Lobar Hemorrhage
Finally, we should point out that not all strokes fall neatly into the categories that we have described. There remain strokes whose causes baffle even the experts. Other strokes have causes that are beyond the scope of this introduction. One of these (amyloid angioathy) produces lobar hemorrhages which are particularly common in the very elderly.
For more information about Lobar Hemorrhages:
More About Lobar Hemorrhage
It has recently been recognized that small arteries supplying the superficial regions of the cerebral hemispheres may develop deposits of an abnormal protein called amyloid in the extremely elderly. In some cases, this material can weaken the walls of these vessels to the extent that they rupture and cause hemorrhages in the superficial regions of the hemispheres. These are termed lobar hemorrhages (presumably because they involve outer portions of the various lobes of the brain). Unlike the intracerebral hemorrhages involving midline penetrating vessels, superficial lobar hemorrhages can occur in individuals who have had normal blood pressure throughout their lives.
Case of RK
R.K. is an 84 year-old woman who has had normal blood pressure all her life. She suddenly developed a headache, and paralysis of her left arm and leg. She died 24 hours later.
This is R.K.'s brain. Locate the hemorrhages. Notice that the hemorrhage is primarily located in the right frontal lobe.
This is a vessel near the hemorrhage. Its wall is thick, and irregular, and it shows an unusual red coloration in this hematoxylin and eosin stained section. This material has been identified by immunohistochemistry as beta-amyloid. Click here to see vessels from R.K.s brain stained for this abnormal protein.
Can you see the red stained areas which indicate the presence of beta-amyloid in the walls of the vessels?