The Neurological and Cellular Basis of Epilepsy

Question 1

What is epilepsy?

Answer 1

conditions characterised by recurrent unprovoked epileptic seizures due to excessive, synchronous and abnormal firing of neurons

Question 2

What adverse consequences are associated with epilepsy?

Answer 2

injury, psychiatric morbidity (depression, anxiety, psychosis), social morbidity (inability to drive, inability to work, prejudice), medication side effects, mortality

Question 3

What may cause mortality in epilepsy?

Answer 3

injury, drowning, asphyxia, status epilepticus, suicide, sudden unexplained death in epilepsy

Question 4

What are the three types of epilepsy?

Answer 4

genetic, structural/metabolic and unknown

Question 5

Which type of epilepsy is often difficult to control with medication?

Answer 5

structural/metabolic

Question 6

Which age group is most commonly affected by genetic epilepsies?

Answer 6

children and teenagers

Question 7

Why is it important to diagnose which type of epilepsy it is?

Answer 7

for prognosis, treatment options and genetic implications

Question 8

When is surgery a suitable treatment for epilepsy?

Answer 8

if the epilepsy is focal from a well defined area that can be safely excised - most commonly due to a structural/metabolic type epilepsy

Question 9

What are the three types of seizures?

Answer 9

partial/focal, generalised and unclassifiable

Question 10

What causes epilepsy?

Answer 10

genetic factors, congenital factors, trauma, infections, metabolic factors, drugs

Question 11

What types of neuronal changes may lead to epilepsy?

Answer 11

alterations in neuronal networks, alterations in intrinsic neuron excitability, alterations in synaptic transmission

Question 12

What types of alterations in neuronal networks may lead to epilepsy?

Answer 12

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)

Question 13

What types of alterations in intrinsic neuronal excitability may lead to epilepsy?

Answer 13

change in expression of ion channels

Question 14

What extra neuronal changes may lead to epilepsy?

Answer 14

alterations in glia function

Question 15

Which part of the brain is the most sensitive for developing an epileptic network?

Answer 15

the hippocampus

Question 16

What is the most common cause of drug resistant temporal lobe epilepsy?

Answer 16

hippocampal sclerosis

Question 17

What histopathology is seen in hippocampal sclerosis?

Answer 17

cell loss, mossy fibre sprouting, gliosis

Question 18

What is the relationship between seizures and epileptogesis?

Answer 18

seizures accelerate the neuronal changes and make the seizures more likely to occur

Question 19

When is epilepsy onset most common?

Answer 19

in young people and in old people

Question 20

What type of genes are involved in genetic epilepsies?

Answer 20

voltage gated ion channels, ligand gated ion channels and non ion channels e.g. GLUT1

Question 21

What types of pathology may underly a drug resistant focal epilepsy?

Answer 21

mesial temporal sclerosis, malformation of cortical development, low grade tumours, vascular malformations, encephalomalacia (focal lesions from previous insults e.g. stroke, infection, trauma)

Question 22

What are the MRI features of mesial temporal sclerosis?

Answer 22

hippocampal atrophy, increased T2 signal, decreased T1 signal, loss of internal architecture

Question 23

What are the MRI features of focal cortical dysplasia?

Answer 23

focal thickening of the cerebral cortex, blurring of grey/white interface, gyral abnormalities, region of increased T2 signal

Question 24

What is the most common cause of new onset partial seizures in the 35-55 age group?

Answer 24

tumour

Question 25

What type of vascular lesions can cause epilepsy?

Answer 25

cavernomas, arteriovenous malformations

Question 26

What is the treatment for epilepsy?

Answer 26

drugs which decrease frequency or severity of seizures, surgery, neurostimulators, diet