Severe Pneumocystis jirovecii Pneumonia That Was Difficult to Diagnose due to Complications of Postoperative Candida Sepsis in an Elderly Patient with Ulcerative Colitis: A Case Report.

Introduction: Pneumonia is a leading cause of postoperative mortality in elderly patients with ulcerative colitis (UC), and close attention should be paid to the possibility of Pneumocystis jiroveci pneumonia (PJP) in patients with immunosuppression. We present the case of a patient with severe PJP that was challenging to diagnose because of postoperative Candida sepsis complications in an elderly patient with acute severe ulcerative colitis (ASUC) with immunosuppression. Case Presentation: A 70-year-old man was transferred to our hospital and was diagnosed with ASUC. The patient underwent laparoscopic subtotal colectomy for prednisolone and granulocyte and monocyte adsorptive apheresis-resistance UC 22 days after transfer. On postoperative day (POD) 9, the central venous catheter (CVC) was removed because CVC-related blood stream infection (CRBSI) was suspected. On POD 12, fluconazole was administered for Candida parapsilosis sepsis due to CRBSI, and a septic pulmonary embolism was suspected. The patient's hypoxemia worsened; trimethoprim-sulfamethoxazole was administered because PJP was suspected on POD 19; however, ventilatory support was started on POD 21. PJP was diagnosed based on bronchoalveolar lavage on POD 25, and high-dose prednisolone therapy was initiated. The patient was weaned off the ventilator on POD 27 and was discharged home on POD 54. Proctectomy and stapled ileal pouch-anal anastomosis were performed at 10 months postoperatively, and the patient is currently alive at 1 year and 6 months after surgery. Conclusion: Postoperative hypoxemia in elderly patients with ASUC should be considered in the differential diagnosis of PJP, even during the treatment of Candida sepsis.