Seizures Flashcards
What is a seizure?
A period when neurons are synchronously active when they shouldn’t be
- can be due to increased excitation or decreased inhibition
Discuss over excitation in epilepsy
Patients with epilepsy: long acting NMDA receptors – Ca2+ entry and depolarization
Discuss too little inhibition in epilepsy
Patients with epilepsy can have dysfunctional GABA receptors
- normally cause ion channels to open that allows Cl- influx
Discuss focal seizures
Focal aware (simple partial)
- small area of brain
- strange sensations
- jerking
- patient aware and remembers
Focal impaired awareness (complex partial)
- may not remember
*focal seizures can become generalised – termed secondary generalised
Discuss generalised seizures
- Tonic: stiff, flexed muscles, patient falls back
- Atonic: floppy, patient falls forward
- Clonic: violent convulsions
- Tonic clonic: most common
- Myoclonic: short muscle twitches
- Absence: loss and gain of consciousness with little outward sign
What is status epilepticus?
Seizure lasting >5mins
- usually tonic clonic
*treated with benzos to increase GABA transmission
What would the consequences be in a patient were to have a focal epileptic seizure in their frontal lobes?
- Bladder incontinence
- Disinhibition
- Expressive aphasia
- Dyspraxia
What would the consequences be in a patient were to have a focal epileptic seizure in their parietal lobes?
- Sensory disturbance
- Paresthesia (abnormal sensation)
e. g. warmth up one side of body
What would the consequences be in a patient were to have a focal epileptic seizure in their temporal lobes?
- Odd smell
- auditory/ visual hallucinations
- pallor, flushing, HR changes
- fidgeting, lip smacking
- emotional changes
- repetitive speech or speech arrest
What would the consequences be in a patient were to have a focal epileptic seizure in their occipital lobes?
Swirly multicoloured visual disturbance
Discuss pharmacology of epilepsy
- Diazepam: GABA receptor agonist
- Carbamazepine: anticonvulsant Na+ channel blocker
- Phenytoin: Na+ channel blocker - DO NOT GIVE FOR ABSENCE SEIZURES partial absence seizues
- Sodium valproate: Na+ channel blocker and GABA agonist
What is syncope?
Syncope is the commonest cause of episodes of loss of awareness. Simple faints or vasovagal syncopal attacks can usually be related to identifiable precipitants. Most often they occur on getting up quickly, or standing for prolonged periods, particularly if associated with peripheral vasodilation (e.g. during hot, stuffy weather, crowded trains or rooms, or are related to drug or alcohol use).
What is non-epileptic attack disorder (NEAD)
Non-epileptic attack disorder, previously known as pseudoseizures typically gives rise episodes of two broad types:
(a) attacks involving motor phenomena
(b) attacks of lying motionless.
Psychogenic nonepileptic seizures
AKA pseudoseizures
Features
- Pelvic thrusting
- Family member with epilepsy
- Crying after seizure
- Don’t occur when alone
- Gradual onset
Features favouring true epileptic seizures
- Tongue biting
- Raised serum prolactin
What are seizures?
Spontaneous, episodic, abnormal discharges of electrical activity in the brain
Epidemiology of epilepsy
- 0.5-1% prevalence in UK
- 450,000 people in UK
- 30,000 new diagnoses/ year
Peak in first presentations in children due to primary idiopathic epilepsies and developmental anomalies
Second peak in elderly due to acquired brain diseases e.g. stroke and dementia
Provoked vs unprovoked
- Unprovoked: spontaneous
- Provoked: can provoke a normal brain to have a seizure e.g. alcohol, electrolyte disturbance, recreational drugs
Risk factors causing predisposition for epilepsy
- Prematurity
- Complicated febrile seizures
- Genetic condition known to be associated with epilepsy e.g. tuberous sclerosis or neurofibromatosis
- Brain development malformations
- Family hx
- Head trauma, infections (meningitis, encephalitis), tumours
- Comorbidities e.g. cerebrovascular disease
- Dementia and neurodegen
- Recreational drugs or alcohol withdrawal
- Medication e.g. clozapine
- Electrolyte imbalances: hyponatremia is the most common cause as well as hypoglycaemia - basically any electrolyte derangement can precipitate a seizure
Assessing a patient presenting with first seizure
Ask about risk factors
- What happened before, during and after seizure
- Any aura before seizure - can help pinpoint where seizure originated depending on symptoms
- Any triggers - sleep deprivation, light, alcohol
- Specifics of the seizure
- Short lived, abrupt, generalised muscle stiffness + rapid recovery - suggests tonic seizure
- Generalised muscle stiffening + rhythmic jerking + urinary incontinence + tongue biting - suggests tonic clonic seizure
- Behavioural arrest - absence seizure
- Sudden onset loss of muscle tone - suggests atonic seizure
- Brief, shock like, involuntary single or multiple jerks - suggestive of myoclonic seizure
- Any post-ictal phenomena e.g. drowsiness, headaches, amnesia or confusion (these usually only occur after generalised tonic ± clonic seizures
- Physical examination
- Cardiac, neurological and mental state exam
- Developmental exam if appropriate
- Examine oral mucosa for tongue biting
- Identify any injuries sustained during attack
Baseline tests
- Bloods: FBC, U&E, LFT, glucose and calcium
- 12 lead ECG
Investigations following seizure
- Bloods: U&Es to detect any abnormalities - most commonly associated with seizures in hyponatremia
-
EEG: performed to support diagnosis of epilepsy in children and young people and adults, not performed if suspecting syncope due to high false positive rate
- Not used in isolation to make a diagnosis of epilepsy
- Can be used to determine seizure type
- During EEG seizure may be stimulated by flashing lights or hyperventilation
Neuroimaging
- To identify structural abnormalities that may cause certain types of epilepsy, MRI is investigation of choice
- Particularly important in those who develop epilepsy <2yrs, during adult hood, those who have focal onset, in those with seizures despite medication use
- CT used if MRI not available or contraindicated
12 lead ECG: to rule out cardiogenic cause of faint?
