ic6 - seizures and epilepsy Flashcards
what is considered non epileptic events and list an example of non epileptic events
non epileptic events are events that have abnormal paroxysmal psychic, sensory and/or motor manifestations which resemble epileptic seizures but are not related to abnormal epileptiform discharges
psychogenic non epileptic seizures (PNES) and physiological non epileptic events are non epileptic events
what is PNES
psychogenic non epileptic seizures (PNES) are events assoc with partial alteration of level of consciousness with partial preservation of awareness and is caused by stressful physiological experiences or emotional trauma, and is involuntary
what are physiological non epileptic events and list examples of such events
they are sx of a paroxysmal systemic disorder
eg. sleep disturbances, panic attack, migraine aura, hypoglycemia, convulsive syncope, movement disorders, non-ictal dysautonomia, intoxications, TIA, balance disorders
what is “epilepsy”
epilepsy is a disease of the brain defined by any of the following conditions:
(i) at least 2 unprovoked seizures occurring >24h apart
(ii) one unprovoked seizure with a recurrence probability similar to the general recurrence risk after two unprovoked seizures occurring over the next 10 years (at least 60%)
(iii) diagnosis of epilepsy syndrome
what is the pathophysiology of epilepsy
hyperexcitability and hypersynchronisation
[hyperexcitability] refers to the enhanced predisposition of a neuron to depolarise, factors incl (i) voltage/ligand gated ion channels (Na, K, Ca, Cl) (ii) abnormalities in intra and extracellular substances (iii) excessive excitatory neurotransmitters (ACh, histamine, glutamine, cytokines) (iv) insufficient inhibitory neurotransmitters (GABA, dopamine)
[hypersynchronisation] involves hippocampal sclerosis which is the intrinsic reorganisation of local circuits involving the hippocampus, thalamus and neocortex which contributes to synchronisation and promotes generation of epiletiform activity
what are the etiologies of epilepsy and how would they be classified
they can be classified under structural, genetic or presumed genetic, neurodegenerative, metabolic and infectious
[structural] hippocampal sclerosis, brain tumor, glial scarring (incl stroke, traumatic brain injury), vascular malformations
[genetic] dravet syndrome with SCN1A mutations
[neurodegenerative] alzhiemer’s
[metabolic] inborn errors of metabolism, mitochondrial defects
[infection] bacterial meningitis, encephalitis, neurocysticercosis
what are the types of seizures
there are acute, remote symptomatic seizures and unprovoked seizures
[acute] seizures that result from an immediately recognisable stimulus (in presence or close timely assoc of approx 1w)
[remote] seizures that occur longer than 1 week following a disorder that is known to incr risk of developing epilepsy
[unprovoked] seizures occurring in absence of a potentially responsible clinical condition or beyond the interval estimated for the occurrence of an acute symptomatic seizure (1w)
what is a “seizure”
a transient occurrence of s/sx due to abnormal excessive or synchronous neuronal activity in the brain
what are the etiologies of acute symptomatic seizures and how would you classify them
they can be classified under structural, metabolic, infection or inflamm, toxic substances or drugs
[structural] stroke, traumatic brain injury
[metabolic] hypoNa, hypoCa, hypoMg, hypoglycemia
[infection or inflamm] CNS infection, febrile illness
[toxic substances or drugs] illicit drugs, drugs, alcohol (withdrawal and intoxication), withdrawal of benzodiazepine
what are the phases of a seizure
the phases of a seizure are prodromal, early inctal (aura), ictal, postictal
(draw rough shape of graph)
what are the factors determining the clinical characteristics of a seizure
determined by (i) site of focus (ii) degree of irritability of the areas of the brain surrounding the focus (iii) intensity of impulse
what are some triggers of seizures
hyperventilation, photostimulation, physical and emotional stress, sleep deprivation, sensory stimuli, infection, hormonal changes (time of menses, puberty or pregnancy), drugs that lower seizure threshold (theophylline, alcohol, high dose phenothiazines, antidepressants like buproprion and tramadol and carbapenems)
what are some drugs that lower seizure threshold
theophylline, alcohol, high dose phenothiazines, antidepressants (bupropion, tramadol and carbapenems)
how do you classify seizures
seizures are classified based on onset (focal, generalised and secondarily generalised), impairment of consciousness, significance or other features of the seizure
what is meant by “impairment of consciousness”
impairment of consciousness defined by loss of awareness of external stimuli or inability to respond to external stimuli in a purposeful and appropriate manner
differentiate between the various mode of onset of seizures
