Raised ICP and Hydrocephalus Flashcards
what is the normal range for intracranial pressure
5-15mmHg
what is cerebral perfusion pressure
net pressure gradient that supports cerebral blood flow
list some causes of raised ICP
brain tumour haemorrhage cerebral oedema dural sinus thrombosis hypoxia and hypercapnia hydrocephalus idiopathic intracranial hypertension
describe the headache associated with raised ICP
severe headache that is worse in the morning/on bending over and coughing
may wake patient up from sleep
what are the other features of raised ICP other than headache
nausea and vomiting
blurred vision
papilloedema
focal neurological symptoms
what drugs can help manage raised ICP
mannitol reduces ICP
dexamethasone to prevent cerebral oedema
what surgical interventions are used to reduce ICP
burr hole craniotomy
craniotomy
describe a subfalcine herniation and how it presents
the frontal lobe is pushed under the falx cerebri to the opposite side
present with lower limb weakness
describe an uncal herniation and how it presents
temporal lobe moves under the falx cerebelli as a lateral mass pushes the brain medially
presents with third nerve palsy/blown pupil
describe tonsilar herniation and how it presents
herniation of the cerebellar tonsils though the foramen magnum
presents with ataxia, 6th nerve palsy and positive babinski sign
can be a life threatening herniation as the brainstem is compressed
describe tentorial herniation
compression of the 3rd nerve affecting parasympathetic fibres
describe transcalvarium herniation
herniation of the brain contents through a hole in the skull and dura
what is hydrocephalus
accumulation of excess CSF within the ventricular system of the brain
outline some of the main causes of hydrocephalus
obstruction to CSF flow
decreased resorption
overproduction of CSF - rare, due to choroid plexus tumour
what is non-communicating hydrocephalus
obstruction to flow of CSF occurs within the ventricular system
what is communicating hydrocephalus
obstruction to flow of CSF occurs outwith the ventricular system eg in subarachnoid space or at arachnoid granulations
what are some examples of communicating hydrocephalus
subarachnoid haemorrhage
meningitis
what is hydrocephalus ex vacuo
dilatation of ventricular system and compensatory increase in CSF volume which is secondary to loss of brain parenchyma
occurs in the context of Alzheimers
what are some of the features of hydrocephalus seen in infants
increase in head circumference as sutures have nnot fused
dilated scalp veins and tense fontanelles
setting sun sign
Macewans sign
what is setting sun sign
ocular globes deviated downwards and upper lids are retracted - feature of hydrocephalus
what are some features of hydrocephalus seen in children and adults
large head due to raised ICP sixth nerve palsy unsteady gait due to spasticity in legs cognitive decline nausea and vomiting, blurred vision incontinence
what is the main investigation for hydrocephalus
CT brain
what are the findings on CT of communicating hydrocephalus
generalised enlargement of lateral, third and fourth ventricles
how does aqueduct stenosis present on CT
dilated 3rd and lateral ventricles with normal 4th ventricle
how does a posterior fossa mass present on CT
dilated 3rd and lateral ventricles with abnormal looking 4th ventricle
what is the pharmacological management of hydrocephalus
acetazolomide to reduce CSF production
how is hydrocephalus managed surgically
insertion of ventricular catheter to drain excess CSF into peritoneum or right atrium
what are some of the complications of hydrocephalus shunt
infection
subdural haematoma
shunt obstruction
low pressure state
who is commonly affected by normal pressure hydrocephalus
elderly people, idiopathic in origin
what is the triad of symptoms seen in normal pressure hydrocephalus
abnormal wide based gait
urinary incontinence
dementia
what are the main risk factors for developing idiopathic intracranial hypertension
obese female in third decade
endocrine abnormalities such as PCOS, Cushings
use of OCP, tetracyclines, nitrofurantonin and steroids
how does idiopathic intracranial hypertension present
same as all raised ICP diseases with pulsatile tinnitus
diagnosis of exclusion as no underlying cause for raised ICP
how is IIH controlled
lifestyle such as weight loss
drugs - acetazolomide, prednisolone, loop diuretics
surgical - LP shunt if drugs don’t reverse papilloedema
