A Rare Case of Severe Hemolytic Anemia and Pulmonary Embolism Secondary to Mycoplasma pneumoniae Infection.

A 27-year-old woman was admitted with a history of dry cough, breathlessness, fever, lethargy, and nausea and vomiting. On examination, she was febrile, jaundiced, and hypoxic. Blood tests revealed severe leucocytosis and severe hemolytic anemia. The chest imaging demonstrated coexisting pneumonia and pulmonary embolism. An initial blood transfusion worsened the hemolytic anemia to the point that critical care review was required. Subsequent blood tests revealed cold agglutinin hemolytic anemia due to Mycoplasma pneumoniae infection. The patient's condition improved after receiving a warm-blood transfusion, antibiotics, and steroid therapy. The patient also received anticoagulant therapy for 6 months. Our case is unique in that the patient had very severe anemia and very severe leucocytosis, making us suspect a hematologic malignancy at initial presentation. This case emphasizes the importance of prompt evaluation of hemolytic anemia and the use of warm blood transfusion for cold agglutinin disease.