL

Mortality risk scales exponentially with the score. A score of 0-1 carries a mortality risk of <3%, whereas a score of 5 indicates a mortality risk approaching 30%.

Frequently Asked Questions

CURB-65 stands for Confusion, Urea (BUN > 19 mg/dL), Respiratory rate (≥30), Blood pressure (Systolic <90 or Diastolic ≤60), and Age ≥65.

CURB-65 is simpler to calculate at the bedside but may be less sensitive than the Pneumonia Severity Index (PSI). PSI relies on 20 variables, whereas CURB-65 only requires 5.

A score of 2 generally indicates a short inpatient stay or very close outpatient monitoring. A score of 3 or higher warrants hospital admission, and scores of 4-5 often require ICU level care.

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