The Neurological and Cellular Basis of Epilepsy Flashcards
What is epilepsy?
conditions characterised by recurrent unprovoked epileptic seizures due to excessive, synchronous and abnormal firing of neurons
What adverse consequences are associated with epilepsy?
injury, psychiatric morbidity (depression, anxiety, psychosis), social morbidity (inability to drive, inability to work, prejudice), medication side effects, mortality
What may cause mortality in epilepsy?
injury, drowning, asphyxia, status epilepticus, suicide, sudden unexplained death in epilepsy
What are the three types of epilepsy?
genetic, structural/metabolic and unknown
Which type of epilepsy is often difficult to control with medication?
structural/metabolic
Which age group is most commonly affected by genetic epilepsies?
children and teenagers
Why is it important to diagnose which type of epilepsy it is?
for prognosis, treatment options and genetic implications
When is surgery a suitable treatment for epilepsy?
if the epilepsy is focal from a well defined area that can be safely excised - most commonly due to a structural/metabolic type epilepsy
What are the three types of seizures?
partial/focal, generalised and unclassifiable
What causes epilepsy?
genetic factors, congenital factors, trauma, infections, metabolic factors, drugs
What types of neuronal changes may lead to epilepsy?
alterations in neuronal networks, alterations in intrinsic neuron excitability, alterations in synaptic transmission
What types of alterations in neuronal networks may lead to epilepsy?
loss of inhibitory neurons, gain of excitatory neurons (when brain tries to regenerate after injury) or aberrant sprouting (when axon tries to reconnect after injury)
What types of alterations in intrinsic neuronal excitability may lead to epilepsy?
change in expression of ion channels
What extra neuronal changes may lead to epilepsy?
alterations in glia function
Which part of the brain is the most sensitive for developing an epileptic network?
the hippocampus
What is the most common cause of drug resistant temporal lobe epilepsy?
hippocampal sclerosis
What histopathology is seen in hippocampal sclerosis?
cell loss, mossy fibre sprouting, gliosis
What is the relationship between seizures and epileptogesis?
seizures accelerate the neuronal changes and make the seizures more likely to occur
When is epilepsy onset most common?
in young people and in old people
What type of genes are involved in genetic epilepsies?
voltage gated ion channels, ligand gated ion channels and non ion channels e.g. GLUT1
What types of pathology may underly a drug resistant focal epilepsy?
mesial temporal sclerosis, malformation of cortical development, low grade tumours, vascular malformations, encephalomalacia (focal lesions from previous insults e.g. stroke, infection, trauma)
What are the MRI features of mesial temporal sclerosis?
hippocampal atrophy, increased T2 signal, decreased T1 signal, loss of internal architecture
What are the MRI features of focal cortical dysplasia?
focal thickening of the cerebral cortex, blurring of grey/white interface, gyral abnormalities, region of increased T2 signal
What is the most common cause of new onset partial seizures in the 35-55 age group?
tumour
What type of vascular lesions can cause epilepsy?
cavernomas, arteriovenous malformations
What is the treatment for epilepsy?
drugs which decrease frequency or severity of seizures, surgery, neurostimulators, diet
