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Flashcards in Epilepsy Deck (27)
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1

possible triggering factors? nondrug

 Sleep deprivation
 Sensory overstimulation
 Hyperventilation (e.g., breathlessness, asthma attacks)  Allergies
 Emotional stress
 Hormonal changes (e.g., during puberty, pregnancy)
 Infections & illnesses
 Head trauma
 Congenital/perinatal complications

2

possible triggering factors? drug

Certain drugs (e.g., anaesthetics, antibiotics, antidepressants, NSAIDs, opioid analgesics) may lower the threshold for induction of seizures

Withdrawal of drugs (e.g., alcohol, benzodiazepines, drugs of abuse)

Excessive intake of AED --> supratherapeutic AED-induced ADRs

Missed AED medication --> subtherapeutic serum AED concentration

? Pertussis vaccine (apparent increased risk of febrile seizures)

3

Basic physiology of a seizure episode can be traced to instability in a single neuronal cell membrane or group of cells around it

Seizure activity is characterised by synchronised paroxysmal discharges occurring in a large population of neurons within the cortex

Basic physiology of a seizure episode can be traced to instability in a single neuronal cell membrane or group of cells around it

Seizure activity is characterised by synchronised paroxysmal discharges occurring in a large population of neurons within the cortex

4

Excess excitability spreads in Local region

 Partial seizure

5

Excess excitability spreads in Widespread region

Generalised seizure

6

Biochemical mediators of epileptic seizures:

 Abnormal K+ conductance
 Defects in voltage-sensitive ion channels
 Deficiencies in membrane ion-linked ATPases (usually  neuronal membrane instability)
 Excessive release of excitatory neurotransmitters (e.g., acetylcholine, histamine, cytokines, etc)
 Insufficient release of inhibitory neurotransmitters (e.g., GABA, dopamine)
 Abnormalities in intra- & extracellular substances (e.g., Na+, K+, O2, glucose, etc) that may affect normal neuronal activity
 Reductions in neuronal threshold to electrical/mechanical stimuli
 Excessive tendency for propagation of seizure discharge from focus

7

Accurate history is best provided is a person who has observed the patient’s repeated events, not necessarily from the patient himself

Accurate history is best provided is a person who has observed the patient’s repeated events, not necessarily from the patient himself

8

Patient is useful in describing details of auras, preservation of consciousness, and post-ictal state

Patient is useful in describing details of auras, preservation of consciousness, and post-ictal state

9

Positive identification of the classical characteristics

 Aura
 Cyanosis
 Unconsciousness

 Motor manifestations
- Generalised stiffness of limbs and body
- Jerking of limbs
- Tongue biting
- Urinary incontinence
- Post-ictal confusion
- Muscle soreness
- Headaches

10

Diagnostic procedures

Electroencephalogram (EEG)
- Critical for identifying seizure type & for elderly patients
- False positive results are possible where:
 Loss of consciousness is due to syncope
 Results do not correlate with other presenting features

Repeated assessment may be useful if first EEG was not conclusive

Magnetic resonance imaging
- Currently the imaging method of choice
- Useful for detecting brain lesions/anatomic defects
- Also recommended for patients refractory to 1st-line antiepileptics

Computed tomography
- Used in urgent cases or if MRI is contraindicated

Video diagnosis
- Increasingly being used for diagnosis in patients with suspected psychogenic non-epileptic seizures (PNES)

Biochemical/toxicology
- Helps to rule out electrolyte abnormalities, renal/hepatic diseases and exogenous toxicity

Serum prolactin
- May help differentiate between PNES in adults and adolescents

Lumbar puncture
- Helps to rule out presence of meningitis or encephalitis in cases where patient exhibits signs of sepsis

11

Misdiagnosis

Diagnosis may be complicated by resemblance of similar symptoms in other clinical conditions:
 Loss of consciousness can be due to
- Transient cardiac arrhythmia
- Transient ischaemic attacks
- Hypoglycaemia
- Panic attacks

 Abnormal kinetic movement
- Movement disorders in sleep and wake
- Tremors / paroxysmal choreoathetosis / dystonia
- Drop attacks or cataplexy

 Provoked seizure
- Refers to seizures with an obvious and immediate cause
- Most commonly associated with:
 Strokes
 Trauma
 Infections
 Effects of alcohol (intoxication and withdrawal)
 Sleep deprivation

12

Determining the type of seizure that has occurred is essential for:

Determining the type of seizure that has occurred is essential for:
 Focusing the diagnosis on particular aetiologies
 Selecting the appropriate therapy
 Providing potentially vital information on prognosis

