[Histological and morphometrical studies on small arteries in normal brainstems with special reference to the pathogenesis of the hypertensive brainstem hemorrhage].
Plasmatic arterial necrosis and microaneurysm of small arteries are preceded by smooth muscle cell loss and the rupture of these arterial lesions is a direct cause of hypertensive intracerebral hemorrhage. The hypertensive brainstem hemorrhage occur exclusively in the pons. To elucidate whether there are differences of underlying arterial lesions between each part of the brainstem or not, small arteries in normal 34 autopsied brainstems were investigated histologically and morphometrically. Histological study revealed the predilection of the occurrence of plasmatic arterial necrosis, microaneurysms and fibronodular arterial lesions in the hypertensive pons. These lesions occurred predominantly in the small arteries 100-300 microns in diameter in the basal part of hypertensive pons, and were rare in the other parts of hypertensive brainstems and in normotensive brainstems. A negative correlation between the ratio of number of smooth muscle cell nuclei to the area of tunica media and age was demonstrated morphometrically. The ratio in the hypertensive group was significantly lower than that of the normotensive group. In addition the mean ratio in the pons was significantly lower than that in the midbrain and the medulla oblongata in the hypertensive group. These results are consistent with the fact that the hypertensive brainstem hemorrhage predominantly occur in the pons and primary bleedings in the other parts of the brainstem are rare.
Kanai
H
H
Department of Neurosurgery, Kakegawa City General Hospital, Shizuoka, Japan.
Yamada
K
K
Yoshida
Y
Y
D000368:Aged; D000369:Aged, 80 and over; D001933:Brain Stem / Q000098:blood supply* / Q000473:pathology*; D002536:Cerebral Arteries / Q000473:pathology; D002543:Cerebral Hemorrhage / Q000209:etiology* / Q000473:pathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D011149:Pons / Q000473:pathology; D017540:Tunica Media / Q000473:pathology