Treatment of Epilepsy l Flashcards
Epilepsy related mortality risks (4)
- Sudden Unexplained Death in Epilepsy (SUDEP)
- Status epilepticus
- Unintentional injuries
eg drowning, head injuries & burns - Suicide
Risk factors for SUDEP (3)
- Presence & frequency of tonic-clonic seizures
- Nocturnal seizures
- Lack of seizure freedom
Seizure definition
- a transient occurrence of signs & symptoms due to abnormal excessive or synchronous neuronal activity in brain
Epilepsy definition (3)
- At least 2 unprovoked seizures occurring >24h apart
- 1 unprovoked seizure & probability of further seizures similar to the general recurrence risk after 2 unprovoked seizures, occurring over the next 10 years (60%)
- Diagnosis of epilepsy syndrome
- it is a brain disorder characterised by an enduring predisposition to generate epileptic seizures
Provoked seizures risk factors (5)
- Metabolic
- Toxic
eg illicit drug use, TCA, alcohol, benzodiazepines withdrawal) - Infections
- Inflammations
- Structural
Pathophysiology (2)
- Hyperexcitability
- enhanced predisposition of a neuron to depolarise - Hypersynchronisation
- intrinsic re-organisation of local circuits
Epilepsy risk factors (6)
- Genetic
- Structural
- traumatic brain injury, tumours - Metabolic
- Infections
- Immune
- Unknown
ILAE classification based on 3 key features
- Site seizures begin in
- focal vs generalised - Level of awareness during the seizures
- aware vs impaired - Other factors
- motor or non-motor onset
Simple partial seizures
Focal onset seizures without dyscognitive featues
Complex partial seizures
Focal onset seizures with dyscognitive features
Epileptic syndromes
- epileptic disorder characterised by a cluster of signs & symptoms
Focal onset seizures unique feature
- dejavu (aura)
Generalised onset unique feature (Tonic Clonic)
Tonic - rigidity
Clonic - jerking
Generalised onset unique features (Absence/Petit Mal)
- basic lapse in awareness that begins and ends abruptly
- persistant staring
- mistaken for complex partial seizures
Absence/Petit Mal seizures vs Complex Partial Seizures (4)
- Not preceded by aura
- Last seconds rather than minutes
- Begin frequently & end abruptly
- Produce characteristic EEG patten (3Hz spike waves)
Generalised onset unique features (Atonic)
- classic drop attack (astatic seizures)
- sudden lost in postural tone
- collapse to ground like a rag doll
Diagnosis of epilepsy (6)
- Thorough history taking
- description of seizures
- any aura, preservation of consciousness & post-ictal state - Neurologic examination
- Concomitant medical conditions
- Electroencephalography (EEG)
- MRI with gadolinium
- Biochemistry/toxicology
Differential diagnosis (4)
- Syncope (fainting)
- Transient ischemic attacks
- Migraine
- Psychogenic non-epileptic seizures
Electroencephalography (EEG)
- diagnosis of seizures or epilepsy is considered if there are epileptiform discharges on EEG
- a normal EEG DOES NOT exclude possibility of epilepsy
Electroencephalography (EEG) limitations
- Not all epileptic patients have abnormal EEG
- 50% chance of showing epileptiform activity in a first awake EEG
- 80-90% sensitivity with repeated awake-sleep EEG - EEG can be abnormal in normal persons
Situations when MRI with gadolinium is done (2)
- adult patients who present with 1st seizure
- patients with focal neurological deficits/suggestions of focal onset seizures
Biochemistry/toxicology
- helps to rule out electrolyte abnormalities (eg hyponatremia, hypomagnesemia)
- serum prolactin (not routinely used)
- creatine kinase (raised after GTC)
Risk of seizure occurrence
Risk of second occurrence - 30% within next 5 years, higher in first 2 years - higher in the presence of : ~ epileptiform EEG ~ prior brain insult ~ structural abnomality ~ nocturnal seizures
Risk of recurrent seizures after 2 unprovoked seizures
70% at 4 years
Benefit of initiating treatment after 1st episode of seizures
Reduce the risk of 2nd seizures
Limitations of initiating treatment after 1st episode of seizures (2)
- No effect on long-term prognosis
2. No evidence of higher risk of death, injuries or status epilepticus in patients with deferred treatment
Factors to consider when initiating treatment (4)
- Recurrence risk
- 30% after 1 episode
- 70% after 2 episodes - Potential seizure morbidity
- Risk of treatment
eg ADR - Personal circumstances
eg compliance to medication
Treatment goals for epilepsy (3)
- Absence of epileptic seizures (symptoms)
- Absence of anti-epileptic drug SE
- Attainment of optimal quality of life
2/3 of patients are able to achieve seizure-freedom
Types of treatments for epilepsy
- Pharmacological ASM (mainstay)
- monotherapy preferred - Non-pharmacological
- Keto diet
- Vagus Nerve Stimulation
- Responsive Neurostimulator System (RNS)
- Epilepsy surgery
- Seizure diary
Factors influencing ASM choice (6)
- Seizure type
- Epilepsy syndrome
- Co-medication
- Co-morbidity
- Patient’s preference
- National/Institutional
- costs
- guidelines
Rapid titration required
Cannot use lamotrigine & topiramate (req slow titration)
Epilepsy with migraine
Use topiramate
Epilepsy with depression/anxiety
Caution when using levetiracetam
Women with child bearing potential
Avoid valproate
Consider levetiracetam & lamotrigine
Monotherapy ASM treatment benefits (6)
- Lower incidence of ADR
- Absence of DI
- Reduced risk of birth defects
- Lower cost
- Easier to correlate response & ADR
- Better adherence
Dosing features of ASM initiation (1st line)
- Start low
- If seizure continue but no SE
- increase dose of ASM - If seizures continue despite max tolerated dose or intolerable to SE at low doses
- review diagnosis & drug appropriateness
- check adherence
- change ASM - If patient tolerates 1st and 2nd line agent but with suboptimal responses
- combination ASM therapy
Drug resistant epilepsy
- failure of adequate trials of 2 tolerated ASM
- regardless monotherapy or in combination
Keto diet
- for patients that cannot tolerate or have not responded well to ASM treatment
- comprises of low carb high fat diet to induce ketosis
- used mainly in children to prevent seizures
- challenging to adhere long term
Epilepsy surgery
- not usually advocated early
- advocated early therapy for specific epileptic syndromes
Patient education for epilepsy (4)
- avoid preventable seizure triggers
- counsel on ADR & potential DDI
- activities (unintentional injuries from seizures)
eg swimming - community resources available to support them
Seizures triggers (9)
- Hyperventilation
- Photostimulation
- Physical & emotional stress
- Sleep deprivation
- Electrolyte imbalance
- Sensory stimuli
- Infection
- Hormonal changes
eg pregnancy, menses, puberty - Drugs
eg TCA, anticholinergics, bupropion
First aid for seizures (7)
- Ease the person to the floor
- Turn the person gently to 1 side to help breathing
- Clear the area around the person to prevent injury
- Put something soft/flat under heard
- Remove eyeglasses
- Loosen ties or anything around the neck
- Time the seizures (if >5min call 995)
Things not to do on patients with seizures (4)
- Do not hold the person down
- Do not put anything in the person’s mouth
- Do not try to give mouth-mouth breathing
- even if look pale (hypoxia after tonic) - Do not offer food/water until patient is fully alert
Focal onset
1 hemisphere affected
Generalised onset
Both hemispheres affected
Ion channels (4)
Depolarise :
- Na+
- influx - Ca2+
Hyperpolarise :
- K+
- efflux - Cl-