Central nervous system Flashcards
What is a traumatic brain injury?
- External force causes brain dysfunction
- Caused by violent blow or penetrating injury
- Varies in severity
- Mild: temporary dysfunction
- Concussion
- More serious: permanent brain damage or death
- Cerebral oedema / haemorrhage
List 3 TBI causes
- Motor vehicle, bike or skateboarding accident
- Playing sports: contact sport
- Recreation activities
- Falls
- Assault: shaking, hitting, or throwing
- Exposure to blasts
Who are at greater risk of getting a TBI?
- Young males
- Elderly
- Children
- ATSI
What is a concussion?
Most common form of traumatic brain injury
What are the 3 types of concussions?
- Mild: no loss of consciousness, symptoms last less than 15 min
- Moderate: no loss of consciousness, symptoms last longer than 15 min
- Severe: Loss of consciousness
List 5 symptoms of a concussion
- Confusion or feeling dazed
- Clumsiness
- Slurred speech
- Nausea or vomiting
- Headache
- Balance problems or dizziness
- Blurred vision
- Sensitivity to light
- Sensitivity to noise
- Sluggishness
- Ringing in ears
- Behaviour or personality changes
- Concentration difficulties
- Memory loss
How do they diagnose TBIs?
- Physical examination
- CT: primary imaging modality, moderate to severe head injuries, highly accurate and sensitive
- MRI: Further investigation subtle injury, moderate injuries
- NM: Brain death studies, severe injuries
- Electroencephalogram: EEG
What are the 4 types of serious TBI?
- Cerebral oedema
- Cerebral contusion
- Cerebral haemorrhage: epidural, subdural, subarachnoid, intracerebral, diffuse axonal injury
- Skull fracture
What is cerebral oedema?
- Decreasing level of consciousness – unconscious
- Swelling of brain cells causing increase brain water content
- CT initial imaging modality
- Scans can initially be normal
- Loss of grey – white matter differentiation
- Hypodense brain parenchyma
- Effaced sulci
- Supra-sellar cistern obliteration (uncal herniation)
- Cerebellar tonsil herniation
- Reduced brain activity
What is a cerebral contusion?
- Caused by movement of brain within the skull
- Brain injury occurs when brain hits rough surfaces e.g. frontal, anterior temporal regions
- CT usually modality of 1st contact
- Areas of low density oedema
- Multiple small high density areas: haemorrhage
- MRI often used to further evaluate
What is a diffuse axonal injury?
- Shearing of brains nerve fibres
- Caused by rotational acceleration and deceleration
- Commonly associated with high speed MVA
- Loss of consciousness
- Pt in vegetative state but death uncommon
- Swelling of brain greatest risk
- Difficult to diagnose on imaging alone
- CT & MRI can be utilised
What is an epidural haematoma?
- Caused by structural disruption of the dura and blood vessels
- Trauma is the typical cause of EDH. The trauma frequently is a blunt impact to the head from an assault, fall, or other accident
- Most commonly a blow to the temporal bone rupturing middle meningeal artery
- Commonly associated with fractures of the calvarium
- Causes mass effect and acute neurological symptoms
- Biconvex or lens shaped
- Acute stage hyper dense on CT
- Rarely has non traumatic origin
- Requires emergency decompression surgery
What is a subdural haematoma?
- Haemorrhage between Dura and Arachnoid membrane
- Most common form of traumatic intracranial mass lesion
- Can be caused by major and minor head trauma
- Caused by high speed acceleration and deceleration of the brain
- Causes tears in blood vessels
- Elderly on anticoagulants susceptible
- 2-3x more common in men
- Minor haemorrhage treated conservatively as blood naturally reabsorbed
- Major haemorrhage surgical decompression
- Categorised as acute, sub-acute and chronic
What is a subarachnoid haematoma?
- Pt presents with severe headache, vomiting, blurred vision, stiff neck
- Haemorrhage between arachnoid and pia mater spaces
- Most commonly caused by trauma but can be spontaneous
- Usually associated with aneurysm rupture
- Can be pre-existing or created by trauma
- Traumatic aneurysm associated with base of skull fractures
- Aneurysm risk: Atherosclerosis, Hypertension, Advancing age, Smokers
- More common in females 3:2
- Can lead to increased ICP requiring surgical intervention
- Primary diagnosis CT and lumbar puncture
- Cerebral angiography can be used to find location of haemorrhage
- Surgical repair of vessel may be necessary
What is an intercranial haemorrhage?
