Neurology Flashcards
How are seizures defined?
Transient episode of symptoms due to abnormally excessive or synchronous neuronal activity in the brain
Define epilepsy
Neurological disorder characterised by recurring seizures
At least two unprovoked seizures occurring more than 24 hours apart OR
One unprovoked seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years OR
Diagnosis of an epilepsy syndrome
Define status epilepticus
Prolonged convulsive seizure lasting for 5 minutes or longer, or recurrent seizures one after the other without recovery in between
List causes of epilepsy and risk factors for epilepsy
Structural – stroke, trauma, malformation (genetic or acquired)
Genetic
Infectious – due to infection in which seizures are a core symptom (not seizure due to acute infection e.g., meningitis) e.g., tuberculosis, cerebral malaria, HIV
Metabolic – porphyria, pyridoxine deficiency
Immune – anti-NMDA encephalitis
Risk factors:
Prematurity
Complicated febrile seizures
FHx
Head trauma, infections, traumas
Cerebrovascular disease
Dementia and neurodegenerative disorders
Describe the classification of seizures
By area of onset:
Focal – start in a specific area, in one hemisphere
Generalised – involve both hemispheres
Focal to bilateral – begin in one hemisphere but spread to both
Level of awareness – aware, impaired awareness, loss of consciousness (all generalised)
Motor and non-motor
Specific types:
Generalised tonic-clonic – increased tone then jerking, with tongue biting, incontinence, groaning, irregular breathing
Myoclonic – brief, rapid muscle jerks
Atonic – ‘drop attacks’, brief lapses in muscle tone
Absence – brief episodes, blank, staring into space and then abruptly returns to normal, unaware of surroundings and don’t respond
Describe the rules for driving with epileptic seizures
First seizure:
Can’t drive for at least 6 months, 12 months if high-risk for another seizure
Established epilepsy:
Can drive if 12 months seizure-free, or 6 months if seizure was due to medication change
If seizures only during sleep can drive if only had seizures during sleep for past 3 years
Describe the pharmacological management of epilepsy
Generalised tonic-clonic:
Sodium valproate first line in males or women unable to have children
Lamotrigine or levetiracetam first line for women and girls able to have children, and second line for men
Focal seizures:
Lamotrigine or levetiracetam first line
Second line – carbamazepine
Absence seizures:
Ethosuximide first line
Sodium valproate second line
Myoclonic seizures:
Sodium valproate first line for males or women unable to have children
Levetiracetam first line in women able to have children
Atonic/tonic seizures:
Sodium valproate first line for males and women unable to have children
Lamotrigine for women able to have children
Describe the mechanism of action of anti-epileptic drugs
Sodium valproate – increases GABA activity
Carbamazepine – increases refractory period of sodium channels
Lamotrigine – sodium channel blocker
Levetiracetam – binds to SV2A protein to modulate neurotransmitter release (unknown exact mechanism)
List the major side effects of anti-epileptic drugs
Sodium valproate:
Increased appetite, weight gain
Alopecia, curly regrowth
P450 enzyme inhibitor
Ataxia
Tremor
Hepatitis
Pancreatitis
Thrombocytopaenia
Teratogenic – neural tube defects (do not used in women of childbearing age)
Carbamazepine:
P450 enzyme inducer
Dizziness and ataxia
Leucopaenia, agranulocytosis
SIADH
Visual disturbance – diplopia
Lamotrigine:
Stevens-Johnson syndrome
Which antiepileptic drugs are safe in pregnancy?
Lamotrigine and levetiracetam are safest
How is status epilepticus managed?
