28th July 2023

Assessment and diagnosis

Severity is assessed using the CURB-65 score, with 1 point given for each of the following:

• C = confusion
• U = urea > 7 mmol/L
• R = RR ≥ 30/min
• B = BP < 90 mmHg or ≤ 60 mmHg
• 65 = age more than 65

0-1 = outpatient management, 2 = admission, 3+ = admission and consider ITU escalation.

Investigations include routine bloods such as FBC, U&Es, LTT, and CRP; blood cultures; sputum cultures, throat swab for respiratory viruses; urinary antigens; chest x-ray.

Diagnosis is made on the basis of characteristic clinical features with evidence of consolidation in the lung (i.e. auscultation findings of ‘crackles’ or radiological confirmation on chest x-ray.

The most common pathogen causing respiratory illness is Streptococcus pneumoniae. Other common causes of community acquired infection include Haemophilus influenzae and Moraxella catarrhalis, which are particularly associated with patients with COPD.

Different pathogens are implicated in different age groups, particularly paediatric respiratory tract infections, which are associated with numerous causative organisms that rarely affect adults. Children often present with upper respiratory tract infection, caused by either viruses or bacteria. This is not the focus of this topic, but a comprehensive summary can be found in the References section.