2(E): Raised ICP Flashcards
What is normal range ICP
5-15mmHg
What ICP is considered raised
Above 20mmHg
What 4 focal mass effects cause raised ICP
Bleed: extradural, SAH
Intracranial tumour
Abscess
Hydrocephalus
What diffuse mass effective lead to raised ICP
Vasogenic oedema
Cytogenic oedema
Ischemic stroke
Meningitis
What is cytogenic oedema
Accumulation fluid in brain parenchyma due to build up Na+ and H2O
What is vasogenic oedema
Build-up fluid in interstitial space
What causes oedema
Ischaemic Strokes
Meningitis
Explain ‘early’ clinical-presentation of raised ICP
- Headache: worse in mornings, on sneezing, coughing, moving head
- Vomiting
- Lethargy
- Altered mental state
What are late clinical symptoms of raised ICP
- Continuous vomiting
- CN3 Palsy
- Decrease in GCS
- Cushing’s triad (bradycardia, HTN, irregular respiration)
- Coma and death
What may be seen on fundoscopy in raised ICP
Papilloedema
What doctrine explains why raise in ICP can cause herniation
Monroe-Kellie doctrine
What is uncal herniation also called
Trans-tentorial
What is trans-tentorial herniation
Uncus of hippocampus is forced under tentorium
What are three signs of transtentorial herniation
- CN3 Palsy
- Ipsilateral weakness
- Occludes PCA - causing ischaemic stroke of occipital lobe = homonymous hemianopia with macula sparing
How does CN3 palsy present
- Fixed Mid-Dilated Pupil
- Eye deviated down and out
What is central herniation
Diencephalon passes through tentorium
How does central herniation present
Sunset eyes
- Paralysis of upward gaze meaning eyes appear downwards
- Lower eyelid may cover lower half of pupil
- Only sclera is visible between pupil and upper eyelid
When is sunsetting of the eyes particularly common
Children with raised ICP
What is cingulate herniation also known as
Subfalcrine
What is sub-falcine herniation
Herniation of cingulate gyrus through fall cerebri
What does sub-falcrine herniation cause
Compress ACA causing ischaemic stroke
What is upward cerebellar herniation
Vermis is pushed upwards through transtentorium
What is tonsillar herniation
Herniation cerebellar tonsils through foramen magnum
How does tonsillar herniation present
- Compress brainstem causing respiratory and cardiac dysfunction
- Headache, neck stiffness
- Drop in GCS
What are indications for ICP monitoring
- Hydrocephalus
- TBI
- High-risk hydrocephalus (SOL, IIH, SAH, Reye’s)
What are contraindications for ICP monitoring
Anticoagulation
Brain abscess
What are the three types of ICP monitoring
EVD
Subarachnoid bolt
Extradural bolt
What is external ventricular drain also known as
Fluid-filled transducer ventriculostomy
What is gold-standard for ICP monitoring
EVD
What is the advantage of external ventricular drain
Able to drain CSF
Where is EVD placed
Kocher Point
What is the advantage of subarachnoid bolt
Less invasive than EVD
What is the problem with subarachnoid bolt
- High infection risk
- Limited therapeutic use
What is advantage of epidural bolt
- Less Infection risk then subarachnoid bolt
What is problem with epidural bolt
- Limited use
If raised ICP is suspected, how should patient be approached
A-E
IV Access
O2 if required
Basic investigations to determine cause
If GCS less than 8, how is patient managed
- Nurse at 30’
- Anaesthetist to intubate
Treat ICP if signs herniation:
- Mannitol or Hyper-osmotic Saline
- Hyperventilation (Ambubag)
If GCS is more than 8 in suspected raised ICP what is ordered
CT Scan to identify lesion
If lesion is identified on CT what should be done
Dexamethasone and refer to neurosurgery
Define idiopathic intracranial HTN (Bening intracranial HTN)
Raised in ICP (above 20mmHg) with no hydrocephalus or mass present
What demographic is IIH more common in
Obese women 15-45 years
Especially if gained weight quickly
What are 3 broad risk factors for IIH
- Pregnant
- Obese
- Medications
What 5 medications increase risk of IIH
- Lithium
- Steroids
- Vitamin A
- GH
- Tetracycline
How does IIH present clinically
- Headache: may be associated with nausea and vomiting
- Visual changes
- CN6 Palsy
What visual changes may occur in IIH
- Enlarged blind spot
- Blurred vision
- Papilloedema
How does CN6 Palsy present
Horizontal diplopia - due to inability to abduct
What will be seen on ophthalmoscopy in IIH
Bilateral papilloedema
What should be ordered in all cases of IIH and why
MRI - Identify and exclude structural lesions
