誘発試験により診断した超音波加湿器による急性過敏性肺炎の1例

A Case of Hypersensitive Pneumonitis Associated with Ultrasonic Humidifier

要旨　症例は34歳，女性．来院1カ月前から咳嗽と発熱が出現し当科受診となり胸部CTにて両側肺野にびまん性にすりガラス状陰影を認めた．市中肺炎と判断し抗菌薬による治療にて軽快し入院10日後に退院した．退院翌日より咳嗽，発熱が出現し再入院となった．再度の病歴聴取により加湿器による急性過敏性肺炎を疑い，診断目的に病室にて加湿器による誘発試験を施行したところ陽性であった．入院後は抗原回避目的の経過観察のみで軽快した．加湿器による過敏性肺炎と診断し以後自宅での加湿器の使用を中止し再燃を認めていない．

　A 34-year-old woman was admitted with fever and cough. Her chest radiograph and CT scan showed ground glass opacity in both lungs. She was treated with ceftriaxone and minocycline for community-acquired pneumonia. After receiving antibiotic therapy on admission, these shadows disappeared and her general condition improved. She was thus discharged from our hospital. However, after discharge, she experienced productive cough and fever and had to be admitted again. Later, we found that she was continuing to use the humidifier in her home. Thus, we suspected hypersensitive pneumonitis associated with the use of ultrasonic humidifier. An inhalation test using her humidifier provoked fever and cough, and laboratory tests showed elevation in the levels of C-reactive protein and number of white blood cells. Therefore, this patient was diagnosed with humidifier lung. After the second discharge to her home, she did not use the humidifier, and did not develop cough and fever.