What are seizures
abnormal paroxysmal changes in the electrical activity of the brain, they reflect large scale synchronous discharges of neuronal networks
What is epileptogensis
the process by which normal brain function progresses towards generation of abnormal electrical activity
What is epilepsy
a neurological disorder that represents a brain state that supports recurrent, unprovoked seizures
describe the prevelance of epilepsy
Prevalence in the UK is 1%
65 million people worldwide
A third of patients are resistant to treatment
What is the difference between generalised seizures and focal seizures
Generalised
- both hemispheres are affected and this is always associated with loss of awareness
Focal
- limit to one hemisphere and then further divided into whether or not there is los of awareness
What are the classification of seizures
What is status epileptics
– a form of epilepsy which is a life threatening medical emergency, seizures which last more than 5 minutes ( or more than a seizure in 5 minutes, without regain of consciousness)
describe what happens in a petit mal seizure
=begins in childhood.
= Loss of awareness and a vacant expression for <10 seconds before returning abruptly to normal and continuing as though nothing had happened.
= Apart from slight fluttering of the eyelids there are no motor manifestations.
= Patients often do not realize they have had an attack but may have many per day
What happens in a clonic seizure
= these are rarer
= there are rapidly alternating contraction and relaxation of a muscle = jerking
what is jerking
alternating contration and relaxation of a muscle
what is another term for grand mal seizures
tonic clonic seizures
what is another word for absent seizures
petit mal
name the phases of a grand mal seizure
= premonition = pre-tonic clonic phase = tonic phase = clonic phase = postictal period
describe the phases of a grand mal seizure
What is an atonic seizure
(decrease in tone) brief lapse in muscle tone causing fall
what is a myoclonic seizure
momentary brief contractions of a muscle or muscle groups, e.g. causing a sudden involuntary twitch of a finger or hand.
name some generalised seizures
How do you diagnose epilepsy
describe the causes of epilepsy at different age groups
Children and teenagers = genetic, perinatal and congenital disorders
Young adults = trauma, drugs, alcohol
> 60 = cerebrovascular disease, neoplasms
what can cause temporal lobe epilepsy and is also a major cause of epilepsy
= Hippocampal sclerosis (damage with scarring and atrophy of the hippocampus and surrounding cortex) is a major cause of epilepsy (temporal lobe epilepsy).
= Usually visible on MRI and may be amenable to surgical resection of the damaged temporal lobe.
= there is loss of cells in the CA2 and CA3 hippocampal areas.
= there may be Sprouting of the mossy fibres of granule cells which may lead to reverberant excitatory circuits.
= Neurogenesis may also occur which can lead to abnormal circuits.
What is hippocampus sclerosis
= Hippocampal sclerosis (damage with scarring and atrophy of the hippocampus and surrounding cortex) is a major cause of epilepsy (temporal lobe epilepsy).
what are two things that can cause primary epilepsy
= hippocampal sclerosis
= loss of chandelier cells
What are chandelier cells
= the are a special population of GABAergic cortical interneurones in the CNS that can control the activity of cortical pyramidal cells
what happens when there is loss of chandelier cells
this increases the risk of abnormal excitatory activity and epilepsy