外傷性中大脳動脈閉塞症—本邦報告例25例の検討

POST-TRAUMATIC MIDDLE CEREBRAL ARTERY OCCLUSION: CASE REPORT AND AN ANALYSIS OF TWENTY-FIVE CASES REPORTED IN JAPAN

I．はじめに

　頭部外傷後，何らかの意識鮮明な期間，すなわちlu—cid intervalをおいてから，片麻痺，意識障害，脳局所症状を主症状として発症する外傷性中大脳動脈閉塞症は，とくに頭蓋内血腫との鑑別ということで，近年，注目されてきた。本症の病因については従来から1）内頸動脈からの塞栓，2）血管攣縮，3）血栓形成，4）解離性動脈瘤があげられている。しかし，本症は比較的軽い外傷でも起こること，遅いものでは受傷後数カ月もたつて発症するものがあることから，動脈硬化があるような高令者に起こつた場合に，それが外傷性なのか，動脈硬化によるもので外傷とは無関係なのか，ときに補償問題ともからんで問題となるところである。

　最近，著者らは，自動車事故後に発症した血管攣縮によると思われる55歳男性の本症を経験したが，今回，本邦報告例を集計するとともに，とくに動脈硬化との関連を中心に，若干の検討を加えてみた。

Post-traumatic middle cerebral artery occlusionhas recently been given attention because of itsclinical similarity to intracranial hematoma. Severalexplanations about the pathogenesis have alreadybeen made by many authors.

Our reported case was a 55-year-old male de-veloped right hemiplegia and aphasia after an auto-mobile accident. Carotid arteriography demonstratedlocalized narrowing of the left middle cerebralartery. Follow-up arteriography 25 days latershowed the artery to be completely patent. Thepossible pathogenesis in this case was arterial spasm.

An analysis of twenty-five reported cases in Japanwas carried out and the influence of atherosclerosisto the pathogenesis of post-traumatic middle cere-bral artery occlusion was discussed.

The age of the patients ranged from 1 year and10 months to 71 years, and the average was 39.4years. The latent period until the symptoms be-came manifested varied immediately after to 3months from the time of injury. Causative injurieswere relatively mild in many cases. Intracranialpressure increased in 50 per cent of the reportedcases. An occlusion of the main stem of the middlecerebral artery was present in 15 of the 24 cases,and more distal portion in others.

The influence of atherosclerosis to the patho-genesis causes discussion especially in case of oldperson who developed symptoms late after injury.Two groups, above and below forty-five years old,were compaired in terms of severity of trauma andof the latent period. It is worthy of note thatyounger person were involved more easily by mildertrauma in comparison with older group. Therewas no relationship between age and latent period.Five of the 6 died cases were above forty-five. We,however, could not find out the apparent differencein clinical features between older and younger group.We infer there is a slight difference in mechanismof genesis between both groups; sclerotic vesselsmay well occur dissecting aneurysm and thrombusformation due to intimal damage because of theirfragility, and in the vessels of younger person,trauma may well cause a spasm. This may explainwhy the younger persons tend to be affected bymilder trauma.