わが国における島性低血糖症—特に慢性てんかんと誤まられやすい点について

SPONTANEOUS HYPOGLYCEMIA IN JAPAN

I．はじめに

　昏睡ないしもうろう状態，痙攣発作を起こす疾患には，慢性てんかんと症候てんかんとがあり，後者は，現在他に何か原因となる疾患があつて，そのひとつの症候として以上の発作を呈するものをいう。この中で，われわれが，日常経験するものには，脳梅毒，進行麻痺，脳動脈硬化症，脳出血，脳軟化，脳腫瘍，脳外傷，脳炎および脳膜炎まれに脳寄生虫病などの脳疾患，また酒精，麻薬，睡眠剤などによる各種中毒，その他，糖尿病，尿毒症，疫痢，肝疾患あるいは下垂体・副腎・膵（島性低血糖症）などの内分泌性疾患がある。これら疾患は，病歴や臨床所見を総合して，これを鑑別することが，かならずしも困難ではない。しかし，島性低血糖症は，昏睡や痙攣発作が反復して現われ，発作時のほかにはほとんど臨床所見がなく，慢性てんかんに似ているため，しばしば，それと誤まられることが少なくない。本症は，ランゲルハンス氏島（以下ラ氏島と略す）の機能亢進によつて，過インシュリン状態をきたし，その原因の多くは，ラ氏島腺腫と増殖による。

　われわれは，昭和34年，昏睡ないしもうろう状態，痙攣発作が前景にたち，長期間慢性てんかんとされていた症例で，原因が，ラ氏島腺腫および増殖によることを確かめ得た各1例を報告したが^23），今回さらに，酒精てんかんと診断されていたものの原因が，ラ氏島増殖による過インシュリン症であつた1例を経験した。これら自験3例は，いずれも一見，慢性てんかんに似た症候を呈し，昏睡ないしもうろう状態が，きまつて早朝空腹時に起こり，ときに痙攣を伴う。この発作が，他種原因によるそれと異なるところは，高張ブドウ糖静注によつてただちに覚醒し，常態に復する点である。もちろん，発作中の血糖値はいちじるしく低く，かつ，EEG所見に異常波の出現を認めるが，他の臨床検査成績に著変がない。

As the chief causes of the spontaneous hypoglycemia, the adenoma and the hyper-plasia of the islets of Langerhans have been considered and so clinically the attack of coma or twilight condition, occasionally convulsive seizure are mainly observed in the early morn-ing.

In EEG, spike and slow wave complex are seen and sometimes these findings may lead to misiagnosis as epilepsy.

Recently we had three cases, two cases with hyperplasia of the islets of Langerhans and one case with adenoma, which had been tre-ated as epilpsy for a long duration. Those patients had been suffered from the repeated hypoglycemic attacks and some irreversible organic defects in the central nervous system were recognized after surgical treatment, even though the blood sugar level became normal.

From the stand point that the spontaneous hypoglycemia is mainly due to its adenoma, those patients with hypoglycemia must cure without residual pefects by early surgical tre-atment. Considering to the fact that this dis-order might be misdiagnosed as epilepsy, we discussed on our three cases and the other cases reported in Japan.

In Japan, 26 cases have been reported, 11cases of which were misdiagnosed as epilepsy, 2 cases as neurosis and one case as hysteria, encephalitis, Japanese encephalitis, psychoge-nic reaction, and hypotension, respectively. The duration until the operation or death is within one year in 2 cases, 1-2 years in 4 cases, 2-5 years in 7 cases, 5-10 years in 8 cases. In 9 cases of 26 the following various residual defects had been described, and some of those cases showed two or three defects in each case; speech disturbance was seen in 6 cases, personality change in 4 cases, failure of memory or dementia in 4 cases, diabetes mellitus and compulsive laughing in every one case.

We would like to emphasize that in the patients with spontaneous hypoglycemia resi-dual organic defects may develop if it would be treated as epilepsy for a long time.