Overview
Pneumonia in the immunocompromised host is a complex infection and inflammation of the lower respiratory tract, complicated by widespread multi-drug antibiotic resistance, and aided by medical advances such as improvements in diagnostic measures and immunosuppressive agents. Though overall patient survival has increased, pneumonia is both the most common invasive infection in immunocompromised patients and continues to carry a high mortality and morbidity rate.
The major immunocompromised host groups are those with:
HIV/AIDS
Solid organ and hematopoietic cell transplants
Malignancy on chemotherapy or radiation therapy
Primary immunodeficiencies and autoimmune diseases
Acquired immunodeficiencies: asplenia, long-term steroid use
Chest radiograph of HIV-infected patient with PJP shows diffuse patchy infiltrates with predominantly perihilar and interstitial prominence, as well as a few pneumatocoeles up to 1cm in size. Courtesy of Radiopaedia (https://radiopaedia.org/), case of Dr Andrew Dixon, rID 9613.
Chest CT of HIV-infected patient with PJP shows early findings of diffuse ground glass opacities, and chronic findings of linear opacities and thickening of interlobular septa. Courtesy of Radiopaedia (https://radiopaedia.org/), case of Dr Yune Kwong, rID 26697.
Complications
Pneumonia in immunocompromised is often complicated by superinfection, drug toxicity, empyema, sepsis, pneumothorax, and acute respiratory distress syndrome (ARDS).