日本住血吸虫症の脳波—脳症型の症例における観察

EEGic study on SCHISTOSOMIASIS JAPONICA

I．緒言

　甲府地方でみられる意識障害や発作性疾患の中で，日本住血吸虫症（以後「日虫症」とする）が原疾患と思われる症例がある。日虫症は日本住血吸虫（以後「日虫」とする）の幼虫の経皮感染により発症する。体内に入つた幼虫は主として門脈系に生棲し，3〜4週間後に成虫となり，産卵を始める。日虫症発症の機制としては，この虫卵の栓塞による障害あるいは虫卵に対する生体反応としての障害や，虫体，虫卵の代謝産物による内毒素，アレルギー性反応としての障害が主であり，更には虫体，虫卵による機械的刺激による脈管系への障害などがあげられている。

　日虫症の急性型は初回濃厚感染により発熱と消化器症状や髄膜炎症状を示すものであるが，第2次世界大戦で比国レイテ湾に上陸した米軍の報告^1）（1944年）や有泉^2）（1915年）の報告以後には，甲府地方には全くみられない。一方，慢性日虫感染症は現在でも甲府地方に多数みられ，1966年の山梨県衛生研究所の調査では一有病地の日虫皮内反応陽性者は住民の78％にも及んでいる。

In the Kofu City area there are cases with dis-turbance of consciousness, convulsive seizure, and brain tumor which are thought to be caused by schistosomiasis japonica. In the chronic form of this disease 3 types can be distinguished : the sub-jective type, in which objective symptoms are few but subjective symptoms predominate, such as headache, dizziness, loss of appetite, and lethargy; the hepatic type with liver hypofunction and the cerebral type, which shows principally disturbances of the C.N.S. Ariizumi has classified the cerebral type into the following forms : 1) acute cerebral form ; 2) chronic cerebral form ; 3) symptomatic psychosis ; and 4) portal-systemic encephalopathy (Inose type). In the Kofu area forms 2) and 4) are predominant.

We have reported that the diffuse pattern is found in the EEG of both the subjective and the hepatic types. In this paper we report on the EEG of 5 cases of the cerebral type.

1) On the 5 cases of suspected chronic schisto-somiasis japonica, Case 1 (status epilepticus), Case 2 (jacksonian epilepsy), and Case 3 (psychical sei-zure) showed clinically the symptoms of late epilepsy, and a seizure discharge was present in the EEG in all 3 cases.

2) Case 4 showed headache, papill edema, and neck rigidity, and was diagnosed as brain tumor. However, autopsy showed chronic meningoen-cephalitis with tuberculosis-like tumors surround-ing schistomum japonicum cellular infiltration around the blood vessels, and proliferation of glial cells.

4) In case 5,Schistomum japonicum were discovered by liver biopsy, and the patient showed episodic disorientation, dysarthria, finger tremor,and other mental and nervous disturbances. From these symptoms, as well as hyperammonemia and a slow abnormal EEG (triphasic wave), the case was diagnosed as hepatocerebral disease.

5) The genesis and condition of each case was discussed.