急性播種性脳脊髄炎の病理組織学的研究

The Morbid Anatomy of the Acute Disseminated Encephalomyelitis

I．まえがき

　古来，ある種の熱性疾患の経過中ないし経過後や，ある種の予防接種後に急性に経過する脳脊髄膜炎が発症することが知られており，その臨床症状は中枢神経系の白質に多発する病変を示すものであり，その病理解剖学的特徴は静脈周囲性の細胞浸潤および脱髄からなるものである。

　これらは原病ないし予防接種などとの時期的関係からpost-およびparainfectious encephlalomyehitis，postvaccinial encephalomyelitis，post-exanthematous encephalomyelitisなどと呼ばれ，また，直接原病の名を冠して，たとえば麻疹（後）脳炎、狂犬病予防接種後脳炎などと呼ばれているが，病理解剖学的ならびに組織学的には病変の強弱こそあれ，本質的には同一の組織像が認められ，原疾患によって組織像に違いがみられないことから，一括してacute disseminatedencephalomyelitis（急性播種性脳脊髄炎）あるいはacute perivascular InyelinocDasisと呼ばれている^1）。

　A histopathological study of acute disseminatedencephalomyelitis were made by the author withreporting ten autopsy cases, in which four casesaccompanied with measles, two with acute febrileexanthemata of unknown etiology, one with theinfection of the upper respiratory tract, and oneoccurred after the vaccination of small pox and twoadult cases after antirabies vaccination.

　Three cases showed the early lesion: smallamount of mononuclear cell infiltrates to the edematous perivascular area. These cells were mostlylymphocytes and histiocytes. Demyelination was notremarkable. Blood vessels were markedly engorged. Pyknosis and disappearance of oligodendroglialnuclei were noted in various degree. The lesionswere scattered throughout the central nervoussystem, but more scanty than the advanced cases.In a case, localization of the lesions were restrictedto the white matter of the temporal lobes and otherparts of the central nervous system showed merelysevere congestion and edema. This case suggeststhat an elaborate Instopathological observations areneeded in the cases of early lesion to differentiatefrom the toxic encephalopathy.

　Three cases showed marked demyelination withmononuclear cell infiltration of the perivasculararea and paravascular white matter. In a case, anamount of plasma cells were noted, mainly in theperivascular area, as well as histiocytes and lymphocytes. In two cases karyorrhexis and nucleardebris were remarkably noted. Many histiocytesevolved to the macrophages.

　From the findings of the six cases above, it isnot impossible to consider that mononuclear cellinfiltration preceed the break clown of myelin andnot vice versa.

　Two cases were at the advanced stage of repairing. A large number of hypertriophied astrocytesintermingled with scattered macrophages. Someaxis cylinders showed bulbing. Secondary degeneration of nerve fibers was prominent not onlyadjascent to the perivascular lesion but also in thecorpus callosum and descending fiber tracts ofbrain stem and spinal cord. Two cases of encephalomyelitis following the preventive innoculationof Pasteur vaccination showed severely and widespread necrotic lesion with hemorrhage in the spinalcord. Perivascular lesion in the other part of thecentral nervous system were essentially the samein character to those of the other cases of acutedisseminated encephalomyelitis.

　The lesions occurred most frequently in thecerebrid white matter and the basal portion of pons.

　The similarlities of the early lesion of theexperimental allergic encephalomyelitis of theanimals to the acute disseminated encephalomyelitisof man were briefly discussed.