Clinical neuroscience Flashcards
What is status epilepticus?
medical emergency which is defined as a seizure lasting > 5 mins or more than 3 seizures in 1 hour without regaining consciousness
What is the first aid management for seizures?
- Asses - remove objects that can cause injury
- Cushion - for the head
- Time - time the duration
- Identify - medical bracelet and cards
- Over - when the seizure is over roll them into recovery position
- Never - put anything in their mouth or try to restrain them
What is the A-E approach for?
secure airway
high flow O2
gain IV access and take blood
check blood glucose
what class of drugs are used in seizures?
benzodiazepines
which benzodiazepine is used in the hospital setting?
IV lorazepam
which benzodiazepine is used in the community?
PR diazepam
buccal midazolam
what do you give to a patient in established status epilepticus?
valproate
what do you give to a patient in refractory status epilepticus (45 mins after onset)?
induction of general anaesthesia
what are blackouts?
describe the event of temporarily losing consciousness and muscle strength as a result of disrupted blood flow to the brain, if a patient is standing up this leads to a fall
Also referred to as vasovagal episodes, fainting, syncope
what are the features of syncope?
- Prolonged upright position before the event
- Lightheaded before the event
- Sweating before the event
- Blurring or clouding of vision before the event
- Reduced tone during the episode
- Return of consciousness shortly after falling
- No prolonged post-ictal period
what are the features of seizure?
- Epilepsy Aura (smells, tastes or deja vu) before the event
- Head turning or abnormal limb positions
- Tonic Clonic Activity
- Tongue Biting
- Cyanosis
- Lasts more than 5 minutes
- Prolonged post-ictal period
what are the 2 categories of blackouts?
primary syncope (simple faint) secondary syncope (underlying disease)
what are the causes of primary syncope?
- dehydration
- missed meals
- standing in warm environment
- vasovagal response to stimuli (pain, sight of blood)
what are the causes of secondary syncope?
- Anaemia
- Hypoglycaemia
- Dehydration
- Severe Haemorrhage
- Infection
- Anaphylaxis
- Arrythmias
- Valvular heart disease (aortic stenosis)
- Hypertrophic obstructive cardiomyopathy
- PE
what are the clinical features of someone who has experienced syncope (blackout)?
- prodrome - warning that they will faint (pre-syncope)
- hot or clammy
- sweaty
- heavy
- dizzy and lightheaded
- blurry vision
- headache
- groggy when regaining consciousness but no confusion
what causes a blackout/syncope
due to problems in the Autonomic Nervous System ability to regulate blood flow to the brain
vagus nerve receives a strong stimulus causes a stimulation of the parasympathetic nervous system
results in decreased blood pressure and cardiac output, leading to reduced blood pressure
reduced perfusion of the brain, leading a patient to lose consciousness
investigations for blackouts/syncope
- Bedside - obs, lying and standing BP, dehydration, ECG (arrhythmia and long QT)
- Bloods - FBC (anaemia), WCC/CRP (infection), glucose (hypoglycaemia), electrolytes (deranged)
- 24 hour ECG if paroxysmal arrhythmia suspected
- tilt table test
what is a TIA?
Brief period of neurological deficit due to a vascular cause, typically lasting less than an hour. A transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction (tissue-based definition). Often called mini-stroke. No evidence of ischaemia on MRI.
clinical features of TIA
- similar to stroke - sudden onset, resolves within 1 hour
- unilateral weakness or sensory loss
- aphasia or dysarthria (disordered speech)
- ataxia, vertigo, or loss of balance
- visual problems - loss of vision in one eye, diplopia, homonymous hemianopia (only see one half of the world from each eye)
pathophysiology of TIA
- temporary reductions in cerebral blood flow result in ischaemia of cerebral tissue, leading to tissue dysfunction which presents the symptoms of a stroke
- When blood flow is restored to the brain the symptoms disappear -TIA can be thought of as angina of the brain
what investigations are ordered for TIA?
- MRI of head (not CT) - look for territory of ischaemia
- Carotid imaging - carotid US/doppler to look for atherosclerosis
what drug do we give to patients who have had a suspected TIA?
300 mg aspirin
what are the 2 types of stroke?
ischaemic and haemorrhagic
what is an ischaemic stroke?
