Epilepsy Flashcards
definition of epilepsy
epilepsy = >2 seizures
seizure: paroxysmal synchronised cortical electrical discharges
Epilepsy is a recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifesting as seizures.
Convulsions are the motor signs of electrical discharges
focal seizure
localised to specific cortcial regions eg temporal lobe, frontal lobe, occipital, complex partial
often seen w/o underlying structural disease
Older nomenclature divided into:
- simple partial (does not affect consciousness)
- awareness not impaired
- focal motor, sensory (olfactory, visual etc)
- autonomoic
- psychic sx
- no post-ictal sx
- complex partial seizures (affects consciousness)
- awareness impaired - either at seizure onset or following a simple partial aura
- most commonly arise from temporal lobe - post-ictal confusion
- secondary generalised (evolving to a bilateral convulsive seizure)
- In ⅔ of patients with partial seizures, the electrical disturbance, which starts focally, spreads widely, causing a generalized seizure, which is typically convulsive.
generalised seizure
originate in and rapidly engalging bilaterally distributed networks = simultaneous onset of widespread electrical discharge with no localising feature to 1 hemisphere
affect consciousness
tonic clonic
absence attacks
myoclonic
atonic - drop attacks
tonic seizures
aetiology of epilepsy
mainly idiopathic
Primary epilepsy syndromes (e.g. idiopathic generalised epilepsy, temporal lobe epilepsy, juvenile myoclonic epilepsy)
secondary seizures (symptomatic epilepsy):
- tumour
- infection - meningitis, encephalitis, abscess
- inflammation - vasculitis, rarely MS
- toxic/metabolic - sodium imbalance, hyper- or hypoglycaemia, hypoxia, porphyria, liver failure
- Drugs (e.g. including withdrawal e.g.alcohol, benzodiazepines).
- vascular (stroke) - haemorrhage, infarction
- vascular malformations
- congenital abnormalities - cortical dysplasia or dysembryoplastic neuroepithelial tumour
- neurodegenerative disease - Alzheimer’s
- malignant htn or eclampsia
- trauma - cortical scarring
- hippocampal sclerosis (eg after febrile convulsion)
- tuberous sclerosis
- sarcoidosis
- SLE
- PAN
- Ab to VGKC
common seizure mimics
syncope
migraine
non-epileptiform seizure disorder (e.g. dissociative disorder)
pathology of seizures
imbalance in inhib and excitatory currents eg Na or K ion channels, or neurotransmission ie glutamate or GABA neuro-transmitters in the brain
pricipitants of seizures
any trigger that promotes excitation of cerebral cortex:
- flashing lights
- drugs
- sleep deprivation
- metabolic
- but often cryptogenic
epidemiology of epilepsy
common
prevalence 1%
peak age of onset is early childhood or elderly
key qns in epilepsy Hx
rapidity of onset
duration
alteration in consciousness
tongue biting or incontinence
rhythmic synchronous limb jerking
post-ictal period
drug history - alcohol, recreational drugs
if this is the 1st seizure ask about funny turns/odd behaviour previously - Deja vu and odd episodic feelings of fear
any triggers - alcohol, stress, flickering lights/TV - triggered attacks recur
focal seizures
frontal lobe focal motor seizures
temporal lobe
frontal lobe complex partial seizure
Sx of frontal lobe focal motor seizures
motor convulsions - posturing or peddling movement of the legs
Jacksonian march (spasm spreading from mouth or digit, retained awareness).
motor awareness
subtle bahvioural disturbances - often diagnosed as psychogenic
dysphasia or speech arrest
post-ictal flaccid weakness (Todd’s paralysis),
temporal lobe focal seizure sx
aura - visceral and psychic symptoms: fear or deja-vu sensation, feeling in gut, strange smells or flashing lights
hallucinations - olfactory, gustatory, sound
Automatisms—complex motor phenomena with impaired awareness, varying from primitive oral (lip smacking, chewing, swallowing) or manual movements (fumbling, fi ddling, grabbing) , to complex actions
dysphasia
jamais vu - everything seems strangely unfamiliar
Emotional disturbance, eg sudden terror, panic, anger, or elation, and derealization (out-of-body experiences).
