How should I determine the severity of pneumonia in a patient to guide management decisions?

To determine the severity of pneumonia in a patient and guide management decisions, use a validated clinical risk score combined with clinical judgement.

In primary care or community settings, apply the CRB65 score, which assigns 1 point each for: confusion, respiratory rate ≥30 breaths/min, low blood pressure (diastolic ≤60 mmHg or systolic <90 mmHg), and age ≥65 years. Stratify risk as low (0 points), intermediate (1-2 points), or high (3-4 points). Consider hospital assessment for scores ≥2, shared decision-making for score 1, and home care for score 0, while also factoring in comorbidities, pregnancy, social circumstances, and oxygen saturation levels.

In hospital settings, use the CURB65 score, which includes the same criteria as CRB65 plus blood urea nitrogen >7 mmol/L. Risk categories are low (0-1), intermediate (2), and high (3-5). Consider home care for low risk, hospital care for intermediate risk, and intensive care assessment for high risk.

Always integrate clinical judgement with these scores, especially if the patient has features like low oxygen saturation or inability to eat, which may indicate severe illness despite a low score.