Important to determine seizure type as this dictates treatment
Pathogenesis of seizures
- Sudden uncontrolled synchronous and repetitive activation of network of neurones
- Structural lesions can cause abnormal neuronal connection and physiology that leads to seizure activity
What is a partial seizure?
These are generated if abnormal activity remains restricted to area of onset
What is a generalised seizure?
his is where abnormal activity becomes generalised to involve large areas of cortex
Seizure classification
Focal onset seizures: these are seizures which start in one part of brain and may affect part of one hemisphere or just a small area in one of the lobes
- These can be focal aware seizures – previously known as simple partial seizures, this means that consciousness is not affected
- Focal impaired awareness seizures – previously known as complex partial seizures or focal seizures which involve a loss of consciousness or impaired consciousness
Generalised onset seizures: seizures which affect both sides of brain at once
- Tonic clonic seizures: jerking and shaking as muscles relax and contract
- Atonic: patient becomes floppy and often falls forwards
- Tonic: patient becomes stiff and often falls backwards
- Myoclonic: muscle jerks
- Absence seizures: previously called petit mal, patient becomes blank and unresponsive, atypical absences start and finish more slowly and last longer than typical absences
Differentials in patients presenting with suspected epileptic seizure
- Vasovagal syncope
- Cardiac arrhythmias
- Panic attacks. Hyperventilation
- Psychogenic non-epileptic seizures, dissociative seizures, pseudoseizures
- TIA
- Migraine
- Medication, alcohol, drugs
- Sleep disorders
- Movement disorders
- Hypoglycaemia
- Transient global amnesia
- Delirium/ dementia
Differentials of seizure specific to children
Febrile convulsions
Breath-holding attacks
- When baby or child stops breathing for <1min and may faint
- Can happen when child frightened or upset, angry etc
- Child may cry then be silent when holding breath, turn blue or grey, be floppy or stiff, faint for 1-2mins, may be confused afterwards
- Usually harmless, children grow out of it by age 4-5
Night terrors
Management of suspected epilepsy
- Urgently refer to specialist if you suspect patient has had first epileptic seizure
- Advise family members re managing a seizure
- Advise patient to stop driving
- Advise re lifestyle factors to reduce risk of seizure e.g. alcohol
- To take a witness of first seizure to specialist appmt
- Contact GP if further attacks occur while waiting to see specialist
Why do we only treat after a patient has had 2 distinct seizures?
