What are the key clinical features to consider when diagnosing community-acquired pneumonia in adults?

When diagnosing community-acquired pneumonia (CAP) in adults, key clinical features to consider include symptoms and signs of a lower respiratory tract infection ¹. These typically involve an acute illness, usually with cough as the main symptom, and at least one other lower respiratory tract symptom such as fever, sputum production, breathlessness, wheeze, or chest discomfort or pain ¹. The presence of focal chest signs may also indicate CAP ¹.

For risk assessment, which informs diagnostic and management decisions in primary care, the CRB65 scoring system uses specific clinical features ¹,³. These include confusion (Abbreviated Mental Test score 8 or less, or new disorientation), a raised respiratory rate (30 breaths per minute or more), and low blood pressure (systolic less than 90 mmHg or diastolic 60 mmHg or less) ¹,³. Age 65 years or more is also a component of the CRB65 score ¹,³.

Other important clinical indicators to consider during assessment, particularly for severity, include a temperature higher than 37.5°C, a respiratory rate of 24 breaths per minute or more, a heart rate over 100 beats per minute, a systolic blood pressure of 90 mmHg or less, and oxygen saturation under 90% on room air ¹. Abnormal mental status and inability to eat without assistance are also relevant findings ¹. Pulse oximetry should be considered as part of the assessment ².