ic6 - seizures and epilepsy

Question 1

what is considered non epileptic events and list an example of non epileptic events

Answer 1

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

Question 2

what is PNES

Answer 2

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

Question 3

what are physiological non epileptic events and list examples of such events

Answer 3

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

Question 4

what is “epilepsy”

Answer 4

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

Question 5

what is the pathophysiology of epilepsy

Answer 5

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

Question 6

what are the etiologies of epilepsy and how would they be classified

Answer 6

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

Question 7

what are the types of seizures

Answer 7

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)

Question 8

what is a “seizure”

Answer 8

a transient occurrence of s/sx due to abnormal excessive or synchronous neuronal activity in the brain

Question 9

what are the etiologies of acute symptomatic seizures and how would you classify them

Answer 9

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

Question 10

what are the phases of a seizure

Answer 10

the phases of a seizure are prodromal, early inctal (aura), ictal, postictal

(draw rough shape of graph)

Question 11

what are the factors determining the clinical characteristics of a seizure

Answer 11

determined by (i) site of focus (ii) degree of irritability of the areas of the brain surrounding the focus (iii) intensity of impulse

Question 12

what are some triggers of seizures

Answer 12

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)

Question 13

what are some drugs that lower seizure threshold

Answer 13

theophylline, alcohol, high dose phenothiazines, antidepressants (bupropion, tramadol and carbapenems)

Question 14

how do you classify seizures

Answer 14

seizures are classified based on onset (focal, generalised and secondarily generalised), impairment of consciousness, significance or other features of the seizure

Question 15

what is meant by “impairment of consciousness”

Answer 15

impairment of consciousness defined by loss of awareness of external stimuli or inability to respond to external stimuli in a purposeful and appropriate manner

Question 16

differentiate between the various mode of onset of seizures

Answer 16

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

Question 17

how to classify seizures based on impairment of consciousness

Answer 17

if consciousness is impaired, seizure is “w dyscognitive features”

if consciousness not impaired, seizure is “wo dyscognitive features’

Question 18

how would you term a focal onset seizure with dyscognitive features vs a focal onset seizure without dyscognitive features

Answer 18

focal onset seizures without dyscognitive features are simple partial seizures

focal onset seizures with dyscognitive features are complex partial seizures

Question 19

what is the clinical presentation of a simple partial seizure

Answer 19

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

Question 20

what is “olfactory” and “gustatory”

Answer 20

gustatory has something to do with taste

olfactory has something to do with smell

Question 21

what are the different types of generalised onset seizures and differentiate their characteristics

Answer 21

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

Question 22

what is lennox gastaut syndrome and what is its characteristic type of seizure

Answer 22

lennox gastaut syndrome is childhood epilepsy syndrome and is characterised by tonic and atonic type seizures

Question 23

which types of seizures are assoc w diffuse cerebral damage and learning disability

Answer 23

tonic and atonic generalised seizures

Question 24

what is the clinical presentation of generalised tonic clonic seizures (grand mal)

Answer 24

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

Question 25

what is the clinical presentation of generalised absence seizures (petite mal)

Answer 25

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

Question 26

distinguish petite mal from complex partial seizures

Answer 26

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

Question 27

what is the diagnostic criteria and procedure for epilepsy

Answer 27

hx taking, neurologic exam, concom medical conditions, differential diagnosis, investigations

1. 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)
2. neurologic examination
3. concom medical conditions

Question 28

what are some differential diagnosis concerning epilepsy diagnosis

Answer 28

syncope (fit vs faint dilemma), TIA, migraine, PNES

Question 29

what are the types of investigations that can be done when diagnosing epilepsy (incl possible limitations)

Answer 29

investigations include scalp EEG, video EEG, MRI with gadolinium, biologics/ toxicology

1. 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)
2. 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)
3. 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)
4. biologics: to rule out electrolyte abnormalities (serum prolactin highly variable thus not routinely used, CK elevated after GTC)

Question 30

what are the classical characteristics to be identified for seizure diagnosis (part of hx taking for diagnosis of seizure)

Answer 30

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

Question 31

what is the tx approach for first seizure (consider what the guiding qns are)

Answer 31

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)

Question 32

what are the risk for recurrence of seizures

Answer 32

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%

Question 33

when should tx for epilepsy be initiated (considerations and key determinants)

Answer 33

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)

Question 34

what are the tx goals of epilepsy tx

Answer 34

absence of epileptic seizures, absence of ASM related s/e, attainment of optimal QoL

Question 35

what are the non pharm tx modalities for epilepsy tx (incl indications and limitations)

Answer 35

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)

Question 36

what is “ketosis”

Answer 36

metabolic state whereby your body burns fat for energy instead of glucose

Question 37

what is “neuropace”

Answer 37

a device that works as a responsive neurostimulator system (RNS)

Question 38

what are some issues faced by pts with seizures and epilepsy

Answer 38

they mostly experience psychosocial issues (social stigma, employment, prohibited from driving, caregiver burden) and comorbidities (physical and psychiatric comorbs, intellectual disability)

Question 39

what are the key points for pt education regarding tx for epilepsy

Answer 39

1. identify and avoid preventable seizure triggers relevant to pt
2. ASM s/e and ddi
3. activities like driving, swimming, firearms for NS
4. community resources
5. keep a seizure diary to have info on seizure freq and types, duration of seizures, changes in ASMs, ASM s/e, seizure triggers

Question 40

what is the seizure first aid key points (for GTC) (incl what you should not do)

Answer 40

1. ease person to floor
2. turn person gently onto one side (helps pt breathe)
3. clear the area around the person of anything hard or sharp (helps prevent injury)
4. put something soft and flat like a folded jacket under his or her head
5. remove eyeglasses
6. loosen ties or anything around the neck that may make it hard to breathe
7. 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