Seizures Flashcards
What is a seizure?
A transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain
What is epilepsy?
Disorder of the brain characterized by an enduring predisposition to generate epileptic seizures.
The clinical definition of epilepsy is?
Diagnosis expanded to include patients with only 1 unprovoked seizure but at significant risk of seizure recurrence
What is the etiology of seizures? (5)
Variable causes, largely unknown
1. Genetics
2. Structural lesions in the brain acquired or genetic
3. Metabolic disorders
4. Infections
5. Immune
Anything that disturbs the normal functioning of the cerebral cortex can cause seizures, and if this abnormality is enduring, it can result in epilepsy.
Synchronous hyperexcitability underyling seizures may be due to: (5)
- Increased excitatory synaptic neurotransmission
- ↓ inhibitory synaptic neurotransmission
- Alteration of voltage-gated ion channels
- Alteration of intra- or extracellular ion concentrations
- Hypersynchrony
- Recruitment of neighbouring neurons into an abnormal firing mode
What is the impact of seizures on patient’s lives? (7)
- Stigma person living with epilepsy (not epileptic person)
- Fear of seizures nature & unpredictability of szs
- Injuries
- Hospitalizations
- Lost productivity
- Anxiety & MDD
- Increase mortality 2-3x higher than general population
Seizures are differentiated into 3 primary types of onset. What are they?
- Focal
- Generalized
- Unknown
What is a focal seizure?
Originate within networks limited to one hemisphere
What is a generalized seizure?
Originate at some point within, and rapidly engaging, bilaterally
distributed networks
What are “unknown” seizures?
Reflects the difficulty to classify unwitnessed seizures and those that occur while the patient is asleep
What is status epilepticus?
Any seizure that does not stop within 5 minutes should be treated as impending status epilepticus (SE)
- Operationally seizures lasting >5 mins or repetitive seizures for > 5 min are treated as SE to prevent consequences and increase response to tx
Patients are often given __ ______ benzodiazepines to use ___ at the onset of seizures to decrease risk of progression to SE
on demand
prn
What “on demand” benzo might be given to an adult, pediatric, and infant <3 months to treat an acute seizure?
Adults commonly - lorazepam sublingual
Pediatrics - midazolam intranasal or buccal
Infants - rectal diazepam
What are some steps to take in seizure first aid in a person experiencing a convulsive seizure? (9)
- Don’t panic - you can help
- Time it. Longer than 5 mins = call an ambulance
- Explain what is going on. Ask to be given space
- Cushion head and neck with something soft
- Roll the person to their side to prevent choking
- Clear the area of dangers
- Do NOT put anything in the mouth
- Do NOT restrain
- Speak gently. Be kind during and after the seizure
Epilepsy is diagnosed based on what?
A combo of clinical history and physical/neuro exam
What are some classes of meds that can lower seizure threshold? (7)
- Analgesics
- Anticancer drugs
- Antimicrobials
- Immunosuppressants
- Psychiatric meds
- Stimulants
- Sympathomimetics and decongestants
What does it mean to lower seizure threshold?
Easier for a seizure to happen
What does an EEG help with in seizure diagnosis? (3)
- Both interictal (before/after sz) and ictal (during sz) recordings are informative
- Screening for epileptiform discharges - Used to determine if focal vs. generalized onset, and estimating risk of recurrence
- Only a snapshot in time so some patients may require multiple EEGs or admission to an inpatient unit that does continuous EEG monitoring
What does brain imaging help with in seizure diagnosis? (2)
- Used to identify structural abnormalities (e.g., focal lesions, brain tumour)
- NOT to observe seizure activity
What labs studies might be done in epilepsy diagnosis? (4)
- Blood glucose
- CBC with diff
- Electrolyte panels (esp. sodium)
- Lumbar puncture (if suspicion of meningitis or encephalitis)
What are the goals of therapy for a seizure patient? (5)
- Complete seizure control (within minutes if status epilepticus then ongoing)
- ↓ seizure frequency, severity, type (ongoing)
- In the 30%–40% of patients that do not achieve complete seizure control - Reduce morbidity and mortality (ongoing)
- Improve quality of life (ongoing)
- Minimize ADEs
Epilepsy is generally well controlled with ___________ or _______
medications; surgery
Some patients may require treatment with antiseizure meds in the short term, but these are generally not continued once the patient’s medical problem has been resolved. Give 3 examples of types of patients
Patients with acute seizures from:
1. Metabolic (e.g., uremia, hypoglycemia, hyperglycemia, hepatic failure)
2. Toxic (e.g., drug overdose or withdrawal)
3. Infectious (e.g., meningitis) etiologies
Long-term treatment of seizures is usually considered when?
