Pneumocystis carinii Infection in a Renal Transplant Recipient Presented as Walking Pneumonia Occurring 18 Years After Transplantation: A Case Report

Introduction Pneumocystis carinii pneumonia remains a crucial cause of morbidity and mortality in organ transplant recipients. Pneumocystis carinii pneumonia occurs most frequently within the first 6 months post-transplant. Onset is generally fulminant, and typical symptoms include fever and productive cough accompanied with respiratory distress. Case Presentation Here, we present a case of a patient who developed P. carinii pneumonia 18 years after renal transplantation and referred to Taichung Veteran General hospital in Taiwan in September 2015. The disease course was indolent without hypoxemia and dyspnea, mimicking walking pneumonia. The risk factors in our case contributing to P. carinii pneumonia included increased doses of immunosuppressants due to recent rejection, treatment with tacrolimus rather than cyclosporine, lymphopenia, and possibly the occurrence of urothelial carcinoma, implying an immune-deficient state. The inflammatory response of P. carinii pneumonia was not intense and gave rise to an indolent disease course. Conclusions This case should remind clinicians that P. carinii pneumonia could present atypically in an indolent form many years following organ transplantation, especially when predisposing factors are present. Longer duration of P. carinii pneumonia prophylaxis, especially for high-risk patients such as those with potent immunosuppressive regimen, or those who received recent treatment for acute cellular or humeral rejection may be considered.