くも膜下出血で発症し，原発性アルドステロン症を認めた多発脳動脈瘤の1例

A Case of Ruptured Multiple Cerebral Aneurysms Associated with Primary Aldosteronism

Ⅰ．はじめに

　原発性アルドステロン症（primary aldosteronism：PA）は，副腎皮質球状層における原発性病変によりアルドステロンの過剰分泌を来す結果，二次性高血圧，低カリウム血症を呈する疾患である．近年の報告では全高血圧患者の5～10％程度を占め，従来考えられてきたよりもかなり高頻度に存在することが明らかにされている¹³⁾．PAに伴う高血圧は本態性高血圧や他の原因による二次性高血圧に比べて臓器障害は少なく予後のよい高血圧と考えられてきたが，最近，比較的軽度な高血圧でも脳血管障害の合併が多いことが報告され，注目を集めている^4,10)．TakedaらはPA 224例と，性・年齢をマッチさせた224例の本態性高血圧を比較し，脳出血発症頻度はPA患者で有意に高かったと報告している¹²⁾．またPA症例ではしばしば脳血管障害を繰り返すため^6,8)，難治性高血圧の治療ではPAの診断は重要な位置を占めるようになった．

　今回われわれはくも膜下出血で発症し，多発脳動脈瘤を認めたPAの1症例に対して，動脈瘤クリッピング術および副腎摘出術を行い良好な結果を得ることができた．本症例に対する治療戦略およびPAにおける脳血管障害について報告する．

　Primary aldosteronism (PA) has been recognized as a relatively benign form of hypertension associated with a low incidence of vascular complications. Recent reports,however,indicate that cerebrovascular accidents are common in PA. We report a case of multiple aneurysms with PA in a middle-aged woman who presented with subarachnoid hemorrhage.

　A 47-year-old woman with a history of untreated hypertension was referred to our hospital for subarachnoid hemorrhage. Cerebral angiography showed multiple small aneurysms. The initial intervention was aneurysm clipping for a ruptured aneurysm at the bifurcation of the right middle cerebral artery. Despite medication, she continued to suffer from uncontrolled hypertension and hypokalemia. She was diagnosed with PA on the basis of elevated plasma aldosterone, suppressed plasma rennin, and a right adrenal tumor detected by abdominal CT scanning. She underwent several more neck clippings for the remaining aneurysms (unruptured), followed by a total right adrenectomy. Histological examination revealed an adrenal adenoma. After the operation, her blood pressure returned to normal without any vasodepressors.

　Recent studies have demonstrated that hyperaldosteronism might have direct vasculo-toxic actions,including remodeling,fibrosis,and proliferation. Cerebrovascular accidents caused by PA are reported to have high rates of mortality and recurrence when the PA is overlooked or untreated. Physicians must be alert to the possibility of PA in patients with hypertension and persistent hypokalemia,especially in those who are young or middle-aged. We also recommend screening for intracranial aneurysms by low-invasive magnetic resonance angiography.