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Intracranial
Hemorrhage |
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Spontaneous intracranial haemorrhage accounts
for about 15% of all strokes.
Cerebral haematomas are most commonly caused by hypertensive vascular damage
The most common cause of cerebral haemorrhage is hypertensive vascular damage.
Prolonged hypertension results in arteriosclerosis and in the development of
small microaneurysms (Charcot-Bouchard aneurysms), which predispose to vessel
rupture, resulting in a haematoma. The common sites for hypertensive
intracerebral haematoma are those supplied by fine perforating vessels (basal
ganglia, internal capsule, thalamus, cerebellum and pons).
In patients over the age of 70 years, 10% of cerebral haemorrhages are caused by
the presence of cerebral artery amyloid, which is composed of b(A4) protein.
This causes haematomas, seen in the periphery of cerebral hemispheres (lobar
haemorrhages). This type is associated with a better clinical outcome than the
deep bleeds associated with hypertension.
Less common causes of a cerebral haematoma are bleeding into a tumour, rupture
of vascular malformations, cerebral vasculitis, bleeding associated with
disordered coagulation, and bleeding occurring in association with leukaemias.
Macroscopically, haematomas appear as a large blood clot, causing compression
and damage to adjacent brain. Large haematomas in the basal ganglia or thalamus
often rupture into the ventricular system. If the patient survives a bleed, the
haematoma is removed by phagocytic cells; astrocytic gliosis takes place,
leaving a cavity stained yellow-brown with haemosiderin.
Large bleeds that cause raised intracranial pressure, and those that rupture
into the ventricular system, are usually fatal.
Sub-arachnoid haemorrhage is most often caused by a ruptured berry aneurysm
Bleeding into the sub-arachnoid space (between the arachnoid and the pia) is
termed sub-arachnoid haemorrhage. A cause of stroke from adolescence to old age,
it accounts for about 5% of all cases. In most cases, the cause of sub-arachnoid
bleeding is rupture of a berry aneurysm; less common causes are rupture of an
intracerebral haematoma into the sub-arachnoid space or rupture
of a vascular malformation.
Macroscopically a layer of blood is present over the brain surface in the sub-arachnoid
space. Blood is therefore present in the cerebrospinal fluid (CSF) and can be
detected on lumbar puncture. There are two effects of sub-arachnoid haemorrhage:
1 Blood around vessels causes vascular spasm and leads to widespread cerebral
ischaemia and brain swelling.
2 There may be blockage of CSF resorption, causing acute hydrocephalus.
About 30% of patients die immediately; others who present with headache and
signs of meningeal irritation may have surgical intervention and clipping of the
aneurysm. In the absence of operative intervention, 30% of patients have a
re-bleed within one year, most within one month of their first bleed. A
long-term complication is development of hydrocephalus caused by blockage and
fibrosis in the CSF pathways. |
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We give here simplified and accurate information about the disease
Info@somalidoc.com |
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