Having considered the factors that can, can lead to alterations in network
excitability I'm ready to cover the
definition of the other two important terms.
So, so the first one is epilepsy. When we use the term epilepsy, we mean
that we determine that the patient has a tendency towards recurrent seizures.
Now importantly, what this means is that if a person has an
individual seizure, a single seizure it
doesn't mean that they necessarily have epilepsy.
Its only if they have recurrent seizures or the
circumstances are such that we conclude that there's a very,
very high likelihood of having recurrence that we use the term epilepsy.
And I think it's really important to be clear
about the difference between the term seizure and epilepsy.
Because epilepsy, in particular, is still associated with a great amount of stigma.
Something that we really need to try and remove worldwide.
But it's a term that should really be
designated only for the person who has the more
chronic condition of a tendency for having recurrent seizures.
And then the third term is
epileptogenesis, and that's the sequence of
events that takes a normal network, and turns it into the hyperexcitable network.
And in the previous slide we covered
some of the different characteristics that could
be altered, say from a genetic point of view or from trauma and so forth.
That could, that could cause epileptogenesis.
Now that leads of course to what the different causes are, of epilepsy.
And I've listed them, in a very, very short list here.
We're going to return to this when we talk about
the, evaluation of a patient, with seizures and epilepsy.
But just as, just to give you a sense on brain injury.
Someone who has had trauma or stroke, you could imagine how
that could change the intrinsic properties of individual cells or alter
the way they're connected together leading to hyper excitability.
Same thing with tumor, the effects of a tumor either the, the, the molecules that
it produces in a neighboring region or the scaring that's created in in the brain.
Or other factors can lead to hyper excitability.
Genetics, a very important cause of seizures and epilepsy.
Imagine if the the, the gene
coding an individual ion channel leads to a significant change in its
function so that, for example, much more sodium is flowing into the cell.
Giving rise to more depolarization of an excitatory neuron.
This would be a cause of epilepsy.
Developmental abnormalities in the way the brain has developed in
utero can lead to an altered network and hyper excitability.
Infection and the inflammatory factors
that are associated with that can lead to hyper excitability.
And finally, a whole variety of
both endogenous and exogenous metabolic changes which
again would effect the properties of the brain giving rise to hyper excitability.