Pure cortical arterial injuryによる急性硬膜下血腫:自験例14症例からの考察

Acute subdural hematoma due to pure cortical arterial injury:analysis of 14 cases

I．はじめに

　急性硬膜下血腫（以下ASDH）は通常脳皮質の挫傷の結果，動静脈が損傷されて発生してくる．

　一方，高齢者や脳に萎縮のある場合は，比較的軽い外傷で脳実質には挫傷を伴わず皮質動脈のみが損傷してASDHが発生したという報告が散見されるが^3,4,6），まとまった症例数の報告は少ない．われわれは過去12年間に14例のpure cotical arterial injuryによるASDHを経験したので，その臨床的特徴について報告する．

Pure cortical arterial injury is defined as an acute subdural hematoma (ASDH) due to micro laceration of the cortical artery without cerebral contusion. We analyzed this peculiar ASDH in 14 cases.

This ASDH has the following characteristics.

1) This disease develops in elderly persons after minor head trauma.

2) After a relatively long lucid interval, the con-sciousness level of these patients decreases rapidly to semicoma or deep coma.

3) Brain atrophy, atherosclerosis and a tendency to bleed (drugs, hemodialysis, thrombocytopenia, etc.) are involved in this hematoma.

4) The clinical outcome is generally poor because of systemic complications.

The authors infer the mechanism of pure cortical arterial injury to be as follows. Minor hemorrhage occurs due to direct impact damage after trivial head trauma, but physiological hemostatic actions are set in motion. After a lucid interval, rebleeding from the in-jured cortical artery causes massive subdural hemor-rhage.