seizures are classified into focal onset, generalised onset and secondarily generalised onset
focal onset seizures are seizures that begin only in one hemisphere
generalised onset seizures are seizures that begin in both hemisphere
secondarily generalised onset seizures are seizures that start in one hemisphere then spread to the other
how to classify seizures based on impairment of consciousness
if consciousness is impaired, seizure is “w dyscognitive features”
if consciousness not impaired, seizure is “wo dyscognitive features’
how would you term a focal onset seizure with dyscognitive features vs a focal onset seizure without dyscognitive features
focal onset seizures without dyscognitive features are simple partial seizures
focal onset seizures with dyscognitive features are complex partial seizures
what is the clinical presentation of a simple partial seizure
simple partial seizure is focal onset without dyscognitive features
types of sx presented involve motor, sensory, autonomic, psychic
[motor] (i) clonic (twitching and jerking) movements of arms, shoulders and legs (ii) speech arrest (dysarthria)
[sensory] (i) numbness or tingling (ii) visual disturbances (iii) rising epigastric sensation
[autonomic] (i) sweating, salivation, pallor (ii) HR, BP
[psychic] (i) flashbacks or dejavu (ii) visual, auditory, olfactory and gustatory hallucinations (iii) fear, depression, anger, irritability
what is “olfactory” and “gustatory”
gustatory has something to do with taste
olfactory has something to do with smell
what are the different types of generalised onset seizures and differentiate their characteristics
tonic, clonic, myoclonic, atonic
[tonic] sudden loss of consciousness and rigid posture of entire body, lasts 10-20sec, occur in all ages and assoc w diffuse cerebral damage and learning disability, characteristic of lennox gastaut syndrome
[clonic] jerking that is often asymmetrical and irregular, occur more freq in neonates, infants and young children
[myoclonic] rapid brief contractions of bodily muscles that usually occurs on both sides of the body concurrently
[atonic] drop attack (astatic seizure) in which all postural tone suddenly lost, short episode f/b immediate recovery, occurs in all ages and assoc w diffuse cerebral damage and learning disability, characteristic of lennox gastaut syndrome
what is lennox gastaut syndrome and what is its characteristic type of seizure
lennox gastaut syndrome is childhood epilepsy syndrome and is characterised by tonic and atonic type seizures
which types of seizures are assoc w diffuse cerebral damage and learning disability
tonic and atonic generalised seizures
what is the clinical presentation of generalised tonic clonic seizures (grand mal)
tonic -> clonic
begins with lost of consciousness and stiffening of limbs f/b jerking of limbs and face
during tonic phase, there may be reduced or no breathing
during tonic phase, cyanosis of nailbeds, lips and face though typically return during clonic phase but may be irregular
clonic phase usually last 1 min (brain is extremely hyperpolarised and is insensitive to stimuli
incontinence may occur along with biting of tongue or inside of mouth, breathing may be noisy and laboured
following seizure, pt may have HA and appear lethargic, confused or sleepy
full recovery takes mins to hrs
what is the clinical presentation of generalised absence seizures (petite mal)
usually manifests as a basic lapse in awareness that starts and ends abruptly
lasts a few seconds only thus often undetected
more common in children than in adults (first onset typically 4-12yo, rarely after 20yo)
may be mistaken for complex partial seizures
distinguish petite mal from complex partial seizures
petite mal has no preceding aura, lasts for a few seconds only (instead of mins), begins and ends abruptly, produce EEG patterns of 3Hz spike waves
what is the diagnostic criteria and procedure for epilepsy
hx taking, neurologic exam, concom medical conditions, differential diagnosis, investigations
- hx taking: description of onset, duration and characteristics of seizure (observers are useful in providing details and pt are useful in describing aura, preservation of consciousness and post ictal state)
- neurologic examination
- concom medical conditions
what are some differential diagnosis concerning epilepsy diagnosis
syncope (fit vs faint dilemma), TIA, migraine, PNES
what are the types of investigations that can be done when diagnosing epilepsy (incl possible limitations)
investigations include scalp EEG, video EEG, MRI with gadolinium, biologics/ toxicology
- scalp EEG: placing of electrodes non invasively, essential tool for diagnosis and classification of seizures and epileptic syndromes -> if diagnosis of seizures or epilepsy considered, epileptiform discharges on EEG can confirm diagnosis (note that a normal EEG does not rule out possibility of epilepsy, limitations include not all pt w epilepsy will have abnormal EEG and healthy pts may have abnormal EEG)
