Pneumocystis jirovecii Pneumonia in Children with Hematological Malignancies: Diagnosis and Approaches to Management.

Elpis Mantadakis

doi:10.3390/jof6040331

Abstract

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection that mostly affects children with suppressed cellular immunity. PJP was the most common cause of infectious death in children with acute lymphoblastic leukemia prior to the inclusion of cotrimoxazole prophylaxis as part of the standard medical care in the late 1980s. Children with acute leukemia, lymphomas, and those undergoing hematopoietic stem cell transplantation, especially allogeneic transplantation, are also at high risk of PJP. Persistent lymphopenia, graft versus host disease, poor immune reconstitution, and lengthy use of corticosteroids are significant risk factors for PJP. Active infection may be due to reactivation of latent infection or recent acquisition from environmental exposure. Intense hypoxemia and impaired diffusing capacity of the lungs are hallmarks of PJP, while computerized tomography of the lungs is the diagnostic technique of choice. Immunofluorescence testing with monoclonal antibodies followed by fluorescent microscopy and polymerase chain reaction testing of respiratory specimens have emerged as the best diagnostic methods. Measurement of (1-3)-β-D-glucan in the serum has a high negative predictive value in ruling out PJP. Oral cotrimoxazole is effective for prophylaxis, but in intolerant patients, intravenous and aerosolized pentamidine, dapsone, and atovaquone are effective alternatives. Ιntravenous cotrimoxazole is the treatment of choice, but PJP has a high mortality even with appropriate therapy.

Highlights

Pneumocystis jirovecii is an important cause of pneumonitis in immunocompromised children.Carini, who isolated it from infected rats [1]
When the CT findings are unclear, fluorodeoxyglucose positron emission tomography (FDG PET) can be used to diagnose Pneumocystis jirovecii pneumonia (PJP), and it aids with monitoring response to therapy [53,54,55]
In high-risk children with leukemia, the clinical and radiological findings are usually enough for initiating empirical therapy, but every effort should be made to achieve a mycological diagnosis

Summary

Introduction

Pneumocystis jirovecii is an important cause of pneumonitis in immunocompromised children. The diagnosis of PJP has increased among non-HIV patients [10,11], among those who receive immunosuppressive therapy for hematological malignancies [12,13], solid tumors, collagen vascular diseases [14], and hematopoietic or solid organ transplantation [15]. A British study demonstrated that the laboratory-confirmed cases, deaths, and hospital admissions from PJP in England increased by an average of 7% per year from 2000 to 2010, but this surge was limited to patients with hematological malignancies or who had been transplanted [17]. Nowadays, chronic corticosteroid use is the single most important risk factor for patients without AIDS who develop PJP. Survival was significantly poorer among cases versus controls; risk factors included graft versus host disease (GVHD) and poor immune reconstitution [29]

Clinical Picture and Imaging Findings of PJP

Laboratory Diagnosis of PJP

Differential Diagnosis of PJP

Prophylaxis against PJP

Treatment of PJP

Conclusions