delusional behaviour
bizarre associations
post-ictally - dysphasia
frontal lobe complex partial seizure sx
loss of consciousness with automatisms and rapid recovery
types of generalised seizure
tonic clonic (grand mal)
absence (petit mal)
non-convulsive status epilepticus
myoclonic
atonic (akinetic)
infantile spasms
sx of tonic clonic seizure
vague symptoms before attack - irritability
loss of consciousness
tonic phase - generalised muscle spasm, limbs stiffen
clonic phase - repetitive synchronised jerks
may have 1 w/o other
faecal/urinary incontinence
tongue biting
after - usually impaired consciousness, lethargy, confusion, headache, backpain, stiffness
absence seizure sx
usual onset in childhood
loss of consciousness but maintained posture - stop talking and stare into space for a few seconds
blinking or rolling of eyes
repetitive motor actions - chewing
no post-ictal phase
sx of myoclonic seizures
sudden jerk or a limb, face or trunk
pt may be thrown suddenly to the ground, or have a violently disobedient limb
non-convulsive status epilepticus sx
acute confusional state
often fluctuating
difficult to distinguish from dementia
signs of epilepsy
depends on aetiology
normal between seizure
focal abnormalities indicative of brain lesions
Ix for epilepsy
blood
- FBC
- UE
- LFT
- glucose
- Ca, Mg
- ABG
- toxicology screen
- prolactin - transient increase shortly after a true seizure
EEG
- confirm or refute diagnosis
- helps classify epileptic syndrome
- Usually performed inter-ictally and often normal and does not rule out epilepsy.
- can be false +ve
- ictal EEGs combined with video telemetry are more useful but requires adequate facilities.
- only do emergency EEG if non-convulsive status is the problem
CT/MRI
- for structural, space-occupying and vascular lesions
LP - if infection suspected
HIV serology
drug levels - are they compliant to anti-epileptic
what is status epilepticus
seizure>30min, failure to regain consciousness
Mx for status epilepticus
treatment started in 5-10min - higher success
resus and protect airway, breathing and circ
check glucose - give if hypo, consider thiamine
IV lorazepam or IV/PR diazepam - repeat once after 15min if needed
if recur/fail to respond - IV phenytoin (15mg/kg) under ECG monitoring
Alternative IV agents include phenobarbitone, levetiracetam or sodium valproate.
if fail - GA - requires intubation and mechanical ventilation
treat cause eg hypoglycaemia, or hyponatraemia
check plasma levels of all anticonvulsants
medical Mx of epilepsy
only start anti-epileptic drugs after >2 unprovoked seizures
lamotrigine or carbamazepine - first line for focal. 2nd line: levetiracetam, oxcarbazepine, or sodium valproate
sodium valproate or lamotrigine - generalised. 2nd line: carbamazepine, clobazam, levetiracetam, or topiramate.
- Absence seizures: 1st line: sodium valproate or ethosuximide. 2nd line: lamotrigine.
- Myoclonic seizures: 1st line: sodium valproate. 2nd line: levetiracetam, or topiramate (but more SE). Avoid carbamazepine and oxcarbazepine—may worsen seizures.
Tonic or atonic seizures: Sodium valproate or lamotrigine.
Other commonly used agents include phenytoin, levetiracetam, clobazam, topiramate, gabapentin, vigabatrin, ethosuximide (absence)
start treatment with single anti-epileptic drug (AED) - slowly build up doses over 2-3mo until controlled/max dose
. To switch drugs, introduce the new drug slowly, and only withdraw the 1st drug once established on the 2nd
pt education for epilepsy
avoid triggers eg alcohol
encourage seizure diaries
Recommend supervision for swimming or climbing, driving is only permitted if seizure free for 6 months.
counselling on employment, sport, insurance
women of childbearing age should be counseled regarding possible teratogenic effects of AEDs and should consider taking supplemental folate to limit the risk.
