Acute exacerbation of pulmonary toxoplasmosis during corticosteroid therapy for immune thrombocytopenia: A case report and literature review

RATIONALE: Pulmonary toxoplasmosis (PT) is an infectious disease that can be fatal if reactivation occurs in the recipients of hematopoietic stem cell transplantation (HSCT) who were previously infected with Toxoplasma gondii. However, whether the toxoplasmosis reactivation is an actual risk factor for patients receiving immunosuppressive therapies without HSCT remains unclear. Therefore, reactivated PT is not typically considered as a differential diagnosis for pneumonia other than in patients with HSCT or human immunodeficiency virus (HIV). PATIENT CONCERNS: A 77-year-old man presented with fever and nonproductive cough for several days. He was hospitalized due to atypical pneumonia that worsened immediately despite antibiotic therapy. Before 4 months, he was diagnosed with immune thrombocytopenia (ITP) and received corticosteroid therapy. Trimethoprim–sulfamethoxazole (ST) was administered to prevent pneumocystis pneumonia resulting from corticosteroid therapy. DIAGNOSIS: The serological and culture test results were negative for all pathogens except T. gondii immunoglobulin G antibody. Polymerase chain reaction, which can detect T. gondii from frozen bronchoalveolar lavage fluid, showed positive results. Therefore, he was diagnosed with PT. INTERVENTION: ST, clindamycin, and azithromycin were administered. Pyrimethamine and sulfadiazine could not be administered because his general condition significantly worsened at the time of polymerase chain reaction (PCR) examination. OUTCOMES: The patient died of acute respiratory distress syndrome despite anti-T. gondii treatment. An autopsy revealed a severe organizing pneumonia and a small area of bronchopneumonia. LESSONS: PT should be considered as a differential diagnosis in patients with pneumonia, particularly in seropositive patients who receive immunosuppressive therapies even for other than HSCT or HIV.