IC6- Seizures and Epilepsy I Flashcards
Define seizure
Transient occurence of SSx due to abormal excessive or synchronus neuronal activity in the brain
Define epilepsy
Disease of the brain defined by any of the following conditions:
1. AT LEAST 2 unprovoked seizures occurring > 24 h apart
2. 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
3. Diagnosis of an epilepsy syndrome
Define acute symptomatic seizures
Seizures that result from some immediately recognizable stimulus or cause, i.e. that occur in the presence or close timely association (about a week) with an acute brain insult (metabolic, toxic, structural, infectious, hypoxic, etc.)
Define remote symptomatic seizures
Seizures that occur longer than 1 week following a disorder that is known to increase the risk of developing epilepsy
Define unprovoked seizures
- Seizures occurring in the absence of a potentially responsible clinical condition
OR - Beyond the interval estimated for the occurrence of acute symptomatic seizures
What are the metabolic etiologies of acute symptomatic seizures? (4)
- Hyponatremia
- Hypocalcemia
- Hypomagnesemia
- Hypoglycaemia
What is the etiology of acute symptomatic seizures from toxic substances/ drugs? (4)
- Illicit drugs (e.g. cocaine, amphetamines)
- Drugs (e.g. Tricyclic antidepressants, carbapenems, baclofen)
- ETOH (withdrawal & intoxication)
- Benzodiazepine withdrawal
What are the structural etiologies of acute symptomatic seizures? (2)
- Stroke
- Traumatic Brain Injury
What are the infection/ inflammation etiologies of acute symptomatic seizures? (2)
- CNS infection
- Febrile illness
Define non-epileptic events
Abnormal paroxysmal psychic, sensory and/or motor manifestations which resemble (at least in part) to epileptic seizures but are not related to abnormal epileptiform discharges
What are the 2 types of non-epileptic events?
- Psychogenic non-epileptic seizures (PNES)
- Physiological non-epileptic events
Elaborate more on Psychogenic non-epileptic seizures (PNES)
- Partial alteration of level of consciousness with a partial preservation of awareness
- Caused by stressful psychological experiences or emotional trauma
- Involuntary
Elaborate more on physiological non-epileptic events. Give some examples
- Symptoms of a paroxysmal systemic disorder (e.g. convulsive syncope, hypoglycemia, movement disorders, migraine aura, non-ictal dysautonomia, intoxications, transient ischemic attacks, balance disorder, sleep disorders, panic attacks)
Which factors make a pt more susceptible to ‘drug-induced seizures’
- Previous seizures
- Structural or functional brain abnormalities
- Concurrent drug use
Name some common drugs which are known to lower the seizure threshold (IMPT!) (4)
- High dose β-lactams
- Opioids (analgesics) (eg. tramadol)
- Immunosuppressants (cyclosporine)
- Stimulants (dextroamphetamine, methylphenidate)
- Buproprion (antidepressant/ smoking cessation)
What are the 2 components of the pathophysiology of a seizure?
Hyperexcitability and Hypersynchronization
In the pathophysiology of seizures, what contributes to the hyperexcitability (enhanced predisposition of a neuron to depolarize)? (4)
- Voltage- or ligand-gated K+, Na+, Ca2+, and Cl– ion channels
– Abnormalities in intra- & extracellular substances (e.g., Na+, K+, O2, glucose, etc) - Excessive excitatory neurotransmitters (e.g. glutamine, acetylcholine, histamine, cytokines, etc)
- Insufficient inhibitory neurotransmitters (e.g.GABA, dopamine)
In the pathophysiology of seizures, what contributes to the hypersynchronization?
Hippocampal sclerosis:
- Intrinsic reorganization of local circuits- hippocampus, the neocortex and the thalamus
- Contribute to synchronization and promote generation of epileptiform activity
What is the etiology of epilepsy? (5)
- Structural
- Eg. Hippocampal sclerosis, brain tumours, vascular malformations, glial scarring (including stroke and traumatic brain injury) - Genetic/presumed genetic
- Eg. Dravet syndrome with SCN1A mutations - Neurodegenerative
- Eg. Alzheimer’s disease - Metabolic
- Eg. Inborn errors of metabolism, mitochondrial disorders - Infectious
- Eg. Bacterial menigitis, encephalitis, neurocysticercosis
State the ILAE Classification of epilepsy.
What are the different types of onset of seizures? What do they mean?
- Mode of onset:
1. Focal onset: seizures begin only in ONE hemisphere
2. Generalized onset: seizures begin in BOTH hemispheres
3. Secondarily generalised: being in one hemisphere, then SPREAD to the other - Impairment of consciousness (with/ without dyscognitive features)
Which 3 key features help classisfying epilepsy according to ILAE?
- Where seizures begin in the brain
- Level of awareness during the seizure
- Other features of the seizure
What are the phases of a seizure? (4)
- Prodromal
- Early ictal (aura)
- Ictal
- Postictal
What are the 2 types of focal onset seizures?
