スピロノラクトンが腹水を伴う右心不全に著効した肺性心の1例

A Case of Cor Pulmonale with Massive Ascites Successfully Treated with Spironolactone

要旨

　患者は48歳，女性．胸郭形成術後の肺性心を基盤とし，著明な腹水貯留を伴う右心不全増悪で当科入院．フロセミド40mg/日静注の初回投与を開始するも，体重および腹水の減少は認めなかった．第15病日にスピロノラクトン25mg/日を併用したところ，急激な尿量増加を認め，体重13kg，腹囲17cmの著明な減少が得られた．

　ループ利尿薬慢性投与による同薬耐性に対し，別排尿作働部位を有する他利尿薬併用が有効な症例はときに経験するが，同薬初回投与直後のスピロノラクトン併用による著効例は稀である．右心不全に付随する腹水の貯留機序は肝硬変でのそれに近似し，一方でスピロノラクトンは肝硬変腹水例での第一選択薬である．本例の経過は，肝硬変時と同様スピロノラクトンがレニン・アンジオテンシン・アルドステロン系抑制，直接的な肝静脈・門脈圧低下作用，および腹水からの血管内容量維持を通じて著明かつ持続的な利尿効果を発現し得たものと推定された．

Summary

　A 48-year-old woman,who underwent thoracic plastic surgery for a mediastinal tumor at 27 years of age,was hospitalized because of worsening right heart failure with massive ascites derived from cor pulmonale. The initial administration of intravenous furosemide together with enalapril was unable to improve symptoms including a decrease of body weight and ascites. The introduction of spironolactone at a dosage of 25mg/day,thereafter,dramatically increased urine volume while,at the same time, decreasing her body weight by 13kg and reducing ascites by 17cm of abdominal circumference.

　The clinical course for the effectiveness of spironolactone in this patient was uncommon,unlike the additive effect against diuretic tolerance with long-term administration of loop diuretics. It is widely known that spironolactone decreases ascites more effectively than furosemide in cirrhotic patients. Similarly in this case,the administration of spironolactone was able to induce effective long-term diuresis,presumably by modulating the renin-angiotensin-aldosterone system,directly decreasing hepatic and portal venous pressure,and keeping intravascular volume supplied from ascites. The present case indicates that spironolactone may be the most useful drug of choice for first-line management of heart failure with ascites.