A-E assessment
Oxygen
Check BM
IV benzodiazepines – lorazepam or diazepam
(pre-hospital – PR diazepam or buccal midazolam)
Can repeat once after 10-20 minutes
If ongoing can start second-line agent e.g. phenytoin or phenobarbital
If no response within 45 minutes from onset best way to control is with induction of general anaesthesia
Describe the aetiology of cerebrovascular accidents
Ischaemic (85%):
Thrombotic
Embolic – AF
Hypoperfusion – cardiac arrest
Cerebral venous sinus thrombosis – venous congestion causes hypoxia
Haemorrhagic:
Intracerebral
Subarachnoid
Risk factors:
General risk factors for CVD – smoking, obesity, hypertension, diabetes
Embolic – AF, carotid artery disease
Thrombosis – COCP, hereditary thrombophilia, malignancy
Haemorrhagic – AV malformation, anticoagulation, hypertension, trauma
Describe the classification of ischaemic strokes
Bamford/Oxford classification
Total anterior circulation stroke – middle and anterior cerebral arteries, need to have all of:
Unilateral weakness/sensory loss of face, arm and leg
Homonymous hemianopia
Higher cerebral dysfunction – dysphagia, visuospatial disorder
Partial anterior circulation stroke – smaller divisions of anterior circulation (e.g. upper or lower middle cerebral artery), two of:
Unilateral weakness/sensory loss of face, arm and leg
Homonymous hemianopia
Higher cerebral dysfunction – dysphagia, visuospatial disorder
(or higher dysfunction alone)
Posterior circulation stroke – vertebrobasilar arteries (cerebellum and brainstem), one of:
Cranial nerve palsy and contralateral motor/sensory deficit
Bilateral motor/sensory deficit
Conjugate eye movement disorder
Cerebellar dysfunction e.g. vertigo, nystagmus, ataxia
Isolated homonymous hemianopia
Lacunar stroke – small vessel disease, one of:
Pure sensory or pure motor
Sensorimotor
Ataxic hemiparesis
(no higher dysfunction)
Describe the presentation of strokes by vessel affected
Anterior cerebral artery – contralateral hemiparesis and sensory loss, legs affected more than arms
Middle cerebral artery – contralateral hemiparesis and sensory loss, arms affected more than legs, contralateral homonymous hemianopia, aphasia
Posterior cerebral artery – contralateral homonymous hemianopia with macular sparing, visual agnosia
Weber’s syndrome (midbrain branches of posterior cerebral artery) – ipsilateral CN III palsy, contralateral weakness of upper and lower extremity
Posterior inferior cerebellar artery (lateral medullary/Wallenberg syndrome) – ipsilateral facial pain and temperature loss, contralateral limb/torso pain and temperature loss, ataxia, nystagmus
Retinal/ophthalmic artery – amaurosis fugax
Basilar artery – ‘locked-in’ syndrome
Describe the initial assessment of suspected stroke
Exclude hypoglycaemia
ROSIER score – stroke likely if >0
Non-contrast CT head 1st line investigation (exclude haemorrhage)
Investigations – ECG, U+Es, LFTs, cholesterol, FBC, ESR, coagulation
Swallow assessment within 4 hours – before oral medications, fluid, diet
Describe the presentation of haemorrhagic stroke compared with ischaemic stroke
Abrupt onset symptoms and decompensation
Reduced level of consciousness
Headache
Nausea and vomiting
Seizures
Describe the initial management of strokes
O2 as required
Withhold platelets and anticoagulants until CT excluded haemorrhage
If BM low correct, if high can give insulin but avoid hypoglycaemia
IVF as required
Haemorrhagic stroke excluded – give aspirin 300mg orally (if swallow safe) or rectally ASAP
If presenting less than 4.5 hours since symptom onset, symptoms still present and haemorrhage ruled out may be suitable for thrombolysis with alteplase
If presenting within 6 hours of symptom onset offer thrombectomy for confirmed occlusion of proximal anterior circulation on CTA or MRA (with thrombolysis)
Can also give if known to be well between 6-24 hours previously if confirmed proximal anterior circulation occlusion and potential to salvage brain tissue (on CT perfusion or diffusion-weighted MRI)
If not suitable for either give 300mg aspirin for 14 days then 75mg once daily
Aspirin and clopidogrel given for non-cardioembolic minor ischaemic stroke or high risk TIA (ABCD >4), for 21 days then clopidogrel 75mg long term
If haemorrhage on CT – check coagulation screen, stop anticoagulants (consider reversal), neurosurgery referral?
