Considerations in managing CAP in adults with immune compromise
Adults with immune compromise are at greater risk of pneumonia than adults without immune compromise.
Although a broad range of pathogens can cause community-acquired pneumonia (CAP) in adults with immune compromise, the most common pathogens are the same as in adults without immune compromise (eg Streptococcus pneumoniae) – see Aetiology of community-acquired pneumonia (CAP) in adults.
For adults with immune compromise who have CAP, use the standard empirical antibiotic therapy; see Low-severity CAP in adults, Moderate-severity CAP in adults or High-severity CAP in adults.
Adults with CAP who have one of the immunocompromising factors listed in Immunocompromising factors that increase the risk of a broader range of pathogens in adults with community-acquired pneumonia (CAP) are predisposed to a broader range of pathogens. Consider early referral to a respiratory physician to discuss the utility of bronchoscopy (eg bronchoalveolar lavage [BAL]) to obtain samples for extensive microbiological testing; the patient’s respiratory function and need for intubation influence the timing of bronchoscopy. Seek advice from an infectious diseases physician or microbiologist on whether to adjust empirical antibiotic therapy for CAP while awaiting the results of investigations.
[NB1]Ramirez, 2020
- primary immune deficiency diseases
- solid organ or haematopoietic stem cell transplant
- cancer that suppresses immune responses (eg lymphoma, leukaemia)
- HIV infection with a CD4 cell count less than 200 cells/microlitre
- chemotherapy that causes neutropenia
- high-dose corticosteroid therapy (ie prednisolone 20 mg or more daily for at least 2 weeks, or a cumulative prednisolone dose of 600 mg or more [NB1])
- biological therapies used to treat rheumatological, dermatological, gastrointestinal and autoimmune diseases
- conventional synthetic disease-modifying antirheumatic drugs or other immunosuppressive drugs (eg azathioprine, cyclosporin, methotrexate).
HIV = human immunodeficiency virus
NB1: For corticosteroid doses approximately equivalent to prednisolone 20 mg daily, see Corticosteroid doses approximately equivalent to prednisolone 20 mg daily
Pathogens to consider in patients with CAP who have a factor listed in Immunocompromising factors that increase the risk of a broader range of pathogens in adults with community-acquired pneumonia (CAP) include:
- viral pathogens that can cause pneumonia and pneumonitis (eg cytomegalovirus [CMV], herpes simplex, herpes zoster, varicella zoster) – although reactivation is common in adults with CAP, it is less common for these viruses to be the cause of CAP (except in patients undergoing treatment for haematological cancer)
- bacterial pathogens
- Burkholderia pseudomallei – can cause pneumonia in tropical regions of Australia1, particularly in patients with risk factors2
- gram-negative bacteria, including Pseudomonas aeruginosa – especially in patients with haematological cancer or immunoglobulin deficiencies. See Directed therapy for pneumonia for management
- Mycobacterium tuberculosis – especially in patients from high-prevalence areas with prolonged symptoms
- Nocardia species – usually cause focal lung infections
- fungal pathogens
- Aspergillus species – can cause invasive aspergillosis in patients with significant immunosuppression (eg neutropenia after intensive chemotherapy)
- Cryptococcus species – usually cause focal lung infections
- Pneumocystis jirovecii.
- Strongyloides stercoralis – in adults with past or present epidemiological risk of acquiring S. stercoralis.