Raise ICP, SOLs and trauma Flashcards by Joanna Mitchell

What is the normal volume of CSF?

120-150ml

500ml a day

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What produces CSF?

Choroid plexus in the lateral and 4th ventricles of the brain

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What absorbs CSF?

Arachnoid granulations

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What do lymphocyres in the CSF suggest?

Infection; viral or fungal
Autoimmune infection
Inflammation

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What do neutrophils in the CSF suggest?

Bacterial meningitis

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What is the definition of hydrocephalus?

Accumulation of excessive CSF within the ventricular system of the brain

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What can cause hydrocephalus?

Obstruction to flow: inflammation, pus, tumours
Decreased reabsorption; post SAH, meningitis
Overproduction; very rare cause due to choroid plexus tumour

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What is non-communicating hydrocephalus?

Obstruction to flow of CSF occuring within the ventricular system

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What is communicating hydrocephalus?

Obstruction to flow of CSF outside of the ventricular system e.g. in subarachnoid space or at the arachnoid granulations

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What occurs if hydrocephalus occurs before the closure of the cranial sutures?

Cranial enlargement occurs

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What occurs if hydrocephalus occurs after the closure of the cranial sutures?

Expansion of the ventricles with an increase in intracranial pressure

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What is hydrocephalus ex vacuo?

Dilation of the ventricular system and an increase in compensatory CSF volume secondary to the loss of brain parenchyma for example in alzheimer’s disease

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What are the causes of increased ICP?

Hydrocephalus 
SOL 
Diffuse lesion in brain e.g. oedema 
Increased venous volume
Physiological; hypoxia, hypercapnia, pain

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What are the consequences of raised ICP?

Intracranial shifts and herniations
Midline shift
Distortion and pressure on CNs and vital neurological centres
Impaired blood flow
Reduced level of consciousness

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How is cerebral perfusion pressure calculated?

MAP - ICP; therefore ICP is too high, it will reduce blood flow

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What are the 4 types of shifts and herniations within the brain?

Subfalcine
Tentorial
Cerebellar
Transcalvarial

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What is a subfalcine herniation?

Unilateral or asymmetrical expansion of the cerebral hemisphere which displace the cingulate gyrus underneath the falx cerebri

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What does a subfalcine herniation result in?

Compression of the anterior cerebral artery resulting in weakness and/or sensory loss on the contralateral side

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What is a tentorial herniation?

Medial aspect of the temporal lobe (uncus) herniates over the tentorium cerebellar

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What will a tentorial herniation result in?

Compression of the ipsilateral CN3; resulting in a blown pupil with impairment of ocular movement on the side of the lesion

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What is a tonsillar herniation?

Displacement of the tonsillar cerebellum through the foramen magnum

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What will a tonsillar herniation result in?

Compression of the respiratory centers of the medulla oblongata

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What is a transcalvarial herniation?

Brain herniating through any defect in the skull e.g. fracture

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What are the clinical signs of an increased ICP?

Papilloedema
Headache
N+V
Neck stiffness

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What are the different types of SOLs?

Tumours; primary brain tumours, mets Abscess; single/multiple Haematomas Localised brain swelling; swelling and oedema around cerebral infarct

What are the Si/Sy of brain tumours?

Sy: focal, headache, vomiting, seizures, visual disturbances | Signs; focal deficit, papilloedema

What is the difference in location of brain tumours between children and adults?

Children; 70% below tentorium cerebelli | Adults; 70% above tentorium cerebelli

What common cancers will metastasize to the brain?

Breast, bronchus, kidney, thyroid, colon and melanomas

What is used to grade primary brain tumours?