- video EEG: video recording to run concurrent with EEG recording to see correlation between internal and external events (limitations are that it is expensive and labour intensive)
- MRI with gadolinium: indicated for (i) adult pts who present with first seizure (ii) pts with focal neurologic deficits (iii) pts with suggested focal onset seizure, to identify focal lesions (mesial temporal sclerosis, focal cortical dysplasia, remote injury (eg. from prev stroke) tumor, vascular malformations)
- biologics: to rule out electrolyte abnormalities (serum prolactin highly variable thus not routinely used, CK elevated after GTC)
what are the classical characteristics to be identified for seizure diagnosis (part of hx taking for diagnosis of seizure)
aura, cyanosis, generalised stiffness of limbs and body, jerking of limbs, loss of consciousness, tongue biting, urinary incontinence, motor manifestations, muscle soreness, post ictal confusion
what is the tx approach for first seizure (consider what the guiding qns are)
guiding qns: was it a seizure, was it first seizure (if not what is the likely cause), does pt need ASM (consider risk of seizure recurrence, pt factors)
what are the risk for recurrence of seizures
after first seizure, risk of second seizure within next 5 yrs is approx 30%
risk of having second seizure after first seizure higher in presence of (i) epileptiform abnormalties on EEG (ii) prior brain insult eg. stroke, brain trauma (iii) structural abnormality identified in brain imaging (iv) nocturnal seizure
after two unprovoked seizures, risk of recurrent seizures at four yrs approx 70%
when should tx for epilepsy be initiated (considerations and key determinants)
consider: recurrence risk, potential seizure morbidity, risk of tx, personal circumstances
key determinants: cause, epilepsy syndrome, EEG findings, seizure type, tolerability, pt factors (work, need for driver license, desire to bear children)
what are the tx goals of epilepsy tx
absence of epileptic seizures, absence of ASM related s/e, attainment of optimal QoL
what are the non pharm tx modalities for epilepsy tx (incl indications and limitations)
ketogenic diet, vagus nerve stimulation (VNS), responsive neurostimulator system (RNS), surgery
[ketogenic diet] low carb high fat, induction of ketosis, indicated for all pts who cannot tolerate or have not responded well to ASM (limitations are that it is hard to adhere to thus usually initiated in young children mostly)
[VNS] involves placing electrodes attached around left branch of vagus nerve and connected to programmable stimulator which delivers cyclical stimulation, indicated for intractable (aka hard to control) focal seizures
[RNS] stimulator implanted in skull under scalp and leads implanted in the brain, it continuously monitors electrical activity in the brain and detects pt specific patterns and delivers brief pulses of stimulation when it detects activity that could lead to a seizure, indicated as a new adjunctive tx for (i) pts who undergone diagnostic testing that localised 2 or less epileptogenic foci (ii) pts who are refractory to 2 or more ASM (iii) pts with freq and disabling sx
[surgery] may be useful in selected forms of epilepsy to achieve improvement of sx or seizure free status (temporal lobe epilepsy w/wo mesial temporal sclerosis, frontal lobe epilepsy w/wo identifiable lesion on MRI, last option for certain refractory cases)
what is “ketosis”
metabolic state whereby your body burns fat for energy instead of glucose
what is “neuropace”
a device that works as a responsive neurostimulator system (RNS)
what are some issues faced by pts with seizures and epilepsy
they mostly experience psychosocial issues (social stigma, employment, prohibited from driving, caregiver burden) and comorbidities (physical and psychiatric comorbs, intellectual disability)
what are the key points for pt education regarding tx for epilepsy
- identify and avoid preventable seizure triggers relevant to pt
- ASM s/e and ddi
- activities like driving, swimming, firearms for NS
- community resources
- keep a seizure diary to have info on seizure freq and types, duration of seizures, changes in ASMs, ASM s/e, seizure triggers
what is the seizure first aid key points (for GTC) (incl what you should not do)
- ease person to floor
- turn person gently onto one side (helps pt breathe)
- clear the area around the person of anything hard or sharp (helps prevent 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 lasts longer than 5 mins
should NOT
1. hold person down or try to stop his or her movements
2. put anything in person’s mouth as can injure teeth or jaw
3. give mouth to mouth breaths (they typically can start breathing on their own again after a seizure)
4. offer person water or food until he or she is fully alert
