CURB-65 Components for Community-Acquired Pneumonia
The correct answer is A: BUN greater than 19 mg/dL is a component of the CURB-65 decision aid.
Understanding CURB-65 Components
The CURB-65 score consists of exactly five clinical parameters, each worth one point 1, 2:
- Confusion (new onset)
- Urea nitrogen (BUN >19 mg/dL or >7 mmol/L)
- Respiratory rate ≥30 breaths per minute
- Blood pressure (systolic <90 mmHg or diastolic ≤60 mmHg)
- 65 years of age or older
Why the Other Options Are Incorrect
The parameters listed in options B, C, and D are not part of CURB-65:
- Glucose >250 mg/dL is not included in CURB-65 1, 2
- Pulse >125 bpm is not a CURB-65 criterion 1, 2
- Sodium <130 mg/dL is not part of this scoring system 1, 2
These parameters may be included in other pneumonia severity tools like the Pneumonia Severity Index (PSI), which uses up to 20 variables, but they are specifically excluded from CURB-65's simplified five-variable approach 1, 2.
Clinical Application of CURB-65
The score directly correlates with 30-day mortality risk:
- Score 0-1: 0.7-2.1% mortality; consider outpatient treatment 2, 3
- Score 2: 9.2% mortality; consider short hospital stay or supervised outpatient care 2, 3
- Score 3: 14.5% mortality; hospital admission and ICU assessment 2, 3
- Score 4-5: 40-57% mortality; hospital admission and ICU assessment 2, 3
Practical Advantages
CURB-65 requires only one laboratory test (BUN/urea), making it highly practical at the point of care 1, 2. This is a significant advantage over the PSI, which requires multiple laboratory values and is more complex to calculate 1.
A simplified CRB-65 variant omits the urea measurement entirely and can be used when laboratory testing is unavailable, particularly useful in outpatient settings 1, 2, 4.
Important Clinical Caveats
CURB-65 should support, not replace, clinical judgment 1, 2. External factors must be considered:
- Comorbidities not captured by the score (e.g., HIV, immunosuppression) 1, 2
- Failure of prior outpatient antibiotic therapy 1
- Social factors affecting medication adherence or ability to obtain care 1, 2
- Young patients with severe respiratory failure may be underestimated 2
For ICU admission decisions specifically, CURB-65 performs less effectively than IDSA/ATS severe CAP criteria 2. Patients with septic shock requiring vasopressors or acute respiratory failure requiring mechanical ventilation need direct ICU admission regardless of CURB-65 score 2.