Management of Pneumonia in Immunocompromised Hosts

Initial Assessment and Diagnostic Approach

The Infectious Diseases Society of America recommends obtaining blood cultures, endotracheal aspirate (if intubated), and considering bronchoalveolar lavage (BAL) with biopsy when possible to identify specific pathogens in immunocompromised patients with pneumonia 1, 2
Urinary antigen tests for Legionella pneumophila and Streptococcus pneumoniae should be performed in immunocompromised patients with pneumonia 3
A CT scan of the chest and sinuses should be considered to evaluate for occult invasive fungal infection in high-risk immunocompromised patients with pneumonia 1
Pneumonia in immunocompromised patients should be treated as healthcare-associated pneumonia even when community-acquired 1

The American College of Clinical Pharmacy recommends an antipseudomonal β-lactam (such as ceftazidime, cefepime, or piperacillin-tazobactam) plus either azithromycin or a respiratory fluoroquinolone as empiric therapy for hospitalized immunocompromised patients with pneumonia 2, 3
For severe pneumonia, vancomycin or linezolid should be added for MRSA coverage, and an aminoglycoside (such as amikacin) should be considered for double coverage against Pseudomonas in critically ill patients 1, 2, 4

Immunocompromised patients have a higher risk for Streptococcus pneumoniae, Pseudomonas aeruginosa, respiratory syncytial virus, Pneumocystis jirovecii, Aspergillus fumigatus, and Nocardia species 6, 7
Bacterial co-infection is common with viral pneumonias, particularly influenza, which can lead to secondary infection with S. pneumoniae, S. aureus, or H. influenzae 7

The Infectious Diseases Society of America recommends continuing appropriate antibiotics for at least the duration of neutropenia (until ANC > 500 cells/mm³) in immunocompromised patients with pneumonia 1, 2
For documented infections, the duration of therapy should be appropriate for eradication of the identified pathogen 2
For Nocardia pneumonia, prolonged therapy of 6-24 months is recommended based on disease severity and immunosuppression status 5

Therapy should be de-escalated based on culture results and clinical response in immunocompromised patients with pneumonia 4, 3
For patients who remain neutropenic after completing an appropriate treatment course with resolution of symptoms, oral fluoroquinolone prophylaxis should be considered until marrow recovery 2

The American Thoracic Society recommends avoiding underestimation of the potential for opportunistic and resistant pathogens in immunocompromised hosts with pneumonia 7, 1
Prior antibiotic use increases the risk of resistant organisms, particularly for Pneumococcus, in immunocompromised patients with pneumonia 7
Inadequate or limited initial regimens for healthcare-associated pneumonia are major risk factors for excess mortality and prolonged hospital stays in immunocompromised patients 1