Once diagnosis of epilepsy is made
What are the principles for initiating ASM therapy? (2)
- Start with monotherapy
- Titrate slowly
- Start ASM at 1/4 to 1/3 of the initial dose and increase q1-2weeks
- Unless status epilepticus or high risk for harm from seizures –> loading doses
- Minimizes risk of dose-dependent adverse effects
- Patient-specific factors may affect the speed of titration (e.g., titrate over months in the elderly vs. over days if frequent seizures)
What is the epilepsy treatment approach when there is inadequate response to initial therapy? (3)
- Inquire about medication adherence
- Reported that 60% are nonadherent - If at a moderate dose with few adverse effects, titrate up to max dose
- If continuing to experience breakthrough seizures at maximum tolerable dose, consider:
- Initiate a different 1st line ASM as monotherapy start new agent, taper off old (unless intolerable ADEs)
- Initiate combination therapy by adding a 2nd ASM
What are the pros of ASM monotherapy? (3)
- Fewer idiosyncratic reactions
- Increases probability of adherence
- More cost-effective
- ~65% of patients can be maintained on monotherapy
Polytherapy is usually reserved for patients who…
have failed monotherapy with 2-3 drugs
- Typically select an ASM with a different or complimentary MOA
Not all pts require lifelong ASM therapy.
What is the benefit to stopping?
What are the 2 risks?
Benefit:
- Discontinuing 1+ medication will reduce polypharmacy and may decrease adverse effects and improve cognition
Risk:
- Risk of recurrent seizures (impacts driving, personal safety, and psychological well-being)
- Seizure control may be lost long-term
What are 4 factors favoring successful discontinuation of ASM(s)?
- Seizure-free
- 2 years for children
- 2 to 5 years for adults - Normal neurologic exam
- Normalized EEG with treatment
- History of single type of focal seizure or generalized tonic-clonic seizures
What is the best approach to stopping ASM treatment? (3)
- If non-emergency situation, slow and gradual taper is best to prevent relapses and status epilepticus
- If on >1 ASM, each one should be withdrawn separately
- No optimal rate of withdrawal of ASM(s) has been identified, but a schedule of at least 6 weeks seems to be safe
- Versus 9-month period in clinical trial; no different
What are the 3 main non-pharmacologic therapies for epilepsy/seizures?
- Diet
- Surgery
- Vagus Nerve Stimulation (VNS)
What sort of dietary changes can help with seizures? (4)
- Diet: Ketogenic diet
- High fat, low carb, adequate protein diet mimics state of starvation
- Requires strict compliance
- Poorly tolerated by patients - May reduce seizure frequency
- Anti-epileptic mechanisms not fully established - Consider if have not responded to appropriate ASM therapy
When is surgery an option for seizures?
An option for some patients with refractory focal onset epilepsy resistant to multiple ASMs
- The majority of pts achieve seizure-freedom
What is vagal nerve stimulation?
When might it be used? (4)
- Involves a surgical procedure to implant an electrical pulse generator in the chest and attach electrodes to the vagus nerve in the neck
- Pulse generator stimulates the vagus nerve on a regularly scheduled basis
- May reduce seizure frequency
- Mechanism is unknown - Option in refractory focal onset or generalized seizures
What are some general measures of non-pharmacologic therapy to help prevent seizures? (4)
- Adequate sleep/nutrition
- ↓ stress/anxiety
- ↓ alcohol
- Avoid abrupt withdrawal if heavy use - Avoid triggers
- Photosensitivity
- Loud sounds
- Caffeine
- Flashing lights
- Heat/overexertion
What are some considerations to be aware of when thinking of choosing ASM? (9)
- MOA – in relation to sz type
- Evidence of benefit/consensus recommendations
- Comorbidities
- Adverse drug effects
- Teratogenicity
- Drug interactions
- Therapeutic drug monitoring
- Formulations
- $$$/coverage
What are the MOAs of different epilepsy pharmacotherapies? (6)
- Modulation of voltage-gated ion channels
- Sodium, potassium, calcium - ↑ inhibitory effect of gamma-aminobutyric acid (GABA)
- Modulation of synaptic release
- Inhibition of synaptic excitation
- Glutamate receptor activity
- AMPA receptor activity
Most common ADEs of ASMs are ____-_________ and __________
dose-dependent; reversible
What are the CNS side effects of ASMs? (5)
- Sedation**
- Dizziness**
- Blurred or double vision
- Ataxia
- Difficulty concentrating
What are the GI side effects of ASMs? (2)
- Nausea
- Vomiting
What are 2 hypersensitivity reactions that can occur with ASMs?
