7) Epilepsy Flashcards
Epileptic seizure (definition)
= paroxysmal change in behaviour due to synchronised rhythmic firing of populations of CNS
Transient loss of conciousness due to
- epileptic seizures: acute- symptomatic OR unprovoked
- non-epileptic seizures
- unclear
Epilepsy (definition)
defined by recurrent unprovoked (=spontaneously occurring) seizures
Epidemiology
Prevalence
- approx. 70 Mio worldwide
- in Germany 5.5/1000 (around 450,000 patients, 22,000 in Berlin)
- acutal prevalence unknwon due to lack of diagnosis in rural areas
Life-time risk of one epileptic seizue
- 5 % of the general population
Age-dependent incidence
- epilepsy incidence higher in younger patients (until age of around 20) and in older adults (increase starting around the age of 60)
Epileptic seizure: epileptic - actue symptomatic
= provoked
- transient loss of consciousness
Triggers:
- acute brain lesion (eg intracranial bleeding, stroke, head trauma, infection)
- alcohol withdrawal
- metabolic disturbances (eg hypogycemia < 36mg/dl)
- intoxication (all ‘upper drugs’ such as MDMA)
- in children: fever > 35,8 °C
Non-epileptic seizure: non-epileptic
Differential diagnoses (epilepsy imitator)
- syncope
- dissociative seizure (PNEA)
- migraine with aura
- hypoglycaemic episode
- transient ischaemic attack (TIA)
Syncope vs tonic-clonic seizure (most prominent differences)
- duration: mostly < 30s – 1-2 min
- reorientation: < 30s – 4-45 min
Psychogenic non-epileptic seizure vs tonic-clonic seizure
- eyes: closed – open, deviation frequently
Epileptic seizure: epileptic - unprovoked: Epilepsy diagnosis
- two unprovoked seizures occurring > 24hrs apart
- one unprovoked seizure and a probability of further seizures similar to the general recurrence risk after two unprovoked seizures (at least 60%) over the next ten years
- causative CNS disease
- pathological EEG alternations
Classification of epileptic seizures - Focal onset
- initial symptoms/signs (clinical and EEG) indicate origin of seizure activity
- within an area of ONE hemisphere
Seizure types
- aware/impaired awareness
- Motor onset (automatisms, atonic, clonic, epileptic spasms, hyperkinetic, myoclonic, tonic)
- Non-motor onset (automatic, behaviour arrest, congitive, emotional, sensory)
focal to bilateral tonic-clonic
Localisation of focal aware seizures (= ‘aura’)
Distribution across brain areas
frontal lobe
- 25 %
- tonic/clonic movements
temporal lobe
- 65%
- lateral (10%)
- >auditory symptoms
mesial (90%)
- psychic or autonomic symptoms
parietal lobe
- 5%
- paraesthesia (abnormal sensation, tickling/pricking)
- vertigo
occipital lobe
- 5%
- visal symptoms
Classification of epileptic seizures - Generalised onset
- initial symptoms/signs (clinical and EEG) indicate origin of seizure activity
- simultaneously in BOTH hemispheres
Seizure types
- Motor (tonic-clonic, clonic, tonic, myclonic, myoclonic-tonic-clonic, myoclonic-atonic, atonic, epileptic spasms)
- Non-motor - absence (typical, atypical, myoclonic, eyelid myoclonia)
Overview Epilepsy classification
Seizure types
- focal
- generalised
- unknown
|
Epilepsy types
- focal
- generalised
- combined generalised & focal
- unknown
|
Leads to epilepsy syndomes
Co-morbidities can occur
Etiology
- structural
- genetic
- infectious
- metabolic
- immune
- unkown
Causes of focal onset epilepsy
- including all etiological causes (structural, genetic, infectious, metabolic, immune, unknown)
- Hippocampal sclerosis
- neuronal loss: CA1and CA4
- relative resistance: CA2 and CA3
- gliosis
- axonal and synaptic reorganisation - Malformation of cortical development (MCD)
2.1 Neuronal proliferation:
-> cortical dysplasia with ‘balloon cells’
-> hemimegalencephalia
2.2 neuronal migration:
-> heterotopias
-> lissencephaly/subcortical band-heterotopia spectrum
2.3 cortical organisation:
-> polymicrogyria
-> cortical dysplasia without ‘balloon cells’ - Vascular malformations
- (postnatal) acquired CNS lesions
- neoplasia
- cerebro-vascular
- traumatic brain injury
- neurodegeneration
- infectious/inflammatory
Causes of generalised epilepsy
Genetic (!) causes
Ion channel mutation
- Na+ channel
- K+ channel
- Cl- channel
Receptor mutation
- GABA receptor
- Acth - receptor
Ion transporter mutation
- Na+-K+-ATPase
Clincial features of psychogenic non-epileptic seizures
- undulating head movement
- eyes closed
- resistance on passive eye opening
- asynchonous movement
- long duration (> 2min)
- undulating movement of both extremities
Diagnostic
Standard Clinical Diagnostic
- MRI with epilepsy-specific protocoll (HARNESS)
- routine EEG with hyperventilation and photostimulation
Additional Clinical Diagnostic
- longterm video EEG (in Germany only as inpatient in few specialsied centres)
- neuropsychology
Treatment: Antiseizure Medication (ASM)
- pharmacotherapy surpresses the symptom
- the chronic disorder epilepsy cannot be modified or treated
- no anti-epileptogenic effects have been shown for current available ASM
- increase of ASM since 1980s
- target different neurotransmitter receptors
- few drugs reach 50% probability of seizure freedom with first drug regimen
- after that cummulative effects
- and pharmacoresistance with later antiepileptic durg regimen
Treatment goal in chronic epilepsy
maintenance of normal life style
- complete seizure freedom
+
- no or minimal substance adverse effects
Treatment success of ASM
60%
- good prognosis
- seizure-free with first or second monotherapy
- no relevant adverse effects
- commonly seizure-free with AED termination
30%
- pharmacoresistant with polytherapy
10%
- seizure-free with polytherapy
Epilepsy surgery - Eligibility criteria
- pharmacoresistance
- identification of one epilelptic focus with EEG
-suitable MRI lesion - resection possible without persistent neurological/neuropsychological deficits
Epilepsy surgery - Resective epilepsy surgery
Temporal lobe (hippocampal sclerosis)
- resection of amygdala, hippocampus, temporo-basal structures
- significant reduction of seizure frequency and 55% seizure-freedom 2 years after TL-resection
Epilepsy surgery - laser treatment
MRI guided
- in mesial temporal lobe epilepsy 62% (total) efficacy
Unreceived epilepsy surgery
- increase in rejection rate
- decrease in sugery
- increase in contraindication (no resection)
- 57% patients not referred
- 70% of the referred patients refused
- 5 % of referred patients agreed to evaluation but did not schedule appointment
- 10% of referred patients scheduled appointment for evaluation
- reluctance by epileptologists and patients
Syncope vs tonic-clonic seizure
Syncope vs tonic-clonic seizure (most prominent differences)
- duration: mostly < 30s – 1-2 min
- reorientation: < 30s – 4-45 min
Psychogenic non-epileptic seizure vs tonic-clonic seizures
Psychogenic non-epileptic seizure vs tonic-clonic seizure
- eyes: closed (in almost all cases) – open (in most cases)
