Cerebral Oedema and ICP Flashcards
Cerebral oedema
Common cause of death of stroke and TBI.
Excessive abnormal accumulation of water within brain.
How oedema occur?
Water comes into the brain through BBB (blood brain barrier) as water follows albumin to brain.
Increase fluid in brain means
increase in intracranial pressure (ICP)
Normal ICP
5-15 mmHg
Consequences of high ICP
Higher pressure = less oxygen in brain. Leads to ischaemia. Leads to neuronal cell death. Leads to loss of function. Leads to death and disability.
Signs of raised ICP
Decreased LOC.
Bradychardia.
Hyperventilation.
Dilated/sluggish pupils.
What does brain experience when you have raised ICP?
Hypoxia and lactic acidosis.
Excess acid in brain = dilate cerebral arteries = further vasodilation.
If ICP continues to increase?
Hypercapnia.
Increased CO2 levels > potent vasodilator > further increased ICP.
Brain herniation.
Loss of autoregulation.
How does brain compensate for raised ICP??
Venous vasoconstriction: reduce venous volume = decreased volume within skull.
Shunt off CSF: brain gets rid of CSF = reduced CSF volume = reduce volume within skull.
Brain herniation
Brain is pushed where it shouldn’t be. This may be due to swelling.
Subfalcine herniation
Singular.
Midline shift.
Transtentorial herniation
Pushes down towards brain stem.
Can cause sluggish/dilated pupils; sign of raised ICP.
Tonsillar herniation
Cerebellum.
Associated with respiratory and cardiac function
Death
Management of Increased ICP
Hyperventilation: vasodilation = reduced volume.
Head elevation: drainage from head.
Hyperosmotic agents: mannitol, hypertonic saline.
Steroids.
Barbituates.
Most helpful in management of increased ICP
Decompressive craniectomy.
Takinng out portion of skull hence reduces the pressure/volume.
