IV. INTRACEREBRAL HEMORRHAGE (hypertensive)
A. General Comments
- Intracerebral hemorrhage accounts for about 15% of "strokes".
It is much less common than infarction but more lethal - hemorrhage is
the most common cause of death among cerebrovascular disorders. Intracerebral
hemorrhage is most often due to hypertension, although there are a number
of other etiologies, including AV malformation, ruptured aneurysm, and
leukemia and associated blood dyscrasias. In this module, only hypertensive
hemorrhage will be discussed.
- Hypertension is associated with arteriolosclerosis (a disorder
of small arteries and arterioles). Pathological changes in vessels include
thickening of the vessel walls with increased cellularity, hyalinization
of the media, and the formation of small (micro-) aneurysms known as Charcot-Bouchard
aneurysms. Autoregulation is impaired and vascular permeability increases.
Rupture of blood vessels results in hemorrhage into the substance of the
brain, but the cause of rupture is not clear.
||The thickened hyalinized wall of arterioles, as shown, is characteristic
for arteriolosclerosis associated with hypertension.|
- The age at onset is usually greater than 50. In most cases, occurrence
is associated with chronic hypertension.
D. Most Common Sites
- In the majority of cases hypertensive hemorrhage occurs in the area
of the basal ganglia or thalamus. The pons and cerebellum are less common
E. Clinical Course and Prognosis
- In the majority of cases there is acute onset of headache and rapid
development of stupor followed by coma. Signs and symptoms depend on the
location of the hematoma. CT scan readily reveals the presence of an intracerebral
hematoma. Hemorrhage is not instantly fatal - death occurs in 6-36 hours
in 50-70% of patients. Patients who recover may have good return of neurologic
F. CSF Changes
- CSF is often bloody because the hemorrhage may rupture directly into
the subarachnoid space or intraventricular blood may enter the subarachnoid
space via fourth ventricular outlet foramina.
G. Pathological Changes
- The hemorrhage produces a large cavity filled with clot. This is a
highly destructive, space-occupying lesion. Uncal herniation may occur
with brainstem compression and secondary (Duret) brainstem hemorrhages.
In cases of less severe hemorrhage, resolution may be associated with marked
||An intracerebral hemorrhage is present, extending into the ventricle.|
||The hemorrhage shown above caused increased intracranial pressure, leading
to Duret hemorrages. The Duret (secondary) hemorrhages ( center of section)
are shown in a brainstem section with midbrain structures at the top (aqueduct
and colliculi), midbrain structures at the bottom right (cerebral peduncle
and substantia nigra), pons structures at the bottom left (crossing fibers
in pontine tegmentum).|