Aside from MRI, what other investigation may be performed in IIH
LP
What will be seen on LP in IIH
Opening pressure of more than 26
What indicates a very raised opening pressure
> 30mmHg
What conservative management is indicated for IIH
Weight Loss
Medication review
What medical management is indicated for IIH
Acetazolamide
Topiramate
Why may topiramate be beneficial
Also helps with weight loss
What surgical management may be indicated for iIH
- Optic nerve sheath decompression
- VP Shunt
Define hydrocephalus
Dilation of ventricles, due to accumulation of CSF
What are the two types of hydrocephalus
- Obstructive (Non-communicating)
2. Non-Obstructive (Communicating)
What is communicating hydrocephalus also know as
Non-obstructive
What causes communicating hydrocephalus
Increase CSF production
Decrease CSF reabsorption
What is obstructive hydrocephalus also known as
Non-Communicating
What is obstructive (non-communicating hydrocephalus)
Obstruction to CSF Flow
What is hydrocephalus ex vacuo stand for
Compensatory enlargement of ventricles secondary to brain atrophy
In communicating hydrocephalus, what can increase CSF production
Chorioid carcinoma
Chorioid papilloma
In communicating hydrocephalus, what are 3 causes of decrease CSF absorption
- Inflammation: eg. meningitis
- Haemorrhage: SAH or IV
- Congenital absece arachnoid villi
Why does SAH and IV Haemorrhage cause decreased absorption of CSF
Leads to fibrosis which can occlude arachnoid villi
In obstructive hydrocephalus, how may causes be divided
Congenital
Acquired
What are two congenital causes of obstructive hydrocephalus
- Dandy-Walker Malformation
- Arnold-Chiari Malformation
What is a dandy walker malformation
Congenital malformation due to failure fourth-ventricle to close
What are 3 acquired causes of obstructive hydrocephalus
- Brain tumour
- SAH or IV Haemorrhage
- Inflammaiton: post-meningitis
Overall, how does hydrocephalus present clinically
Symptoms raised ICP
- Morning Headache
- N+V
- Drop in GCS
- Cushing’s Reflex When Severe
When does the anterior fontanelle close in infants
1-3 years
Explain symptoms raised ICP in children
- As anterior fontanelle has not closed head has room to expand causing MACROCEPHALY
- The open anterior fontanelle may feel tense and BULDGE
- Compression of superior colliculus due to raised ICP causes upward gaze palsy presenting as sun-setting eyes
What are sunsetting eyes
Individual has upward gaze palsy meaning pupils appear as if facing downwards. The lower eyelid may cover half of the pupil. Only sclera can be seen between pupil and upper eyelid
In infants under 6-months, what is used to identify hydrocephalus
US
What is used for children with suspected hydrocephalus
CT or MRI
What will be seen on CT/MRI in obstructive hydrocephalus
Dilation of ventricles superior to the obstruction
What will be seen on CT/MRI in non-obstructive hydrocephalus
Dilation of all ventricles
When should an LP only be performed in hydrocephalus
If communicating (Non-obstructive) hydrocephalus
What is first-line for acute hydrocephalus
External ventricular drain
Drains into bag beside the bed-side
Where is external ventricular drain inserted
Right lateral ventricle
What is long-term management for hydrocephalus
VP Shunt
What is normal pressure hydrocephalus
Communicating hydrocephalus with normal opening pressure
In which age-group does normal pressure hydrocephalus occur
Over 60’s
What is the mnemonic to remember symptoms in normal pressure hydrocephalus
Wet, Wacky, Wobbly
What triad of symptoms occurs in normal pressure hydrocephalus
- Urinary Incontinence
- Ataxia
- Dementia
Why does wet occur
- Dilation of ventricles disrupts the cona radiata causing urinary incontinence
What is wacky section of normal pressure hydrocpephalus
- Dementia
What is wobbly section of normal pressure hydrocephalus
- Ataxia
- Wide based gait with small steps
How will gait appear in normal-pressure hydrocephalus
Wide base, small-steps
How will normal pressure hydrocephalus present on CT or MRI
Enlarged fourth ventricle
What is a arnold-chiari malformation
Herniation cerebellar tonsils, vermis and medulla through foramen magnum
When will arnold-chiari symptoms manifest
Infancy
What does Arnold chair malformation cause
- Obstructive hydrocephalus (due to stenosis cerebral aqueduct)
- Feeding difficulties
- Breathing difficulties
What are Arnold chiari malformations associated with
Myelomeningocele
Syringomyelia