Approach to managing adults with CAP who are not improving

If the clinical features of community-acquired pneumonia (CAP) do not improve as expected with appropriate antibiotic therapy, reassess the diagnosis and seek expert advice if required. Ensure airway clearance strategies are optimised (eg chest physiotherapy). In addition, reassess the patient’s prognosis, preferences and goals of care; see Pneumonia in palliative care in the Palliative Care guidelines. For patients managed in the community, review disease severity and whether to admit the patient to hospital.

Note: If the clinical features have not improved with appropriate antibiotic therapy, reassess the diagnosis of CAP.

Complications of CAP and differential diagnoses to consider are listed in Considerations in adults with community-acquired pneumonia (CAP) who are not improving on empirical antibiotic therapy. For adults with immune compromise, consider a broader range of pathogens – see Considerations in managing CAP in adults with immune compromise. If extensive microbiological testing is required, discuss the need for bronchoscopy with a respiratory physician.

Figure 1. Considerations in adults with community-acquired pneumonia (CAP) who are not improving on empirical antibiotic therapy

Review the results of previous diagnostic tests (eg sputum samples) and disease severity. Consider the need for further clinical and microbiological investigations, including NAAT (eg PCR).

Consider complications of pneumonia – lung abscess, parapneumonic effusion and thoracic empyema should be considered in patients with persistent symptoms (eg fever, chest discomfort).

Consider noninfective diagnoses, such as:

heart failure
noninfective exacerbations of COPD
acute respiratory distress syndrome
interstitial lung diseases (eg cryptogenic organising pneumonia, hypersensitivity pneumonitis, idiopathic pulmonary fibrosis, sarcoidosis)
cancer
pulmonary embolism.

Test for an undiagnosed immune system disorder (eg HIV infection).

Investigate for a broader range of pathogens, particularly in adults with immune compromise [NB1]. These include:

viral pathogens that can cause pneumonia and pneumonitis, including influenza virus, parainfluenza virus, human metapneumovirus, coronavirus (eg SARS-CoV-2), RSV and cytomegalovirus
bacterial pathogens
- anaerobes not adequately treated with standard empirical therapy – especially in patients with severe periodontal disease or putrid sputum. See Management of aspiration pneumonia in patients who are not improving on empirical therapy for CAP or HAP for management
- atypical pathogens [NB2] (eg Legionella, Mycoplasma and Chlamydophila (Chlamydia) species) – see Directed therapy for pneumonia for management
- Burkholderia pseudomallei – can cause pneumonia in tropical regions of Australia [NB3], particularly in patients with risk factors [NB4]
- Pseudomonas aeruginosa – especially in patients withhaematological cancer, immunoglobulin deficiencies, comorbid lung disease, or recent antibiotic exposure
- multidrug-resistant gram-negative bacteria – ESBL-producing Enterobacterales and carbapenemase-producing Enterobacterales are uncommon causes of CAP; if suspected or confirmed, consult an infectious diseases physician, clinical microbiologist, or local protocols (if available). See also Enterobacterales pneumonia
- Nocardia species
mycobacterial pathogens
- Mycobacterium tuberculosis – especially in patients from high-prevalence areas with prolonged symptoms
- nontuberculous mycobacteria
fungal pathogens
Strongyloides stercoralis in patients with past or present epidemiological risk of acquiring S. stercoralis.

Note:

COPD = chronic obstructive pulmonary disease; ESBL = extended-spectrum beta-lactamase; HIV = human immunodeficiency virus; NAAT = nucleic acid amplification testing; PCR = polymerase chain reaction; RSV = respiratory syncytial virus; SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2

NB1: For further considerations, see Considerations in managing CAP in adults with immune compromise.

NB2: There is no universally accepted definition of atypical pathogens. The term is used to describe bacteria that are intrinsically resistant to beta lactams and not identifiable by standard blood or sputum culturesGarin, 2022.

NB3: Tropical regions of Australia refer to regions north of 20°S latitude. This includes areas of Queensland north of Mackay, the Northern Territory north of Tennant Creek, and Western Australia north of Port Hedland.

NB4: Risk factors for B. pseudomallei pneumonia include diabetes, chronic kidney disease, chronic respiratory disease (especially cystic fibrosis), a history of heavy alcohol consumption (including binge drinking) and immunosuppressive therapy.