Investigations for CAP in children 2 months or older
Clinical features of community-acquired pneumonia (CAP) in children 2 months or older do not reliably distinguish between viral and bacterial pathogensBenet, 2017Kohns Vasconcelos, 2023. CAP in children 2 months or older is most commonly caused by viruses. Acute viral bronchiolitis is the most likely diagnosis in children 12 months or younger who present with cough, wheeze and respiratory distress – see Acute bronchiolitis.
Consider a chest X-ray to confirm the diagnosis of CAP in children 2 months or olderGeanacopoulos, 2022. Children who have widespread pulmonary wheeze or crackles but no focal changes on chest X-ray are more likely to have a viral aetiologyShah, 2024. Consider performing nucleic acid amplification testing (NAAT) (eg polymerase chain reaction [PCR]) to detect respiratory pathogens. For children with high-severity CAP, take blood samples for culture.
Identification of the pathogen can be difficult in children with CAP because children rarely produce sputum and some microbiological tests are unreliable in childrenSmyrnaios, 2023. The pneumococcal urinary antigen assay has limited use in children because nasal carriage of Streptococcus pneumoniae can lead to false-positive results. Investigations for pneumonia suspected to be caused by atypical pathogens1 (eg Mycoplasma pneumoniae) are not routinely recommended; positive NAAT (eg PCR) results can represent nasal carriage, and serological testing is rarely helpful in the acute management of CAP.