Raised ICP and Hydrocephalus Flashcards
What are the 3 components of the skull?
Brain
Blood
CSF
Where is CSF produced?
Choroid plexus - found in the lateral ventricles.
What does obstruction to the flow of CSF result in?
Raised ICP
Hydrocephalus
What is autoregulation?
The action taken by the body to keep cerebral blood flow constant, despite fluctuating BP.
What is an obstructive hydrocephalus?
Hydrocephalus resulting from a mass preventing the flow of CSF around the ventricles.
What is a communicating hydrocephalus?
Hydrocephalus resulting when CSF cannot be absorbed into the arachnoid granulations. These are blocked - can be due to subarachnoid haemorrhage or meningitis.
What are early symptoms of raised ICP?
Decreased LOC Headache Pupillary dysfunction and/or papilloedema Change in vision Nausea and vomiting
What are late symptoms of raised ICP?
Coma Fixed, dilated pupils Hemiplegia Bradycardia Hypotension Hyperthermia Increased urinary output
Which medications can be used to treat raised ICP?
Diuretics (usually hypertonic saline)
Barbiturate coma
Antiepileptics (prophylactically)
Surgery (final stage - a VP shunt)
What is the most common cause of obstructive hydrocephalus?
Aqueductal stenosis
What appears enlarged in a communicating hydrocephalus?
Lateral ventricles
3rd ventricle
4th ventricle
How is raised ICP treated?
Maintain head at midline at 30-45 degrees elevation
Loosen collars to encourage blood flow
Maintain fluids and treat hyperthermia
Manage normocarbia
in which group of individuals will hydrocephalus develop in, at normal ICP levels?
Elderly
What is hydrocephalus?
Accumulation of fluid due to excess in the ventricular system.
What changes are seen on CT in those with normal pressure hydrocephalus?
The size of the ventricles will be disproportionate to the sylvanian fissures.
How is normal pressure hydrocephalus treated?
VP shunt
What is idiopathic intercranial hypertension?
Raised ICP of an unknown cause. There will be no ventricular dilatation.
Most common in young woman who are overweight.
What is a complication of IIH?
Blindness
How is IIH treated?
Rapid weight loss
Diuretics
Carbo-anhydrase inhibitors
Can also fit a VP shunt.
Why does the head not enlarge in adults with hydrocephalus (but does in children)?
As the skull is rigid. In children the skull is more flexible and can therefore move to compensate for rises in ICP.
What are the causes of raised ICP?
SOL Diffuse oedema Raised CSF Increased venous volume Physiological
What is cerebral perfusion pressure dependent on?
Mean arterial pressure
Intracranial pressure
What is hydrocephalus ex vacuo?
When the ventricular system dilates due to a loss of brain parenchyma.
Can be due to AD or an infarct.