List indications for urgent CT in suspected stroke
Reduced GCS or coma
On anticoagulants
Brainstem signs, bilateral signs, ‘locked-in’
Cerebellar stroke signs with headache or raised ICP symptoms
Severe headache
Stuttering onset
Immunocompromised
Unexplained fever
Signs of raised ICP
List contraindications to thrombolysis for management of stroke
Define TIA and stroke
Transient ischaemic attack – transient episode (less than 24 hours) of neurologic dysfunction caused by focal brain, spinal cord or retinal ischaemia, without acute infarction (no longer purely time based, even short ischaemia can result in pathological changes)
Stroke – clinical syndrome of presumed vascular origin characterised by rapidly developing signs of focal or global disturbance of cerebral functions which persist (longer than 24 hours) or leads to death
Describe initial assessment and management of TIA
Immediate management:
No longer use ABCD2 score
Give aspirin 300mg immediately, unless patient has bleeding disorder or is taking anticoagulant, patient is already taking low-dose aspirin regularly (continue this until reviewed by specialist) or aspirin is contraindicated
Specialist review:
If more than one TIA (crescendo TIA) or suspected cardioembolic source or severe carotid stenosis discuss need for admission or observation urgently with stroke specialist
If suspected TIA in past 7 days – assessment within 24 hours by specialist stroke physician
If suspected TIA over a week ago – specialist assessment within 7 days
CT brain not recommended unless suspicion of another diagnosis
MRI (including diffusion weighted and blood-sensitive sequences) preferred, on same day as specialist assessment
Urgent carotid doppler (unless not a surgical candidate)
Driving rules for TIA/stroke
TIA
Don’t drive until seen by specialist
1 TIA – don’t drive for 1 month, no need to inform DVLA
Multiple TIAs – don’t drive for 3 months, need to notify DVLA
Stroke
Don’t drive for at least 1 month, may not need to inform DVLA
Can start driving after 1 month if made adequate clinical recovery, only need to inform DVLA if residual neurological deficit (particularly visual field defect, cognitive defect, impaired limb function)
Describe secondary prevention for TIA/stroke
Lifestyle modification
Ischaemic stroke/TIA:
Clopidogrel first-line (without AF)
Aspirin and modified release dipyridamole if clopidogrel contraindicated or not tolerated
Given long-term
High-intensity statin (e.g. atorvastatin)
Anti-hypertensives – target SBP less than 130mmHg (or 140-150 if severe bilateral carotid artery stenosis)
Anticoagulation in AF – DOAC (non-valvular) or warfarin (valvular)
Optimise management of comorbidities e.g. diabetes
Carotid artery stenosis:
Carotid artery endarterectomy recommended if patient has had stroke or TIA in carotid territory (extracranial internal carotid, ophthalmic artery, middle cerebral artery or anterior cerebral artery) and is not severely disabled
Considered if stenosis more than 70% according to European trial or 50% according to North American trial
Describe the cause and presentation of a subarachnoid haemorrhage
Causes:
Traumatic
Spontaneous –
Intracranial aneurysm (85%), associated with hypertension, PKD, Ehlers-Danlos, coarctation of the aorta
AV malformations
Pituitary apoplexy
Mycotic (infective) aneurysm
‘Thunderclap’ headache – acute onset, reaches peak intensity within seconds-minutes, occipital, severe (worst headache of life)
Nausea and vomiting
Photophobia
Neurological symptoms – dysphasia, weakness, visual disturbance, seizures
Reduced consciousness
Neck stiffness
Kernig’s sign – pain with passive knee extension when lying supine and hips and knees flexed
May have ECG changes e.g. ST elevation
How are subarachnoid haemorrhages assessed initially?
Investigation:
Non-contrast CT head first-line – hyperdense blood in basal cisterns, sulci, ventricular system
If CT head done within 6 hours of symptom onset and is normal, consider alternative diagnosis
If CT head done more than 6 hours after symptom onset and is normal – do an LP at least 12 hours after symptom onset
LP – xanthochromia, normal/raised opening pressure
If CT shows evidence of SAH immediate referral to neurosurgery
Further investigation:
CT angiogram to identify vascular lesion +/- digital subtraction angiogram (catheter angiogram)
Describe management of confirmed subarachnoid haemorrhage
Supportive:
Bed rest
Analgesia
VTE prophylaxis
Discontinuation of anti-thrombotics (reversal or anticoagulation if present)
Antiepileptics for seizures
Nimodipine – prevent vasospasm
Aneurysms are at risk of rebleeding, intervention within 24 hours – interventional radiology coiling (minority get craniotomy and clipping)