- Simple partial seizures: focal onset seizures WITHOUT dyscognitive features
- Complex partial seizures: focal onset seizures WITH dyscognitive features
What is the clinical presentation of focal onset/ simple partial onset of epilapsy (without dyscongnitive feaures) in terms of motor symptoms? (2)
- Clonic movements (eg, twitching or jerking) of the arm, shoulder, face, or leg
- Speech arrest (involves muscles of articulation- dysarthria)
What is the clinical presentation of focal onset/ simple partial onset of epilapsy (without dyscongnitive feaures) in terms of sensory? (3)
- Feelings of numbness or tingling
- Visual disturbances – flashing lights
- Rising epigastric sensation
What is the clinical presentation of focal onset/ simple partial onset of epilapsy (without dyscongnitive feaures) in terms of autonomic symptoms? (3)
- Sweating, salivation, or pallor
- BP
- HR
What is the clinical presentation of focal onset/ simple partial onset of epilapsy (without dyscongnitive feaures) in terms of psychic/ somatosensory symptoms)? (3)
- Flashbacks, deja vu (memory)
- Visual, auditory, auditory, gustatory (taste) or olfactory hallucinations
- Affective symptoms include fear (most common), depression, anger and irritability
Describe the tonic phase of a tonic-clonic “grand mal” seizure
Tonic phase begins first:
- Stiffening of limbs
- Breathing may decrease/ cease altogether
- Cyanosis of nail beds, lips & face → typically returns during clonic phase but may be irregular
Describe the clinical presentation of the clonic phase of a tonic-clonic “grand mal” seizure.
Clonic phase happens after tonic phase:
- Jerking of limbs and face
- Usually lasts 1 min, after that brain is extremely hyperpolarized and insensitive to stimuli
- Incontinence may occur, biting of tongue/ inside of mouth
- Breathing may be noisy and laboured
- Pt may have headache and appear lethargic, confused or sleepy
- Full recovery takes several minutes to hours
Describe the clinical presentation of a clonic seizure (in which age do they occur most frequently in?)
- Clonic jerking → asymmetrical and irregular
- Most frequent in neonates, infants or young children
Describe the clinical presentation of a tonic seizure
- Sudden loss of consciousness and rigid posture of entire body, last 10-20s
- Occur at all ages in the setting of diffuse cerebral damage and learning disability, and are invariably associated with other seizure types
- Characteristic and defining seizure in the Lennox-Gastaut syndrome
Describe the clinical presentation of a myoclonic seizure
- Involves rapid, brief contractions of bodily muscles, usually occurring on both sides of the body concurrently
- On occasion, may involve just one arm or one foot
Describe the clinical presentation of an absence “petit mal” seizure.
Does it occur more frequently in children/ adults?
- Basic lapse in awareness that begins and ends abruptly
- Mistaken as permanent staring
- Last few seconds, NO warning, NO after-effects
- ~50-100 attacks/ day, but often undetected
Demographics:
- More common in children > adults
What may an absence “petit mal” seizure be mistaken for?
How is absence “petit mal” seizure different from this other seizure?
May be mistaken for complex partial seizures
Unlike complex partial seizures, absence seizures…
1. Are never preceded by auras
2. Last seconds (rather than minutes)
3. Begin frequently and end abruptly
4. Produce characteristic EEG pattern “3Hz spike waves”
Describe the clinical presentation of an atonic seizure (including how long it lasts for, what other conditions it is a/w)
- Classic drop attack onto group like a rag doll (astatic seizure) → ALL postural tone suddenly lost
- Short episode, followed by immediate recovery
- Occurs in any age, ALWAYS associated with diffuse cerebral damage and learning disability
- Common in severe symptomatic epilepsies (especially in the Lennox – Gastaut syndrome and in myoclonic astatic epilepsy)
What are the classical characteristics for diagnosis of seizures and epilepsy? (10)
- Aura
- Cyanosis
- Loss of consciousness
- Motor manifestations
- Generalised stiffness of limbs and body
- Jerking of limbs
- Tongue biting
- Urinary incontinence
- Post-ictal confusion
- Muscle soreness
What are the differential diagnosis of seizures/ epilepsy? (4)
- Syncope – “fit ” versus “faint” dilemma
- Transient ischemic attack
- Migraine
- Psychogenic nonepileptic seizures
Which are the investigations that are used in the diagnosis of seizures? (3)
- Scalp electroencephalography (EEG) (including video EEG)
- Magnetic resonance imaging (MRI) with gadolinium
- Biochemical/toxicology
In which type of pts is Magnetic resonance imaging (MRI) with gadolinium ordered for diagnosis of seizure?
For:
- Adult patient who presents with first seizure, patients with focal neurologic deficits, suggestion of focal onset seizure
- Identify focal lesions
What are some limitations of using EEG to diagnose epilepsy?
