Extracorporeal Membrane Oxygenation Rescue for Severe Pneumocystis Pneumonia with the Macklin Effect: a Case Report

Background: Pneumocystis jirovecii pneumonia (PJP) in an immunocompromised host is often associated with the Macklin effect, which can progress to spontaneous pneumomediastinum (SPM), subcutaneous emphysema (SCE), and pneumothorax (PNX). Diagnosing the causative organism of these conditions in non-HIV infected patients and treating hypoxemia while preventing further lung damage can be challenging. This study examines the case of a non-HIV infected male with SPM, SCE, and PNX secondary to severe Pneumocystis jirovecii (PJ) infection.

Case Presentation: A 53-year-old male with pure red cell aplasia (PRCA) was admitted with fever, dry cough, and shortness of breath. His respiratory function progressively deteriorated due to the development of SPM, SCE, and PNX, eventually requiring endotracheal intubation and invasive ventilation. As a result of high pressure in his airways occasioned by lung recruitment maneuvers, his pulmonary parameters worsened, necessitating veno-venous (VV) extracorporeal membrane oxygenation (ECMO) therapy. The early initiation of VV-ECMO facilitated ultra-protective lung ventilation and prevented the progression of SPM, SCE, and PNX. Traditional diagnostic assays were unrevealing, whereupon the patient resorted to the metagenomic next-generation sequencing technology for uncovering potential pathogens. Consequently, we detected a significantly higher infection by PJ in the patient's bronchoscopy lavage fluid. Finally, the patient was successfully treated with appropriate antimicrobials and was decannulated after nine days of ECMO support.

Conclusions: SPM, SCE, and PNX are rare clinical manifestations of PJP. However, they can be considered as poor prognostic factors of the infection. Physicians should, therefore, be alert to the possibility of PJP in immunocompromised patients.