腦炎と誤診送院せられし腦腫瘍の1例

A case of Braintumor, Misdiagnosed & Hospitalized under as Japanese Enncephalitis.

第1　はしがき

　日本腦炎（以下腦炎）の診斷方法は種々あるが，最も確實なのは病毒分離であり，最近は補體結合反應も實際的に應用される樣になり，更に電子顯微鏡による診斷も實際化されようとしている。然し腦炎患者を多數経驗した者は柿沼教授^1）の述べられた樣に臨床症状により概ね診斷は確實である。たゞ之のみに頼れば研究室的檢索を缺く爲に類似の症候を呈する他種疾患を腦炎と誤診する危險なしとしない。即當教室松岡^2）はさきに大正13年〜昭和17年迄に當大學入院患者244例中28例は所謂擬似腦炎で實地醫家の誤診率10.3％，當教室の夫れは2.8％であつたことを詳細に報告した。歐米に於ては種類は異るがEconomo型腦炎はその特有な經過，症状が往々腦腫瘍と類似する爲腦腫瘍を之と誤診し或いは逆に，Economo型腦炎を腦腫瘍と誤診した症例報告は必ずしも稀でなく，成書にさえ鑑別すべき疾患として記載されている。例えばSubirana^3）はこの腦炎の背後に腦腫瘍がかくされている事があると注意し，又Dereux^4）は中毒性，傳染性或いは流行性腦炎と腦腫瘍との鑑別診斷上の困難を顧慮して"encéphalite pseudotumorale"なる病名を提唱した。飜つて本邦に於ける所謂擬似腦炎の報告例^{2）5）6）7）}は少數ながら見られるが，腦腫瘍を腦炎と誤診した報告例は松岡^2）の上記報告中1例ある他は余寡聞にして知らない。之により北山教授^8）は昭和21年已に腦炎の鑑別診斷上腦腫瘍の注目すべきことにつき警告した。余も亦昨年當地方の流行時に腦炎と診斷されて教室に紹介され，死後剖檢により腦腫瘍であつた事が判明した1例を經驗したので症例を報告し併せてその由つて來るところの原因を考按し腦腫瘍への補遺をしようと思う。

The differential diagnosis between encepha-litis (Economo-type) and braintumors in Eu-rope and America has long been noticed and many misdiagnosed cases have been reported. But in Japan my case, misdiagnosed and hos-pitali zcd as Japanese Bencephalitis, is the second report.

Patient was 47 years old man. He complained headache and vomiting without particular motives from early in Marh 1948. In May he talked in coherently, miscalculated, lost st-rength of right hand and showed the tremor of both hands. In June he could not walk and had difficulty to speak, to move the right armand leg and moreovre he had turbidity of cons-ciousness and incontinece of urine and stool.

And thus in mental deragnement he came to our clinic on July 4. In addition to these. sometimes he had become feverish and it was in the season where the epidcmy of Japa-nese B encephalitis might ccur, therefore the practising doctor sent him to me as suspected case of Jap. B encephalitis.

When he was hospitalized he had fever of 38ﾟ2C and except the above described symp-tonrms the meningeal irritation was eminent, spinal fluid was clear and its pressure leva-ted, cell counts were normal, protein and sugar increased, bacteria were not demonst-rated. In blood the leucocyte increased in number.

It is characteristic that Jap B encephalitis. beginns suddenly with fever in healthy men and acute periode contimies for 7-10 days and rare cases have the prodrome of mental symptoms but we don't know that these con tinue ovtr a monthes.

The onset of this case was four monthes before, so I diagnosed the case as meninsitis or braintumor. He died on the 6th day from hospitalization. It was proved by autopey that disease was metastatic cancers in left frontal lobe, in left parietal lobe and in right tempo-ral lobe.

The main foctors that the practising doctor misdiagnosed as jap. B encephalitis are as follows: 1) The many symptoms of this case occurs in jap. B encephalitis too, besides this case had occasionally fever.

2) It was in the season when the Jap. B. encephalitis occurs.

3) The braintumors occupied chiefly the so-called silent area, so that the special focal signs were not marked.

4) The tumors were metastatic cancers and symptoms of the primary focus were not eminent and clinical course was relativerapid.