Mitoses Neovascularization Necrosis Atypia, cellularity

What are the common malignant primary intracranial tumours?

``` Astrocytoma Oligodendroglioma Ependymoma Medulloblastoma Haemangioblastoma Lymphoma Pineal ```

What are the common benign primary brain tumours?

Meningioma Schwannoma Craniopharyngioma Pituitary adenoma

What is the commonest brain tumour in children?

Medulloblastoma | Astrocytoma; pilocytic

Describe a pilocytic grade 1 astrocytoma

Common in children Benign behaving Long hair like processes Cystic area

Describe a grade 2; low grade astrocytoma

Nuclear atypia

Describe a grade 3 anaplastic astrocytoma

Greater nuclear atypia | Mitotic activity

Describe a grade 4 glioblastoma

Extreme nuclear atypia Mitotic activity Necrosis Neovascularization

What can be seen histologically from a glioblastoma?

Anaplastic Proliferation; numerous mitotic figures Necrosis with assoc nuclear palisading Neoangiogenesis

Describe a medulloblastoma?

20% of paeds CNS neoplasms Poorly differentiated/embryonal Occurs in midline of cerebellum and can easily disrupt CSF flow resulting in hydrocephalus

How are medulloblastomas treated?

Radiotherapy

What can result in a single brain abscess?

Local extension from: Mastoditis, chronic otitis media, paranasal sinusitis, nasal facial and dental infection Direct implantation: skull fracture

What can result in multiple brain abscesses?

Haematogenous spread; bronchopneumonia, bacterial endocarditis, bronchiectasis, lung abscesses, congenital heart disease (left to right shunt) PWID

Where will multiple brain abscesses occur?

Grey and white matter boundary

What will occur with brain abscesses?

``` Central necrosis Oedema Fibrous capsule Hypoxia and ischaemia Excitotoxic injury ```

What are the symptoms of a brain abscess?

Fever | Increased ICP

How are brain abscesses diagnosed?

CT or MRI

How are abscesses treated?

Aspiration for culture and treatement

What is bacterial meningitis?

Inflammation of the leptomeninges and SF within the subarachnoid space

What can be seen on an LP from bacterial meningitis?

Abundant polymorphs and neutrophils | Decreased glucose

What can arachnoiditis result in?

Lack of CSF absorption Hydrocephalus Increased ICP

What organism causes bacterial meningitis in neonates?

E.coli; gram negative rods

What organism causes bacterial meningitis in infants and children?

Haemophilus influenzae; gram negative cocco-bacilli

What organism causes bacterial meningitis in adolescents and young adults?

Neisseria meningitis; gram negative diplococci

What organism causes bacterial meningitis in older adults or children?

Streptococcus pneumoniae; gram positive cocci in chains

What organism causes bacterial meningitis in older adults and those immunocompromised?

Listeria monocytoggene; gram positive rod

How can head trauma be classified?

Missile or non-missile (penetrating or blunt)

What can result from head trauma?

Skull # | Parenchymal and vascular injuries

What will a penetrating head trauma result in?

Focal damage Lacerations in region of brain damage Haemorrhage

What does the severity of a blunt injury rely on?

Initial velocity and the contact time; the smaller the contact time, the larger the force

What are causes of blunt head injuries?

RTCs Falls Assaults Alcohol related injuries

What will the primary (impact) injury do?

Injury to neurones Irreversible Preventative measures; wearing a helmet and seat belts for example

What are the secondary head injuries?

Haemorrhage Oedema Potentially treatable

What is the clinical hallmark of head injuries?

Immediate change in conscious level is dependent on the scale of neuronal damage

What are examples of primary head injuries?

``` Scalp lesions Skull fractures Surface contusions and lacerations Diffuse axonal injury Diffuse vascular injury Petechial haemorrhages ```

What are the 3 types of skull fractures?

Linear Compound Depressed

What is a linear skull#?

Straight sharp fracture line, that may cross sutures

What is a compound skull#

Assoc with full thickness scalp lacerations

Are base of skull fractures open or closed?

ALWAYS consider compound because there is a high change that base of skull fractures will lacerate the paranasal sinuses giving bacteria a route for entrance to the cranium

What is a contra-coup injury?

Injury to the non-impact side diametrically opposite the point of impact Occurs as a rebound

What is a diffuse axonal injury?

Occurs at the moment of injury due to shearing strains on the axonal bulbs Affects central areas

What will a diffuse axonal injury lead to?

Reduced consciousness and coma | Lead to vegetative state

What are secondary head injuries?

``` Intracranial haemorrhage Reduced brain flow Hypoxic brain damage Excitotoxicity Oedema Raised ICP Infection ```

What oedema is assoc with trauma?

Vasogenic oedema

What are the percentages surrounding traumatic intracranial haematoma?

20% are extradural | 80% are intradural

What does a traumatic extradural haematoma result from?

Fracture of pterion rupturing the middle meningeal artery

What causes an acute SAH?

Disruption of bridging veins that extend from the surface of the brain into the subdural space

What are chronic subdural haematomas assoc with?

Brain atrophy

What is a chronic subdural haematoma composed of?

Liquefied blood/ yellow tinged fluid separated from inner surface of dura mater and underlying brain by neomambrane

Raise ICP, SOLs and trauma Flashcards

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