Drug interactions e.g. enzyme-inducing AEDs can limit the effectiveness of oral contraception.
surgery for refractory epilepsy
removal of definable epileptogenic focus - determined from EEG, intracortical recordings, ictal SPECT, neuropsychometry. Risk of causing focal neurological deficits
vagus nerve stimulator
deep brain stimulation
complications of epilepsy
Fractures with tonic-clonic seizures, behavioural problems, suddendeath in epilepsy (SUDEP).
Complications of AEDs (e.g. gingivial hypertrophy with phenytoin, neutropenia or osteoperosis with carbamazepine, Stevens-Johnson syndrome with lamotrigine).
prognosis for epilepsy
50% mortality at 1yr
mortality 2/100000/yr, directly related to seizure or secondary to injury
seizure prodrome
lasts hours or days before seizure
may be change in mood or behaviour
general post-ictal sx/signs
headache
confusion myalgia
why do you have to rule out provoking causes for seizures
most people will have a seizure with enough provocation
not many provoked seizures recur
provocations:
- trauma
- stroke
- haemorrhage
- raised ICP
- alcohol or benzodiazepine withdrawal
- metabolic disturbance (hypoxia, low/high Na, low ca, low/high glucose, uraemia, liver disease)
- infection (meningitis, encephalitis)
- high temp
- drugs - tricyclics, cocaine
unprovoked seizures have a higher recurrence rate
atonic seizure sx
sudden loss of muscle tone = fall
no LOC
infantile spasms
commonly associated with tuberous sclerosis
parietal lobe focal seizure sx
sensory disturbances - tingling, numbness, pain (rare)
motor sx (due to spread to the pre-central gyrus)
occiptal love focal seizure sx
visual phenomona eg spots, lines, flashes
stopping AEDs
under specialist supervision if been seizure free for >2yrs and after assessing risks and benefits
dose must be decreased slowly over 2-3mo or >6mp for benzodiazepines and barbituates
psychological therapy for epilepsy
relaxation
CBT
might benefit some people - dont reduce seizure frequency so use as adjunct
sudden unexpected death in epilepsy
more common in uncontrolled epilepsy
may be related to nocturnal seizure-associated apnoea or asystole
Those with epilepsy have 3x increased mortality.
>700 epilepsy-related deaths are recorded/ yr in the UK; up to 17% are SUDEPs.
carbamazepine
(As slow-release.)
Initially 100mg/12h, increase by 200mg/d every 2wks up to max 1000mg/12h.
SE: leucopenia, diplopia, blurred vision, impaired balance, drowsi ness, mild generalized erythematous rash, SIADH
lamotrigine
As monotherapy,
initially 25mg/d, increase by 50mg/d every 2wks up to 100mg/12h (max 250mg/12h).
Halve monotherapy dose if on valproate; double if on carbamazepine or pheny toin (max 350mg/12h).
SE: maculopapular rash—occurs in 10% (but 1/1000 develop Stevens-Johnson syndrome or toxic epidermal necrolysis) typically in 1st 8wks, especially if on valproate; warn patients to see a doctor at once if rash or flu symptoms develop;
Other SES: diplopia, blurred vision, photosensitivity, tremor, agitation, vomiting, aplastic anaemia.
levetiracetam
Initially 250mg/24h, increase by 250mg/12h every 2wks up to max 1.5g/12h (if eGFR >80).
SE: psychiatric side effects are common, eg depression, agitation.
Other SES: D&V, dyspepsia, drowsiness, diplopia, blood dyscrasias.
sodium valproate
Initially 300mg/12h, increase by 100mg/12h every 3d up to max 30mg/kg (or 2 . 5g) daily.
SE: teratogenic. Nausea is very common (take with food).
Other SES: liver failure (watch LFT especially during 1st 6 months), pancreatitis, hair loss (grows back curly), oedema, ataxia, tremor, thrombocytopenia, encephalopathy (hyperammonaemia).
phenytoin
No longer 1st line due to toxicity (nystagmus, diplopia, tremor, dysarthria, ataxia)
SE: reduced intellect, depression, coarse facial features, acne, gum hyper trophy, polyneuropathy, blood dyscr asias.
Blood levels required for dosage.
which AEDs are liver enzyme inducing
Carbamazepine, phenytoin, and barbiturates
