日本住血吸虫症の脳波—門脈圧亢進症群における観察

EEG OF THE PATIENTS WITH SCHISTOSOMIASIS JAPONICA : STUDIES ON THE CASES OF THE HEPATIC FORM WITH PORTAL HYPERTENSION

I．はじめに

　日本住血吸虫症（以後「日虫症」とする）は日本住血吸虫（「日虫」とする）の皮内感染によりもたらされる。日虫感染者の症状は，岡部ら^1）によると，半数は無症状であるが，半数は食欲不振，るいそうなどの消化器症状と頭痛，頭重感，めまいなどの神経症状を訴える。これらの消化器症状や神経症状を自覚的には認めながら，他覚的には所見のないものを著者ら^2）は「自覚症状群」と呼び，一方，他覚的に肝障害を認めるものを「肝疾患群」と呼んで^3），この群の中に肝脳疾患を含めた。また，頭痛，めまい，知覚・運動障害および痙攣などを示す群は有泉ら4）により脳日虫症型と呼ばれ，この中に門脈側副路性疾患（肝脳疾患特殊型）が含まれている。なお，これらの症例に対する外科的治療成績については志田ら^5）の報告がある。

　著者らはこれら慢性日虫症の各群について脳波学的研究をすすめてきた^2,3,6）。その結果，「日虫症自覚症状群」の脳波は異常率26％で，異常の内容はα波に散在性の徐波を混在するものが多く，パタンの特徴は汎性αの傾向を示した。「肝疾患群」では異常率は32％であるが，内容は「自覚症状群」より著しく悪く，広汎性にθ波が目立つて出現する例が主で，時にδ波も認められた。脳症型の脳波は臨床症状に対応するパタンであり，発作性疾患では棘波がみとめられた^6）。

The types of chronic schistosomiasis japonica were classified as follows ; 1) form with only sub-jective symptom, 2) cerebral form, 3) hepatic form (including the form with portal hypertension).

The authors obtained the following EEG-findings ; slightly abnormal such as diffuse alpha pattern or alpha pattern with random theta waves, remarkably abnormal such as slow wave bursts or epileptic discharges, and also remarkably abnormal such as diffuse slow waves or much theta waves with some delta waves in the cases of the aboveclassified forms respectively.

In this study, on the cases of the hepatic formwith portal hypertension, the authors investigated their electro-clinical correlations between EEGs and several clinical findings of serum γ-globuline and ammonia levels, splenomegaly by liver-spleen scincigram and esophageal varix.

The subjects were 49 patients with the hepatic form of schistosomiasis japonica with portal hyper-tension. On 22 of 49 cases, the follow-up studies were made after splenectomy.

The results were as follows ;

1) Abnormal EEGs were obtained in 29 of 49 cases (59%), borderline in 4 cases (8%) and normal in 16 cases (33%) under resting condition.

2) Most cases of the abnormal EEGs showed 8-9 cps slow alpha rhythm with 6-7 cps random theta waves, diffuse 6-7 cps theta waves withscattered 3 cps delta waves and episodic delta bursts in the fronto-centroparietal areas.

3) The abnormal EEGs had statistically a close relationship to increase in serum γ-globuline levels (P<0. 01) and hyperammonemia (P<0. 01), and had also a relationship to histopathological changes of the liver, i. e. liver cirrhosis or fibrosis diagnosed by a large biopsy (surgical, not needle).

4) The EEGs of the cases after splenectomy re-mained unchanged in spite of the improvement of leukopenia, thrombocytopenia and portal hyper-tension, disappearence of esophageal varix and also decrease of serum ammonia levels.