caused by blockages in arteries, leading to reduced perfusion to brain tissue that results in its ischaemia and infarction, which can lead to necrosis
risk factors for ischaemic stroke
increased atherosclerosis -existing CVD - previous stroke or TIA CAD - hypertension - diabetes - smoking - alcohol
increased blood coagulation
- AF
- vasculitis
- thrombophilia
- combined contraceptive pill
differentials for ischaemic stroke
head injury
hypoglycaemia
intracranial tumour
wernicke’s encephalopathy
causes of cerebral infarction (ischaemic stroke)
- reduced blood supply to brain
- thrombus/embolus formation - AF
- atherosclerosis
clinical presentation of stroke in anterior cerebral artery
sudden onset weakness and numbness of ipsilateral leg
clinical presentation of stroke in middle cerebral artery
- weakness/numbness in hands and arms
- weakness/numbness in face - droop
- speech changes
clinical presentation of stroke in posterior cerebral artery
- visual disturbances
- motor dysregulation (tremor and abnormal gait)
clinical presentation of lacunar stroke
weakness of entire side of body
what are the 3 types of ischaemic stroke
thombotic
embolic
hypoxic
how does an ischaemic stroke happen
result of an blood clot (embolism or thrombus) causing occlusion of a cerebral artery
leads to reduced blood flow of cerebral tissue, leading to it’s ischaemia and infarction
without oxygen the brain tissue cannot generate ATP
neuronal pumps unable to maintain ion gradients leading to sodium remaining in neurons
leads to continual depolarisation which results in large scale glutamate release which is neurotoxic in large concentrations and thus leads to neuronal death
results in cerebral swelling as water is drawn into neurons as a result of their increased osmolarity
leads to raised ICP
in ischaemic stroke, what neurotransmittter is released in large concentrations and leads to neuronal death
glutamate (due to sodium remaining in neurones)
investigations for ischaemic stroke
- bedside - Rosier tool for stroke recognition in ED
- blood sugar - check for hypoglycaemia
- ECG (arrhythmia, AF)
- echocardiogram
- thrombophilia screen
- CT head - shows as an area of low density, no bright white areas (blood), therefore thrombolysis is needed
- MRI NOT USED
management of ischaemic stroke (cerebral infarction)
- Send to specialist stroke centre
- 300mg aspirin for 3 weeks
- thrombolysis - alteplase to degrade clot (must do CT prior)
what is altepase?
tissue plasminogen activator - activates plasminogen to break down clots
what is intracranial haemorrhage and what are the 4 types?
Intracranial haemorrhage is bleeding within the skull.
There are 4 broad types of intracranial haemorrhage: epidural subdural subarachnoid intraparenchymal (intracerebral)
what is an epidural/extradural haemorrhage?
rupture of the Middle Meningeal Artery causing bleeding between the skull and outside of the dura mater. This rupture is typically caused by a fractured temporal or parietal bone. This bleeding leads to the formation of a haematoma which can compress the brain.
what is the most common cause of extradural haemorrhage?
damage at the pterion
middle meningeal artery lies beneath
lateral blow to the head
why is extradural haemorrhage so dangerous to clinicians?
- talk and die syndrome
- lateral blow to head - lose consciousness
- patient appears well with no neuro sx
- however, can undergo rapid neuro decline as haematoma compresses intracranial contents as it increases in size
what is the clinical presentation of a rapid neuro decline in extradural haemorrhage
- Severe Headache
- Vomiting
- Confusion
- Seizures
- Pupil Dilation
- Reduced GCS
- Coma
what are the investigation for extradural haemorrhage
- bedside - monitor GCS
- bloods - FBCs (transfusion), clotting
- immediate CT head
what investigation must you not do in a patient with suspected extradural haemorrhage
lumbar puncture
how does an extradural haematoma appear on CT head
lemon shaped
what is the surgical management for extradural haematoma?
Surgical evacuation of the clot and ligation of the bleeding vessel
what are the layers and spaces of the brain/meninges
skull epidural space dura mater subdural space arachnoid mater subarachnoid space pia mater
what is a subdural haematoma?
This occurs when there is a bleed between the Dura Mater and Arachnoid Mater, causing blood to accumulate underneath the dura.
risk factors for subdural haemorrhage
- Elderly - Cerebral Atrophy, making the bridging vessels more likely to rupture due to more movement
- Alcoholics - Cerebral Atrophy, making the bridging vessels more likely to rupture due to more movement
- Anticoagulation - Increases the risk of bleed, an elderly person on anticoagulants is therefore at a higher risk of bleeding
what ruptures in a subdural haematoma
bridging veins between dura and arachnoid
clinical features of subdural haemorrhage
- Sx
- Fluctuating Consciousness
- Sleepiness
- Headache
- Unsteadiness
- Vomiting (Raised ICP)
- signs
- raised ICP
- signs of head trauma or injury
pathophys of subdural haemorrhage
- The bleeding underneath the dura causes a haematoma to form which compresses the brain, leading to it’s dysfunction.
- This causes a gradual rise in ICP, which can eventually lead to herniation and coning if left untreated.
investigation for suspected dural haemorrhage
CT head
what would a CT head scan show for a patient with subdural haemorrhage
sickle/banana shaped haematoma - not restricted by suture lines of dura
what colour do acute vs chronic bleeds appear on CT
acute bleeds brighter
management for subdural haematoma
1st Line - Burr Hole Craniostomy allows for irrigaiton/evacuation of the haematoma, reducing ICP
2nd Line - Craniotomy, allowing removal of the haematoma
