Hemorrhagic Pneumonia due to Stenotrophomonas maltophilia in a Patient with Systemic Lupus Erythematosus-associated Thrombotic Microangiopathy under Immunosuppressive Therapy.

A 61-year-old woman with systemic lupus erythematosus was admitted with persistent pericardial effusion. Blood tests suggested thrombotic microangiopathy (TMA). Treatment with methylprednisolone, fresh-frozen plasma, and rituximab was initiated after tacrolimus discontinuation. A renal biopsy revealed endothelial injury and glomerular capillary thrombi, consistent with TMA. The patient developed severe anemia and bilateral lung opacities. Bronchoalveolar lavage revealed alveolar hemorrhaging and Stenotrophomonas maltophilia, indicating hemorrhagic pneumonia. Although chest radiography showed improvement with minocycline and levofloxacin treatment, she ultimately succumbed to Candida albicans sepsis. Hemorrhagic pneumonia-causing pathogens, such as S. maltophilia, should be considered when alveolar hemorrhaging occurs during immunosuppressive therapy.