レジオネラ肺炎11例の臨床像の検討：呼吸困難を訴えない急性呼吸不全は早期診断の指標となる？

A Retrospective Analysis of Clinical Profiles of Eleven Legionella Pneumonias.:Would Acute Respiratory Failure without Dyspnea be a Good Indicator for Early Diagnosis of Legionella Pneumonia?

要旨

　レジオネラ肺炎は，早期に適切な加療を開始しなければ致死率が10%前後と高い疾患である．レジオネラ肺炎の早期診断のための臨床的指標を得ることを目的に，2006〜2013年に当院で経験したレジオネラ肺炎11症例の臨床像をretrospectiveに検討した．入院時の発熱と血清CRP値の上昇が11/11例，20回/分以上の頻呼吸が10/11例に認められた．低酸素血症(SpO₂≦90%)の症例が5例あり，この5例はいずれも頻呼吸を認めていたが呼吸苦は訴えていなかった．意識障害はJapan Coma Scale(JCS)-Ⅰが8/11例，JCS-0が3/11例であった．呼吸不全にもかかわらず呼吸苦を訴えなかった5例のなかで，4例はJCS-Ⅰであった．発熱を伴う肺炎で頻呼吸や低酸素血症にもかかわらず軽度の意識障害で呼吸苦を訴えないことが，レジオネラ肺炎の早期の特徴であろう．市中肺炎群を対象に，前向き試験によるこの仮説の検証が必要である．

　Legionella pneumonia is a disease with mortality rate of approximately 10% if not treated appropriately in the early phase. In order to find the clinical indicators for early diagnosis of Legionella pneumonia, a retrospective investigation was performed on clinical profiles of eleven Legionella pneumonia patients hospitalized in Itami City Hospital during the period of 2008-2013.

　Fever and elevated acute inflammatory biomarkers were seen in all patients. Tachypnea(＞20/min)was seen in ten of eleven patients. Disturbance of consciousness of Japan Coma scale(JCS)-Ⅰ was seen in eight of the eleven patients, and four of the five hypoxemic patients(SpO₂≦90%).

　No one complained of dyspnea.

　Early phase of Legionella pneumonia would be suggested by no complaint of dyspnea in febrile patients with hypoxemia. It is necessary to investigate testing this hypothesis in a prospective comparative study among early phase of community acquired pneumonia(CAP)patients.