(2 seizures within 24hrs is counted as 1)
- This is because a single unprovoked seizure leads to a 40% risk of another seizure within 2 years, therefore more than 1/2 of the people who had one seizure will not have another seizure and will be on medication for no reason **
- This is unless a patient is found to have a structural abnormality or they have a factor found that is likely to cause them to have another seizure
Management of seizure
People having tonic clonic seizure: lasting <5 mins
- Protect from injury
- Cushion head
- Remove glasses
- Remove harmful objects from nearby
- When seizure stops, check airway and place in recovery position and observe until recovered
- Arrange emergency admission if this is first seizure or if second seizure occurs after shortly after first
People having tonic – clonic seizure lasting >5 minutes or >3 seizures in an hour
- In addition to above, buccal midazolam is 1st line in community
- If not available rectal diazepam
- When IV access obtained IV Lorazepam
- Call for ambulance if seizures do not respond promptly or if seizures were prolonged or recurrent or if patient is known to be at risk of repeated seizures or status epilepticus
- Always cool for ambulance if patients first seizure
- Arrange for specialist review
Prescribing and contraceptive advice for women of childbearing age with epilepsy
Give advice to girls with epilepsy before sexually active, advised that enzyme inducing drugs may reduce the effectiveness of oral contraceptives
- Methods unaffected by enzyme inducing drugs include injections or and IUD or IUS
Oestrogen containing contraceptives may reduce effectiveness of lamotrigine
Managing a woman who is pregnant or planning a pregnancy who has epilepsy
- Ensure patient receives pregnancy counselling at time of epilepsy diagnosis, discuss risks of antiepileptic medication on foetus, specifically discuss risk of sodium valproate to foetus
- In woman who is planning a pregnancy advise that most women with epilepsy have a normal pregnancy and delivery, antiepileptic drugs do not increase risk of miscarriage and stillbirth, inadequate seizure control may put foetus of more risk of harm than use of drugs, advise woman regarding risk of uncontrolled seizures, valproate is contraindicated in pregnancy and should only be used in girls and women of childbearing potential as a last resort medication
- Prescribe high-dose folic acid 5 mg daily and continue throughout first trimester
Treatment of focal seizures
Carbamazepine or lamotrigine are first line
Treatment of generalised tonic chronic seizures
- For boys, men and women who are not child bearing age potential offer sodium valproate or lamotrigine
- Lamotrigine may exacerbate myoclonic seizures
- Carbamazepine and oxcarbazepine for those unsuitable for sodium valproate
Treatment of absence seizures
Ethosuximide for those unsuitable for sodium valproate – sodium valproate or ethosuximide for others
Treatment of myoclonic seizures
Sodium valproate or levetiracetam or topiramate
Side effects of levetiracetam/ Keppra
- Can cause patients to become grumpy so ask if patient has any mood disturbances
- Well tolerated drug
What is lamotrigene?
- Sodium channel blocker
- Can cause Stevens-Johnson syndrome
- SJS usually develops up to 2 months after starting anti-convulsant
- Usually a prodromal illness which resembles a viral upper resp tract infection followed by a rapid onset painful red skin rash starting on trunk and spreading
- Rash rarely affects palms and soles
- Immediate management = stop the drug causing it and admit to hospital
- Fluid replacement needed due to fluid loss from blisters
What is phenytoin?
- Inducer of p450 system
- Non-specific sodium channel blocker
Acute side effects
- Dizziness, diplopia, slurred speech
- Confusion, seizures
Chronic side effects
- Gingival hyperplasia
- Hirsutism
- Coarsening of facial features
- Megaloblastic anaemia
- Peripheral neuropathy
- Lymphadenopathy
- Dyskinesia
Patient has the following symptoms, where is the epileptic activity?
Hallucinations
Emotional
Automatisms (lip smacking)
Deja-vu/ dysphasia post-ictal
Feeling of sinking in stomach when going down in a lift - linked to an emotional response
Temporal lobe
Patient has the following symptoms, where is the epileptic activity?
Head/ leg movements
Posturing
Post-ictal weakness
Jacksonian march - starts in one leg, then spreads to involve arm and face
Frontal lobe
Paraesthesia associated with a seizure in which lobe?
Parietal
Management of epilepsy NICE
NICE states that following a first epileptic seizure patient should be referred to specialist and drug treatment should only be started following this review unless:
- Seizure activity observed on EEG, presence of neurological deficit, presence of structural brain abnormality, patient, parent or carer considers risk of further seizure to be unacceptable
Generalised tonic chronic seizures: sodium valproate, lamotrigine, carbamazepine
Absence seizures: sodium valproate or ethosuximide
- Carbamazepine may exacerbate absence seizures
Myoclonic seizures: sodium valproate, clonazepam, lamotrigine
- Carbamazepine may exacerbate myoclonic seizures
Focal seizures: carbamazepine or lamotrigine
Epilepsy/ seizures and driving
1st unprovoked or isolated seizure: 6 months off if there are no anatomical changes and no epileptiform changes on EEG
- If there are, then this increases to 12 months
Patients with established epilepsy
- Seizure free for 12 months: may qualify for license
- No seizure for 5 years: up to 70yrs license likely to be given
- Withdrawal of medication: no driving until 6 months after withdrawal
Post-stroke epilepsy
Seizures after stroke affect 5% of patients
- More likely to occur following a haemorrhagic stroke as opposed to an ischaemic one
- More likely to occur if the stroke was a major stroke and occurred in the cerebral cortex
- Managed in the same way as epilepsy
Good diet for childhood epilepsy?
Ketogenic