13

Partial seizures

Simple partial seizures
Complex partial seizures
Partial seizures with secondary generalisations

14

Generalised Seizures

Absence seizures
Tonic-clonic seizures
Tonic seizures
Clonic seizures
Myoclonic seizures
Atonic seizures

15

Unclassified Seizures

Neonatal seizures
Infantile spasms

16

ILAE 2017 Classification of Seizure Types

ILAE 2017 Classification of Seizure Types
Based on 3 key features:
- Where seizures begin in the brain
- Level of awareness during the seizure
- Other features of the seizure

17

The clinical characteristics of a seizure will depend on:

The clinical characteristics of a seizure will depend on:
 Site of the focus
 Degree of ‘irritability’ of the areas of the brain surrounding the focus
 Intensity of the impulse

18

the desired outcomes in the treatment of epilepsy are:

The desired outcomes in the treatment of epilepsy are:  Absence of epileptic seizures
 Absence of anti-epileptic drug (AED)-related side effects
 Attainment of optimal quality-of-life

19

Treatment
General approach involves:

General approach involves:
 Identification of goals of therapy
 Must be patient-specific
 Goals may change with time

New-onset epilepsy
- Absence of seizures
- Absence of drug-related side effects
- Excellent quality of life

Chronic epilepsy
- Minimisation of incidence of seizures
- Alleviation of drug-related side effects
- Decent quality of life

20

Good and proper patient assessment
 Accurate diagnosis of seizure type determines initial choice of therapy

 Early treatment
- DECREASE in risk of seizure recurrence by 50%
 no effect on long-term prognosis

Good and proper patient assessment
 Accurate diagnosis of seizure type determines initial choice of therapy

 Early treatment
- DECREASE in risk of seizure recurrence by 50%
 no effect on long-term prognosis

21

what Patient-related factors also need to be considered when deciding on the tx

 Age
 Comorbid conditions
 Concomitant medications
 Risk of non-compliance to treatment or medications
 Family support
 Occupational/financial status

22

 Development of a care plan

Compare advantages and disadvantages of various anti-epileptic drugs

Monotherapy is ideal but combination therapy must be considered if monotherapy is inadequate

 Follow-up evaluation
Allows for re-assessment, updating and if necessary, revision of care plan

 Development of a care plan

Compare advantages and disadvantages of various anti-epileptic drugs

Monotherapy is ideal but combination therapy must be considered if monotherapy is inadequate

 Follow-up evaluation
Allows for re-assessment, updating and if necessary,

23

Non-Drug Treatment

Surgery
Dietary modification
compementary / alternative medicine
Vagus nerve stimulation

24

Surgery

 May be useful in up to 90% of patients with selected forms of epilepsy to achieve improvement of symptoms or seizure free status
 Usually advocated as early therapy for specific epileptic syndromes e.g.,
- Temporal lobe epilepsy with vs without mesial temporal sclerosis (70% vs 50%)
- Frontal lobe epilepsy with vs without identifiable lesion on MRI scan (50% vs 25%)

 Also considered as a last option (vs continued drug therapy) for certain refractory cases

25

Dietary modification

 Ketogenic diet may be used for patients who cannot tolerate or have not responded well to AED treatment

 Comprises low carbohydrate, high fat in diet
- induction of ketosis and production of decanoic acid
- decanoic acid associated with reduction in incidence of certain types of seizures or epileptic syndromes

 Supplemental vitamins/minerals (e.g., vitamin B, magnesium) may also sometimes be prescribed
- More useful in replacing any vitamins/minerals lost from the body due to the effects of AEDs (cf. seizure prophylaxis)

 Evidence is controversial
- More commonly prescribed in children
- Usually recommended if >2 different treatments have failed

26

Complementary/alternative medicine

 Should not be advised to the epileptic patient
 No evidence that acupuncture, chiropractic, herbal medicine, homeopathy, ostopathy, or yoga improve seizure control
 Drug interactions may give rise to changes in serum AED concentrations
- St John’s wort phenytoin / carbamazepine
 ? Evening primrose oil phenytoin / carbamazepine

 Some aromatherapy oils may produce an alerting effect on the brain --> increased risk of seizure
- Hyssop, rosemary, sweet fennel, sage, wormwood

27

Vagus nerve stimulation

 Indicated only for intractable partial seizures

 Electrodes attached around left branch of vagus nerve as well as connected to programmable stimulator  Stimulator delivers cyclical stimulation
 During a seizure, ‘on demand’ stimulation can be achieved by placing a magnet next to subcutaneously-implanted stimulator