Intracranial haemorrhage
Bleeding within the fixed skull can rapidly raise intracranial pressure, reduce cerebral perfusion and cause herniation; the location and mechanism classify extradural, subdural, subarachnoid or intracerebral haemorrhage, but every type needs urgent CT, physiological stabilisation and specialist escalation.
Definition
Intracranial haemorrhage is bleeding within the cranial cavity, classified as extradural, subdural, subarachnoid or intracerebral according to the compartment involved.
First principles
The skull is a fixed box
Brain tissue, blood and CSF share a fixed cranial volume. An expanding haematoma initially displaces CSF and venous blood, but compensation fails as volume increases; intracranial pressure rises, cerebral perfusion falls and brain tissue can herniate across the falx, tentorium or foramen magnum.
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