Raised ICP Flashcards
What is the normal range for ICP?
5-15 mmHg
What is CPP?
Cerebral perfucsion pressure
The net pressure gradient causing cerebral blood flow to the brain
How is CPP calculated?
CPP = MAP - ICP
What is the Monro-Kellie doctrine?
Relationship between contents of the cranium and ICP
What are the major components found in the cranium?
Brain tissue
CSF
Blood
What happens if the volume of one of these components rises?
Causes a rise in ICP
So one of the other components needs to decrease in volume
What are the main compensatory mechanisms for raised ICP?
Increased blood drainage
Increased CSF drainage
Brain herniation
What can cause raised ICP?
Idiopathic intracranial hypertension Traumatic head injuries Infection Tumours Hydrocephalus
What are features of raised ICP?
Headache - worse in morning
Vomiting
Reduced consciousness
Papilloedema
Cushing’s triad
What is Cushing’s triad?
Widened pulse pressure
Bradycardia
Irregular breathing
How is raised ICP investigated?
Neuro imaging
Invasive ICP monitoring
How is ICP monitored?
Subarachnoid bolt
Epidural bolt
External ventricular drain
How is raised ICP managed?
Find underlying cause
Head elevation to 30 degrees
IV mannitol
Controlled hyperventilation
CSF drainage
How does controlled hyperventilation work?
Reduce pCO2 -> vasoconstriction of cerebral arteries -> reduced ICP
How is CSF drained?
Catheter placed into lateral ventricles
Repeated LP
Ventriculoperitoneal shunt
What is idiopathic intracranial hypertension?
Condition where there is raised ICP without a cause
What are risk factors for idiopathic intracranial hypertension?
Obesity
Female sex
Pregnancy
Drugs
- COCP
- steroids
- lithium
What are features of idiopathic intracranial hypertension?
Headache
Blurred vision
Papilloedema
Enlarged blindspot
How is idiopathic intracranial hypertension managed?
Weight loss
Diuretics
Topiramate
Repeated LP
What is hydrocephalus?
Accumulation of CSF in the cerebral ventricles
How can hydrocephalus be classified?
Obstructive
Communicating
What is obstructive hydrocephalus?
Blockage to natural ventricular drainage system
What can cause obstructive hydrocephalus?
Tumour
Cysts
Congenital
What is communicating hydrocephalus?
Reduced absorbance of CSF by arachnoid villi
What can cause communicating hydrocephalus?
Infective meningitis
SAH
Congenital
Normal pressure hydrocephalus
What is normal pressure hydrocephalus?
Ventricular dilatation in the absence of raised CSF pressure
What are teh features of normal pressure hydrocephalus?
Parkinsonin gait
Urinary incontinence
Dementia
How is normal pressure hydrocephalus managed?
CSF shunt
What are features of hydrocephalus?
N+V
Morning headache
Altered GCS
Blurred vision
How is suspected hydrocephalus investigated?
CT brain
LP
What is seen on a CT head in hydrocephalus?
Enlarged ventricles
Loss of sulcal gyral pattern
CSF exudation from ventricles = hypodensity around ventricular margins
How is hydrocephalus managed?
Insertion of external ventricular drain
Treat underlying cause