- Not all Epileptic patients have an abnormal EEG
- EEG can be abnormal in normal persons (false positive)
When is video EEG used?
What are some disadvantages?
- Used for diagnostic problems that cannot be resolved easily in the routine EEG laboratory
- Can be expensive and labor-intensive
Describe the use of biochemical/ toxicology investigations for diagnosis of seizures
- Helps to rule out electrolyte abnormalities
- Serum prolactin- considerable variability, not used routinely
- Creatine kinase (CK) – raised after GTC
What is the risk of seizure recurrence after the 1st seizure?
After 1st seizure, risk of 2nd seizure:
- Within the next 5 years ~30% (80-90% of the 30% had a 2nd seizure within 2 years)
- Higher in presence of
(1) Epileptiform abnormalities on EEG
(2) Prior brain insult (e.g. stroke, brain trauma)
(3) Structural abnormality in brain imaging
(4) Nocturnal seizure
What is the risk of seizure recurrence after 2 unprovoked seizures?
After 2 unprovoked seizures, risk of recurrent seizures at 4 years ~ 70% (high)
What are some key determinants in considering when to start Tx?
- Cause, epilepsy syndrome, EEG findings
- Seizure type
- Tolerability
- Work, need for driver licence, desire to bear children
According to some trials conducted, what were the patient outcomes after giving Tx after the 1st seizure?
- Reduced risk of 2nd seizure
BUT - No effect on long-term prognosis
- No evidence of higher risk of death, injuries, or status epilepticus in patients who did not receive Tx after 1st seizure
In considering when to start Tx, what are some factors we should consider? (4)
- Recurrence risk
- Potential seizure morbidity
- Risk of Tx
- Personal circumstances
What are the 3 goals for Tx of seizures?
- Absence of epileptic seizures
- Absence of ASM-related SEs
- Attainment of optimal QoL
Note: we generally want to aim for seizure freedom!
Is pharmacological Tx or non-pharmacological Tx the mainstay for seizures?
When is the other used?
Pharmacological Tx is the mainstay
Non-pharmacological Tx are usually only used when pharmacological Tx is inadequate
What are the 4 non-pharmacological Tx for seizures?
- Ketogenic diet
- Vagus nerve stimulation (VNS)
- Responsive neurostimulator system (RNS)
- Surgery
What does a ketogenic diet as a non-pharmacological Tx comprise of?
How does it work?
Which age group is it mostly used for?
What is a challenge?
For patients who cannot tolerate or
have not responded well to ASM treatment
Low carbs, high fat
- Induction of ketosis (which has an anti-epileptic effect on the brain)
- Prevention of seizures (mainly in young children)
- Challenging to adhere long term
How does Vagus nerve stimulation (VNS) work? What is it indicated for?
Indicated only for intractable (hard to control) focal seizures
- During a seizure, ‘on demand’ stimulation delivered
When is the Responsive neurostimulator system (RNS) used? (which type of pts)?
New adjunctive therapy to help reduce the frequency of with partial-onset seizures, in patients who have:
– Undergone diagnostic testing that localized ≤ 2 epiloptogenic foci
– Are refractory to ≥ 2 antiepileptic medications
– Have frequent and disabling symptoms
How does the Responsive neurostimulator system (RNS) work?
Continuously monitors electrical activity in the brain, detects patient-specific patterns, and delivers brief pulses of stimulation when it detects activity that could lead to a seizure
When is epilepsy surgery used?
May be useful in selected forms of epilepsy to achieve improvement of symptoms or seizure free status
What are the 4 psychosocial issues surrounding individuals with epilepsy?
- Social stigma
- Employment
- Prohibited from driving in SG
- Caregiver burden
Name some triggers of seizures (9)
For drugs, list out the drugs that can cause seizures
– Hyperventilation
– Photostimulation
– Physical and emotional stress
– Sleep deprivation
– Sensory stimuli
– Infection
– Pyrexia (fever)
– Hormonal changes (time of menses, puberty, or pregnancy)
– Drugs [e.g. theophylline, alcohol, high-dose phenothiazines, antidepressants (especially bupropion), tramadol, carbapenems]
How can patients keep track of their seizures?
With a seizure diary
How to perform appropriate first aid for seizure?
- Ease the person to the floor
- Turn the person gently to one side, helping them breathe
- Clear the area around the person of anything hard or sharp, preventing injury
- Put something soft and flat like a folded jacket, under his or her head
- Remove eyeglasses
- Loosen ties or anything around the neck that may make it hard to breathe
- Time the seizure. Call 911 if > 5 min
What are some things we CANNOT do when providing first aid to a seizure pt?
DO NOT:
- Hold the person down/ try to stop their movement
- Put anything into their mouths
- Give CPR even if they’re breathless
- Offer them food or water until they are fully alert
