Large range of conditions characterised by recurrent unprovoked epileptic seizures
A group of neurological diseases with enduring alterations in the brain resulting in abnormally increased predisposition to seizures
What do the clinical manifestations of epilepsy arise from?
Paroxysmal excessive, synchronous, abnormal firing patterns of neurons
Describe the lifetime prevalence of seizures?
9% of people will have a seizure at some stage in their life
Describe the lifetime incidence of epilepsy?
2-4% of people will develop epilepsy
What is the most common serious chronic neurologic condition?
What is the point prevalence of epilepsy?
0.5-1% of people have active epilepsy at any one point in time
In which populations is epilepsy more prevalent?
Lower socioeconomic groups
Describe the groups of adverse consequences associated with epilepsy?
Physical morbidity: injury, cognitive, medical
Psychiatric morbidity: high rates of depression, anxiety and psychosis
Social morbidity: restrictions of having epilepsy, prejudice
Medication side effects
Describe the mortality ratio for epilepsy?
Standardised mortality ratio is approximately 3.0 vs general population
Higher in symptomatic vs idiopathic epilepsies
What are the major causes of death associated with epilepsy?
What is SUDEP?
Sudden unexplained death in epilepsy
Epileptics found dead, with no explanation
Could be direct consequence of seizure, but mechanism is unknown
In which population is SUDEP significant?
Most common cause of death in young people with epilepsy
Define an epileptic seizure?
Transient occurrence of clinical signs and/or symptoms due to excessive and hyper-synchronous activity of populations of neurons in the brain
Groupd of neurons that usually fire individually get into a loop and fire as a group, with recurrent activation
What determines the clinical manifestations of epilepsy?
The region of the brain involved in the seizure, at onset and from secondary spread
What are the three major groups of causes of epilepsy?
Describe the ILAE classification of seizures and epilepsy?
Seizures: based on clinical features and EEG findings
Epilepsies and epileptic syndromes: epileptic disorders with similar signs, symptoms, prognosis and response to treatment
Describe the ILAE classification of seizures?
Partial/focal seizures: arise in a limited number of cortical neurones within one hemisphere
Generalised seizures: appear to arise simultaneously in both hemispheres
What is the most common cause of partial/focal seizures?
Structural or metabolic abnormalities
When does epilepsy due to genetic causes usually arise?
Does epilepsy often remit?
Often remits if due to genetic causes
Rarely remits if due to structural or metabolic causes
Which causes of epilepsy are well controlled with medication?
Genetic usually controlled
Structural or metabolic often incompletely controlled
When does epilepsy due to a structural or metabolic abnormality usually arise?
More common with age >20
Major cause in elderly patients
Why is diagnosis of epilepsy so important?
Prognosis: treatment response, likelihood of remission, development of co-morbidities
Treatment: medical and surgical
What is the current idea of the cause of epilepsy?
Disturbance in the balance between inhibition and excitation of cortical neurones and neuronal networks
Results in neuronal networks that fire in an uncontrolled, hyper-synchronous, self-sustained manner
Descibe the alterations in neuronal networks that may occur in epilepsy?
Loss of inhibitory neurons
Gain of excitatory neurons (neurogenesis - brain tries to repair itself after injury)
Alterations in intrinsic neuronal cellular excitability
Alterations in synaptic transmission
Alterations in the extra-neuronal environment
Which is the most sensitive brain stucture to induce seizure activity?
(in picture, the epileptic hippocampus on the left is amller than the control on the right)
Desribe the circuitry of the hippocampus?
EC > DG > CA3 > CA1 > EC
Which disease process in the hippocampus most commonly leads to epilepsy?
Mesial temporal sclerosis
Describe the relationship between epileptogensis and disease progression?
Changes continue to evolve as disease becomes chronic
Seizures themselves accelerate changes and lead to the development of more seizures
What are the markers of disease progression in epilepsy?