Pneumonia Severity Scores and CURB-65
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Direct answer
Pneumonia severity scores such as CURB-65 and the Pneumonia Severity Index estimate mortality and guide where community-acquired pneumonia is treated. CURB-65 scores confusion, urea above 7 mmol/L, respiratory rate of 30 or more, low blood pressure and age 65 or older, with a score of 2 or more prompting hospital assessment. ICU referral is guided separately by the ATS-IDSA criteria, using one major criterion or three or more minor criteria.
What you must remember
- CURB-65 components: confusion, urea above 7 mmol/L, respiratory rate of 30 or more, systolic pressure below 90 or diastolic 60 or less, and age 65 or older; each scores one point.
- CURB-65 action: a score of 0 or 1 suggests home treatment, 2 suggests short hospital assessment, and 3 or more indicates hospital admission, with ICU consideration at 4 or 5.
- CRB-65: the urea-free version used in primary care or at home where blood tests are unavailable.
- Pneumonia Severity Index: a weighted score of twenty variables including age, nursing home residence, comorbidities, abnormal vital signs and laboratory values, placed into classes I to V; classes I and II are managed as outpatients, and IV and V need admission.
- ATS-IDSA major criteria: septic shock needing vasopressors and need for invasive mechanical ventilation.
- ATS-IDSA minor criteria: respiratory rate of 30 or more, PaO2/FiO2 ratio of 250 or less, multilobar infiltrates, confusion, uraemia, leukopenia, thrombocytopenia, hypothermia and hypotension needing aggressive fluids.
A 72-year-old with confusion and a blood pressure of 88/54
A 72-year-old man presents with fever, breathlessness and new confusion. His respiratory rate is 32, blood pressure 88/54 mmHg, and urea is 9 mmol/L.
- Score with CURB-65: CURB-65 scores five, because confusion, urea, respiratory rate, blood pressure and age each contribute one point. This places him in the highest mortality band and prompts ICU consideration.
- Apply ATS-IDSA minor criteria: Respiratory rate of 30 or more, confusion, uraemia and hypotension needing fluid resuscitation together make four minor criteria, which meets ICU referral.
- Start antibiotics promptly: Antibiotics are started promptly, ideally within an hour in severe community-acquired pneumonia, after blood cultures, and oxygen is titrated to saturation.
- Measure and resuscitate: A lactate is measured and fluids are given.
- Decide with the senior team: The decision on ICU admission is made by the senior team rather than by the score alone. The Pneumonia Severity Index would also place him in the highest class, reinforcing the decision.
- Weigh the whole patient: Scores inform the decision but do not replace clinical judgement, frailty, social circumstances and oxygen requirement.
Where the examiner tests the scores
The same few confusions come up in pneumonia scoring vivas.
- Trap: mixing up CURB-65 and CRB-65 Correct: CURB-65 uses urea, which needs a blood test, while CRB-65 omits it for primary care, and creatinine is not used in place of urea.
- Trap: treating age 65 as an automatic indication for admission Correct: age alone scores one point, and a patient with a total score of 1 can still be managed at home.
- Trap: using the Pneumonia Severity Index as the bedside tool Correct: it is more detailed but slower to calculate at the bedside, so CURB-65 is the practical tool in most emergency rooms.
- Trap: using CURB-65 to decide ICU admission Correct: CURB-65 predicts mortality, while the ICU criteria predict need for organ support.
Frequently asked questions
What are the components of CURB-65?
CURB-65 scores confusion, urea above 7 mmol/L, respiratory rate of 30 or more, systolic blood pressure below 90 or diastolic 60 or less, and age 65 or older. Each feature scores one point, giving a total between zero and five.
What does a CURB-65 score of 2 mean?
A CURB-65 score of 2 in community-acquired pneumonia indicates moderate severity and suggests short-term hospital assessment rather than immediate home treatment. Clinical review and social circumstances then decide on admission.
How does CRB-65 differ from CURB-65?
CRB-65 drops the urea criterion, so it can be used in primary care or at home where blood tests are not available. Its scoring of confusion, respiratory rate, blood pressure and age is otherwise identical.
What are the ATS-IDSA criteria for ICU admission in pneumonia?
ICU admission is recommended with one major criterion, which is septic shock needing vasopressors or the need for invasive mechanical ventilation, or with three or more minor criteria. Minor criteria include respiratory rate of 30 or more and a PaO2/FiO2 ratio of 250 or less.