- SJS
- TEN
Hypersensitivity reactions to ASMs are most likely to occur with which meds? (4)
- Phenytoin
- Carbamazepine
- Lamotrigine
- ?Lacosamide
Cross-sensitivity between ASM agents is possible why?
Due to aromatic hydrocarbon ring
What anti-epileptic drugs should be avoided if a patient develops a phenytoin-related rash? (7)
- CBZ
- Oxcarbazepine
- Eslicarbazepine
- Phenobarbital
- Primidone
- Phenytoin
- Lamotrigine
What anti-epileptic drugs are safe to switch to if a patient develops a phenytoin-related rash? (7)
- Clobazam
- Gabapentin
- Pregabalin
- Lacosamide
- Levetiracetam
- Topiramate
- VPA
ASM exposure during pregnancy has been associated with major congenital malformations and neurodevelopmental delay in the offspring. What are some general measures to take then? (4)
- Discuss pregnancy plans prior to conception
- Consider teratogenic effect of ASM for all women of reproductive age
- Ensure adequate folic acid supplementation
- Aim for seizure-freedom for 9-12 months prior to pregnancy
If possible, avoid which ASM med in women of childbearing age?
VPA
What are 2 preferred ASM drugs to use in women of childbearing age?
- Lamotrigine
- Levetiracetam
Which 3 ASM drugs are strong CYP inducers?
- Phenytoin
- CBZ
- Phenobarbital
Which ASM drug is a CYP inhibitor?
VPA
What DIs is there to be aware of with hormonal contraceptives? (2)
- Many enzyme-inducing ASMs reduce the efficacy of combined hormonal contraceptives
- E.g., phenytoin, carbamazepine, phenobarbital, primidone - Estrogen containing OCP reduces lamotrigine levels
What are the preferred contraceptives to use if patient is on ASM? (3)
- LNG-IUD or copper IUD or progesterone implant
- Depot-medroxyprogesterone
- COC with ≥30mcg EE taken continuously
Therapeutic Drug Monitoring:
When to draw an ASM level? (8)
- Once the desired clinical response has been achieved, to establish the “individual therapeutic rangeâ€
- To assist the clinician in determining the magnitude of a dose increase, particularly with ASMs showing dose-dependent pharmacokinetics (most notably, phenytoin)
- When there are uncertainties in the differential diagnosis of signs or symptoms suggestive of concentration-related ASM toxicity, or when toxicity is difficult to assess clinically (e.g. in young kids)
- When seizures persist despite an apparently adequate dosage.
- When an alteration in pharmacokinetics (and, consequently, dose requirements) is suspected, due to age-related factors, pregnancy, associated disease, or drug-drug interactions.
- To assess potential changes in steady state ASM concentration when a change in drug formulation is made, including switches involving generic formulations.
- Whenever there is an unexpected change in clinical response.
- When poor compliance by the patient is suspected.
How are ASMs classified based on spectrum of activity? (2)
- Narrow
- Generally effective for focal seizures
- Less effective for and may exacerbate idiopathic epilepsy syndromes (myoclonic, absence) - Broad
- Generally effective against all seizure types
Name the ASMs that fall under the narrow spectrum of activity category (8)
- Carbamazepine
- Gabapentin
- Oxcarbazepine
- Phenytoin
- Phenobarbital
- Pregabalin
- Tiagabine
- Vigabatrin
Name the ASMs that fall under the broad spectrum of activity category (9)
- Brivaracetam
- Felbamate
- Lamotrigine
- Levetiracetam
- Perampanel
- Topiramate
- Rufinamide
- Valproate
- Zonisamide
What ASM falls under both narrow and broad spectrum of activity?
Lacosamide
What are the 2 first line ASMs for focal seizures (motor/nonmotor)?
- Carbamazepine
- Lamotrigine
What are the 4 second line ASMs for focal seizures (motor/nonmotor)? (LOVZ)
- Levetiracetam
- VPA
- Oxcarbazepine
- Zonisamide
What are the 3 fourth line (there are no 3rd lines for this condition) ASMs for focal seizures (motor/nonmotor)?
- Gabapentin
- Topiramate
- Phenytoin
What are the third line ASMs for generalized motor (tonic-clonic) seizures? (5) (only have third line available, insufficient evidence for something to be first line)
- CBZ - 1st line in NICE guidelines
- Lamotrigine - 2nd line in NICE guidelines
- Valproate
- Topiramate
- Levetiracetam