Epilepsy Flashcards
Define: Seizure, Epilepsy, Status Epilepticus
Seizure - sudden surge of electrical activity in the brain (sensory disturbance, loss of consciousness, convulsions, abnormal brain activity)
Epilepsy - neurological disorder characterised by recurrent episodes of seizures
Status Epilepticus - continuous seizure activity or repetitive seizures without regaining consciousness
What’re Jacksonian seizures?
Abnormal electrical activity in localised area of the brain - type of partial seizure
Motor: begins in one group of muscles and progresses to adjacent muscle groups usually distal -> proximal
Sensory: again short lasting activity that spreads
Typically through limbs and trunk
How is epileptiform activity characterised?
Prolonged large amplitude, synchronous cortical activity (ictal) with interspersed low-activity periods (inter-ictal)
What are the symptoms of epilepsy?
Varied according to focus and spread
May be preceded by auras/hallucinations and often followed by drowsiness
Where would the focal site be of seizures preceded by auras/deja vu or motor disturbances?
Temporal lobe
Frontal lobe
How are the different types of epilepsy newly classified?
Based on where seizures begin, the level of awareness and other features eg motor or auras
What are the classifications of epilepsy?
FOCAL: Aware / Impaired awareness / Motor / Non-Motor
FOCAL TO BILATERAL
GENERALISED: Motor / Non-Motor (impaired awareness assumed)
UNKNOWN ONSET - can still describe where motor/non-motor
+ Auras ?
What’s antiepileptic hypersensitivity syndrome?
Major side effect of AEDs usually 1-8 weeks after treatment
Need to withdraw AED immediately but beware of rebound seizures, and use topical steroid + antihistamines
Initial signs: fever, rash, lymph node swelling
Severe signs: blood, liver, kidney, respiratory abnormalities, vasculitis and organ failure
What’s NEAD and in what ways is it different to normal seizures?
Non epileptiform attack disorder (psychogenic seizures) = no physical reason or changes in brain activity but similar symptoms
Diagnose by EEG
Differences in tongue biting (usually tip of tongue whereas general seizures bite sides), eye opening (usually held shut), duration, recollection
What’s the basis of an EEG?
Records voltage deflections relative to ground electrode, usually the ear
Focus of activity easy to pinpoint and may correlate to symptoms/auras
Records levels of synchrony between neurones - those firing together will show larger amplitude oscillations
What are the 5 different types of rhythms seen on EEG?
Delta <3.5 Hz deep sleep/coma
Theta 4-7 Hz parietal and temporal lobes, alertness
Alpha 8-13 Hz occipital lobes, quietness, eyes shut
Beta >14 Hz parietal and frontal lobes, activity, tension, sleep spindles
Gamma >40 Hz learning and memory
What changes in neuronal excitability occur in epileptiform activity?
Reduction in GABA
Reduction in K+ channel activity
Increase in ACh transmission
Increase in Na+ channel activity
What channelopathies can occur in epilepsy?
Mutations often linked to congenital forms
K+, Na+, ACh, GABA receptors
GABA mutations in idiopathic generalised and juvenile myoclonic
SCN1B/1A in severe myoclonic infancy
CHRNA4/B2 in ACh receptors in autosomal dominant nocturnal frontal lobe epilepsy
Outline the treatment for epilepsy (pharmacological, surgical, implants)
Pharmacological AEDs: Na+ channel blockers, Ca2+ channel blockers, GABA modulation/mimetics
Surgical: removal of aberrant areas
Impants: DBS or VNS (vagal nerve stimulation)
What are routes to achieve GABA activity enhancement?
Co-agonist sites
Inhibition of GABA breakdown
Inhibition of GABA reuptake
GABAmimetics
