Raised ICP and Hydrocephalus

Question 1

what is the normal range for intracranial pressure

Answer 1

5-15mmHg

Question 2

what is cerebral perfusion pressure

Answer 2

net pressure gradient that supports cerebral blood flow

Question 3

list some causes of raised ICP

Answer 3

brain tumour 
haemorrhage 
cerebral oedema 
dural sinus thrombosis 
hypoxia and hypercapnia 
hydrocephalus 
idiopathic intracranial hypertension

Question 4

describe the headache associated with raised ICP

Answer 4

severe headache that is worse in the morning/on bending over and coughing
may wake patient up from sleep

Question 5

what are the other features of raised ICP other than headache

Answer 5

nausea and vomiting
blurred vision
papilloedema
focal neurological symptoms

Question 6

what drugs can help manage raised ICP

Answer 6

mannitol reduces ICP

dexamethasone to prevent cerebral oedema

Question 7

what surgical interventions are used to reduce ICP

Answer 7

burr hole craniotomy

craniotomy

Question 8

describe a subfalcine herniation and how it presents

Answer 8

the frontal lobe is pushed under the falx cerebri to the opposite side
present with lower limb weakness

Question 9

describe an uncal herniation and how it presents

Answer 9

temporal lobe moves under the falx cerebelli as a lateral mass pushes the brain medially
presents with third nerve palsy/blown pupil

Question 10

describe tonsilar herniation and how it presents

Answer 10

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

Question 11

describe tentorial herniation

Answer 11

compression of the 3rd nerve affecting parasympathetic fibres

Question 12

describe transcalvarium herniation

Answer 12

herniation of the brain contents through a hole in the skull and dura

Question 13

what is hydrocephalus

Answer 13

accumulation of excess CSF within the ventricular system of the brain

Question 14

outline some of the main causes of hydrocephalus

Answer 14

obstruction to CSF flow
decreased resorption
overproduction of CSF - rare, due to choroid plexus tumour

Question 15

what is non-communicating hydrocephalus

Answer 15

obstruction to flow of CSF occurs within the ventricular system

Question 16

what is communicating hydrocephalus

Answer 16

obstruction to flow of CSF occurs outwith the ventricular system eg in subarachnoid space or at arachnoid granulations

Question 17

what are some examples of communicating hydrocephalus

Answer 17

subarachnoid haemorrhage

meningitis

Question 18

what is hydrocephalus ex vacuo

Answer 18

dilatation of ventricular system and compensatory increase in CSF volume which is secondary to loss of brain parenchyma
occurs in the context of Alzheimers

Question 19

what are some of the features of hydrocephalus seen in infants

Answer 19

increase in head circumference as sutures have nnot fused
dilated scalp veins and tense fontanelles
setting sun sign
Macewans sign

Question 20

what is setting sun sign

Answer 20

ocular globes deviated downwards and upper lids are retracted - feature of hydrocephalus

Question 21

what are some features of hydrocephalus seen in children and adults

Answer 21

large head due to raised ICP
sixth nerve palsy 
unsteady gait due to spasticity in legs 
cognitive decline 
nausea and vomiting, blurred vision 
incontinence

Question 22

what is the main investigation for hydrocephalus

Answer 22

CT brain

Question 23

what are the findings on CT of communicating hydrocephalus

Answer 23

generalised enlargement of lateral, third and fourth ventricles

Question 24

how does aqueduct stenosis present on CT

Answer 24

dilated 3rd and lateral ventricles with normal 4th ventricle

Question 25

how does a posterior fossa mass present on CT

Answer 25

dilated 3rd and lateral ventricles with abnormal looking 4th ventricle

Question 26

what is the pharmacological management of hydrocephalus

Answer 26

acetazolomide to reduce CSF production

Question 27

how is hydrocephalus managed surgically

Answer 27

insertion of ventricular catheter to drain excess CSF into peritoneum or right atrium

Question 28

what are some of the complications of hydrocephalus shunt

Answer 28

infection subdural haematoma shunt obstruction low pressure state

Question 29

who is commonly affected by normal pressure hydrocephalus

Answer 29

elderly people, idiopathic in origin

Question 30

what is the triad of symptoms seen in normal pressure hydrocephalus

Answer 30

abnormal wide based gait urinary incontinence dementia

Question 31

what are the main risk factors for developing idiopathic intracranial hypertension

Answer 31

obese female in third decade endocrine abnormalities such as PCOS, Cushings use of OCP, tetracyclines, nitrofurantonin and steroids

Question 32

how does idiopathic intracranial hypertension present

Answer 32

same as all raised ICP diseases with pulsatile tinnitus | diagnosis of exclusion as no underlying cause for raised ICP

Question 33

how is IIH controlled

Answer 33

lifestyle such as weight loss drugs - acetazolomide, prednisolone, loop diuretics surgical - LP shunt if drugs don't reverse papilloedema