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H . influenzae , although less common ,
is an important organism frequently associated
with pneumonia in patients with COPD , due to its propensity to persistently colonise the nasopharynx and airways of
16 , 17 patients with structural lung disease .
Diagnosis
Community diagnosis of CAP continues to rely on the recognition of characteristic symptoms by primary care providers .
Although the definition of CAP includes the demonstration of consolidation on chest radiography , this can be impractical and costly in primary care , and current British Thoracic Society guidelines recommend a chest radiograph be reserved for cases of diagnostic uncertainty or not responding to treatment in the community . 18 Use of biomarkers , such as CRP , may improve diagnostic accuracy in CAP , but may be underestimated in atypical pneumonia and may not reliably discriminate between viral and bacterial aetiology . 19 , 20 Patients with symptoms of aspiration warrant assessment for chemical aspiration pneumonitis , which does not always necessitate antibiotic therapy . All patients should be assessed at initial review for the degree of pneumonia
severity , using a validated objective score such as the CRB65 ( see online resources ) or the pneumonia severity index , and triaged accordingly to community ( low severity ) or hospital-based management ( medium or high severity ). 21
Routine urinary antigen testing for S . pneumoniae and legionella , or serological screening for atypical organisms such as mycoplasma , are not required in the primary care setting and rarely
All patients should be assessed at initial review for the degree of pneumonia severity , using a validated objective score .
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change management . If a patient has a productive cough and is able to provide a sputum microscopy and culture sample prior to antibiotic commencement , this can be sought to provide antibiotic guidance and allow for de-escalation . If a patient has coryzal symptoms or presents during seasons when respiratory viruses are endemic , consider a nasopharyngeal respiratory viral PCR test for common viruses including SARS-CoV-2 , particularly if the patient is a potential candidate for targeted influenza or COVID-19 antiviral treatment .
Treatment
The recommended treatment of lowseverity CAP , being managed in the community , is shown in box 1 . 22
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Penicillin-resistant S . pneumoniae is uncommon in Australia . Organisms with in vitro resistance to penicillin combined with doxycycline or macrolide therapy are only isolated in 5.4 % of patients presenting to Australian EDs with CAP . 9 High-dose amoxicillin ( 1g rather than 500mg ) increases the likelihood of overcoming intermediate penicillin-susceptible pneumococcal strains . Broader spectrum antibiotics , such as amoxicillin-clavulanic acid and fluoroquinolones , are associated with higher rates of adverse reactions and are a key driver of antibiotic resistance . Patients with non-severe penicillin hypersensitivity should be prescribed oral cefuroxime 500mg bd in place of amoxicillin . Those with severe penicillin hypersensitivity or anaphylaxis should be prescribed single-agent oral moxifloxacin 400mg daily . The recommended duration of treatment is 5-7 days total , guided by treatment response .
Failure to respond to empiric antibiotic therapy should prompt a reassessment of the diagnosis , consideration of possible resistant organisms , as well as screening for various complications of pneumonia such as pulmonary abscess or parapneumonic effusion , which may require in-hospital workup or treatment . 23 Current guidelines do not recommend routine corticosteroid use in low-severity CAP , unless there is evidence of a concurrent exacerbation of underlying COPD . 24
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Conclusion
Bacterial CAP continues to be an important condition that affects many Australians each year , with S . pneumoniae remaining the foremost bacterial pathogen . Prompt diagnosis and triaging of patients into low , moderate and high severity determines whether a patient can be safely managed in the community . Narrow-spectrum betalactam antibiotics in combination with doxycycline is the recommended treatment for low-severity CAP , except in those with penicillin hypersensitivity . Antibiotic stewardship , especially in the management of CAP in the community , continues to be crucial in reducing the burden and emergence of resistant organisms .
References on request from kate . kelso @ adg . com . au
Box 1 : Recommended treatment for low-severity community acquired pneumonia
• Amoxicillin 1g tds orally AND
• Doxycycline 100mg bd orally
Online resources
UK National Institute for Health and Care Excellence — Pneumonia in adults : diagnosis and management nice . org . uk / guidance / cg191
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Bacterial community acquired pneumonia continues to be an important condition that affects many Australians each year . |