Organizing Pneumonia With Diffuse Alveolar Hemorrhage Induced by the Kampo Medicine Choreito.

Kampo medicine, a traditional Japanese herbal medicine, is covered by the Japanese National Health Insurance and prescribed for various purposes. While relatively safe with few adverse effects, it may potentially cause severe adverse effects, such as lung injury. Herein, we describe the case of a 61-year-old Japanese woman with choreito-induced lung injury that manifested as organizing pneumonia (OP) with diffuse alveolar hemorrhage (DAH). She was referred to our department due to multiple abnormal opacities detected on annual chest radiography. Chest computed tomography (CT) revealed multiple nodules in bilateral lungs. Bloody bronchoalveolar lavage fluid was obtained from the left lingular lobe, appearing nearly normal, while a transbronchial lung biopsy from a subpleural nodule in the left lower lobe was pathologically consistent with OP. The drug lymphocyte stimulation test result was positive for choreito, which the patient had regularly consumed for 6 - 7 months to treat hematuria. Consequently, a diagnosis of choreito-induced OP and DAH was made. Owing to the discontinuation of choreito alone and without the introduction of systemic steroid therapy, the multiple nodules shrank and eventually disappeared on follow-up chest CT. Regardless of the type of crude drug used in Kampo medicine, clinicians must always be careful for potential lung injury, which may present as OP with DAH.