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Spontaneous intraparenchymal hemorrhage in the basal ganglia is frequently associated with the rupture of Charcot-Bouchard aneurysms (also known as miliary aneurysm or microaneurysms). These aneurysms are rare under the age of 50 and occur most commonly in the brains of hypertensive patients.
Vessels
affected: They
occur on small arteries 100-300 micron in diameter and are seen as outpouchings
of the vessel walls, often partly filled by thrombus. The aneurysms are often
seen at branches of vessels and were multiple on some arteries.
Location:
They
are most commonly located at the putamen, globus pallidus, and thalamus. Can
be seen in other areas such as the caudate, internal capsule, centrum
semioale, and cortical gray matter.
They
occurred mainly on the lateral branches of the striate arteries or on the
penetrating vessels in the cerebral cortex. The lateral striate (lenticulostriate)
group of arteries make a right-angled turn inward and upward to supply the
caudate nucleus after they supply the putamen. This may be a contributory
factory for the predisposition of microaneurysms formation in the putamen.
Histopathology:
They
should be distinguished from pseudoaneurysms which are due to blood
accumulating around a blood vessel rather than to dilatation of the lumen.
Severe
vascular changes with fibrinoid necrosis and thrombotic occlusion of
arterioles within the brain in the acute stage.
Vessels
that had undergone spasm in patients who survived long enough (a month or
more) after a subarachnoid hemorrhage may show a reduction of the lumen due
to proliferation of the intima.
Rupture and destruction of the elastic lamina may
be seen in the aneurysmic segment of the blood vessel.
NeuroLearn NeuroHelp Vascular For Comment: KarMing-Fung@ouhsc.edu