Integration of Data for Pre-Surgical Evaluation Flashcards
What is a seizure?
An epileptic seizure is a transient occurence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain
What did John Hughlings Jackson describe?
Epilepsy is the name for occasional, sudden, excessive, rapid and local discharges of grey matter
What is epilepsy?
2005: disorder of the brain characterised by an enduring predisposition to generate epileptic seizures. Two unprovoked seizures > 24 h apart
What is the 2014 updated practical definition of epilepsy?
- At least two unprovoked seizures occurring >24 h apart
- One unprovoked seizure and a high probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occupying over the next 10 years
- Diagnosis of an epilepsy syndrome
What is the epilepsy of epilepsy?
- Epilepsy is common
- Incidence = no. of new cases/time (year)/population
- Epilepsy 50-70 per 100,000 (developed countries)
- Parkinson’s disease: 12 per 100,000
- Multiple sclerosis: 7 per 100,000
- Bimodal peak incidence
Why epilepsy is important?
• Commonest serious disorder of the brain
• Prevalence (no. of cases at a given time/population) in the UK = 1:131
• Lifetime risk of having a seizure is ~5%
• High rate of misdiagnosis
• Epilepsy is treatable
- 2 in 3 people respond to antiepileptic medication
- In temporal lobe epilepsy, 70-80% can become seizure free with surgery
What are two classification types of epilepsy?
- Generalised
2. Focal
What is generalised epilepsy?
The abnormal electrical discharge involves both sides of the brain at the same time
What is focal epilepsy?
The abnormal electrical discharge starts in one area of brain and spreads from there
What is the Epileptogenic zone?
- Patient with focal onset and are not responding to medications – tried 2 anti-seizure medication and they haven’t worked – they are considered pharmaco-resistant or intractable
- We want to look for other options for treatment – epilepsy surgery
- Region of cortex that generates epileptic seizures
- By definition total removal or disconnection of this area is necessary and sufficient for seizure freedom
What is semiology?
- The study of objective signs and (subjective) symptoms during a seizure
- Gives important information about the anatomical area(s) of cortex activated during a seizure
- Often entire networks are activated, causing complex behavioural phenomena during seizures
- We assume that the area of seizure onset (ictal onset zone) is close by/connected with these areas
What is the beginnings of Epilepsy Surgery?
- Patient James B., 22 y/o
- Seizure onset: age 15 years
- Aetiology: severe head injury in road traffic accident at age 7 years
- Child admitted to Edinburgh Royal infirmary, depressed skull fx was debridedm
The first epilepsy operation - Sir Victor Horsley FRS
- May 25th 1886, in the ward day room at the National Hospital
- The patient had 2870 seizures in the prior 13 days
- Surgery was based on the principles of clionical-anatomical localisation by Jackson
- Intraoperatively, cortical scar was ‘‘very apparent, highly vascular, measuring 3 by 2cm’’
- It was removed with half a centrimetre of surrounding brain substance.
- Outcome ‘‘There were no more fits’’
What are other important definitions?
- Symptomatogenic zone
- Epileptognic lesion
- Eloquent cortex
What is symptomatogenic zone?
- Area of cortex that is generating symptoms during the seizure