- Haemorrhage into brain parenchyma
- Caused by shearing forces to intraparenchymal arteries
- Traumatic and non-traumatic origin
- Traumatic causes can be penetrating or non-penetrating
- Symptoms include headache, weakness, confusion, and paralysis
- Serious condition, causes rapid increase in ICP
- Major haemorrhage surgical decompression
What is an intraventricular haemorrhage?
- Haemorrhage into the ventricles of the brain
- Associated with subarachnoid and intracerebral haemorrhage
- Increases morbidity and mortality rates of patients
- Usually associated with dangerously raised ICP
What are some treatment options for TBI?
- Treatment will vary with severity of injury
- Usually conservative in nature
- Monitor neurological signs
- Monitor intracranial pressure (ICP)
- Follow up imaging
- Medical treatment to lower ICP (e.g. osmotherapy, diuretics, corticosteroids)
- Surgical decompression if ICP becomes unmanageable
What is cerebrovascular disease?
Stroke
list three epidemiological facts regarding stroke
- Second most common cause of death in the World
- Kills more women than breast cancer and more men than prostate cancer
- Leading cause of adult disability
- In Australia 56,000 new and recurrent strokes this year– that is one stroke every nine minutes
- 30% stroke survivors under 65
- 65% of stroke survivors suffer a disability which impedes their ability to carry out daily living activities unassisted
- The financial cost of stroke in Australia is estimated to be $5 billion each year
- More than 80% of strokes can be prevented
What is a transient ischemic attack?
- partial occlusion
- ‘angina of the brain’
- Focal neurological event lasting <24 hours
- Focal loss of central nervous function due to decreased blood flow to part of the brain
- precursor for CVA
Define cerebrovascular accident
Sudden and severe focal loss of Central Nervous System function due to decreased blood flow to focal region of the brain
Name 5 signs/symptoms of CVA
- Abrupt onset of hemiparesis, monoparesis, or (rarely) quadriparesis
- Hemisensory deficits
- Monocular or binocular visual loss
- Visual field deficits
- Diplopia
- Dysarthria (unable to articulate speech)
- Facial droop
- Ataxia (lack of muscle control)
- Vertigo (rarely in isolation)
- Nystagmus (involuntary eye movement)
- Aphasia (unable to understand or produce speech)
- Sudden decrease in level of consciousness
How do they diagnose CVA?
- medical history/ risk factors check
- physical examination: airway and breathing, reflexes, muscle strength etc., BP, listen to heart
- Blood tests
- ECG
- imaging
What are the non-modifiable risk factors for CVA
age race sex (F) history of migraines fibromuscular dysplasia fam history of stroke or TIA
what are 5 modifiable risk factors for CVA
hypertension diabetes cardiac disease TIA carotid stenosis hypercholesterolemia alcohol and drug use obesity oral contraceptive
What is the pathophysiology for ischaemic stroke
- acute occlusion intracranial vessel
- focal reduction in cerebral blood flow (collaterals)
- ischaemic core or ischaemic penumbra
- cell death and infarction of tissues
- haemorrhagic transformation or cerebral oedema
- patient death
what are the 3 stages/phases of an ischaemic stroke?
acute phase/stage (0-24/48 hours)
subacute phase/stage (24/48 + hours)
chronic phase/stage (4 to 6+ weeks)
what are the types of ischaemic stroke
large vessel
small vessel
thrombotic
embolic
what happens in a small vessel ischaemic attack?
- Occlusion of small sub-cortical non-branching arteries (<15-20mm)
- Occur most frequently in the basal ganglia and in the internal capsule, thalamus, corona radiata, and pons
- Accounts for around 20% of ischaemic strokes
- Symptomatic or non-symptomatic
- Higher risk of more serious large vessel stroke
what happens in a large vessel ischaemic attack
Occlusion of large artery in the brain
Thrombotic origin most common
MCA most commonly occluded major artery
Clinical emergency