Cellular Basis of Epilepsy Flashcards Preview

MD1 Neuroscience > Cellular Basis of Epilepsy > Flashcards

Flashcards in Cellular Basis of Epilepsy Deck (57):
1

What is epilepsy?

Large range of conditions characterised by recurrent unprovoked epileptic seizures

2

What does the clinical presentation of epilepsy result from?

Paroxysmal excessive, synchronous, abnormal firing patterns of neurons

3

What does the specific presentation of epilepsy depend on?

Which part of brain affected

4

What is the most common serious chronic neurological condition?

Epilepsy

5

What is the epidemiology of epilepsy?

Affects all societies and strata, globally
Increased in underdeveloped countries and lower SE groups

6

Why is the prevalence of epilepsy higher in underdeveloped countries and lower SE groups?

Primarily because people in this group develop more conditions that injure their brain > seizures

7

What are the significant adverse consequences of epilepsy?

Physical morbidity
Psychiatric morbidity
Social morbidity
Medication side effects
Mortality

8

What is an epileptic seizure?

Transient occurrence of clinical signs and/or symptoms due to excessive and hyper-synchronous activity of populations of neurons in brain

9

Does everyone have the same sort of seizure?

No, seizures vary from person-person and type-type

10

What are the different categories of epilepsy?

Genetic = idiopathic/primary
Structural/metabolic = symptomatic/secondary
Unknown = cryptogenic

11

What is the classification of the type of epilepsy based on?

Similar
- Signs
- Symptoms
- Prognosis
- Response to treatment

12

Why is it important to classify the type of epilepsy a person has?

Choosing treatment options
Counselling patients regarding
- Aetiology
- Genetics
- Likely prognosis

13

What is a partial (focal) seizure?

Arise in limited number of cortical neurons in one hemisphere

14

What is usually the cause of a focal seizure?

Focal brain lesion

15

Are focal seizures easy to control?

No, tend to be more difficult to control

16

What is a generalised seizure?

Arise simultaneously in both hemispheres

17

What is usually the cause of a generalised seizure?

Genetic

18

What is genetic (idiopathic) epilepsy?

Underlying brain structurally and functionally normal

19

When is the usual onset in genetic epilepsy?

Childhood/teenage

20

Can genetic epilepsy remit?

Possible

21

Does genetic epilepsy respond well to medication?

Yes

22

What is structural/metabolic (symptomatic) epilepsy?

Seizures result from identifiable structural/functional brain abnormality

23

Does structural/metabolic epilepsy remit?

Not commonly, because brain injury doesn't go away

24

Does structural/metabolic epilepsy respond well to medication?

Incompletely controlled

25

What causes epilepsy?

Disturbance in balance between inhibition and excitation of cortical neurons and neuronal networks

26

What does the imbalance between excitation and inhibition of neurons cause?

Neuronal networks fire in uncontrolled, hyper-synchronous, self-sustained way

27

What are the possible causes of the imbalance between excitation and inhibition of neurons?

Genetic
Congenital/developmental
Traumatic
Infectious
Metabolic
Drugs

28

What can alter in neuronal network components to produce epileptic neuronal networks?

Loss of inhibitory neurons
Gain of excitatory neurons via neurogenesis - often happens after brain injury
Aberrant sprouting - can often sprout back on themselves creating auto-excitation

29

What are the mechanisms by which epileptic neuronal networks are generated?

Alterations in neuronal network parts
Alterations in intrinsic neuronal cellular excitability
Alterations in synaptic transmission
Alterations in extra-neuronal environment

30

What is the most sensitive structure to induce seizure activity?

Hippocampus

31

What is the epileptic remodelling that takes place in the hippocampus?

Cell loss
Mossy fibre sprouting
Gliosis

32

What is the relationship between epileptogenesis and disease progression?

Seizures beget seizures

33

What is the disease progression of epilepsy?

Drug resistance
Neuronal loss
Synaptic reorganisation
Neurocognitive changes
Psychiatric changes

34

When is the onset of epilepsy?

Common at all ages
Peaks in young and old

35

What is the aetiology of new onset epilepsy in infancy and early childhood?

Most commonly congenital or perinatal CNS insults

36

What is the aetiology of new onset epilepsy in late childhood and early adulthood?

Most commonly idiopathic/genetic

37

What is the aetiology of new onset epilepsy in adulthood and the elderly?

Most symptomatic
- Trauma
- Ischaemia
- Tumours
- Haemorrhange
- Degenerative diseases

38

What is the cause of genetic epilepsies?

5-10% Mendelian monogenic inheritance pattern
Most have complex inheritance patterns

39

How are pathologies of the brain identified in focal epilepsy?

MRI

40

What is the most common pathology in adults with partial epilepsy?

Mesial temporal sclerosis

41

What is the prognosis of epilepsy when the pathology is mesial temporal sclerosis?

Most patients continue to have seizures despite medication
Good prognosis with surgery

42

What are the MRI features of partial epilepsy with a pathology of mesial temporal sclerosis?

Unilateral hippocampal atrophy
Increased T2 signal
Decreased T1 signal
Loss of internal architecture

43

What is focal cortical dysplasia?

Focal regions of disturbed cortical development and architecture

44

What is the aetiology of focal cortical dysplasia?

Uncertain

45

What are the MIR features of focal cortical dysplasia?

Focal thickening of cerebral cortex
Blurring of grey/white interface
Gyral abnormalities
May be associated with region of increased T2 signal

46

What is the prognosis of focal cortical dysplasia?

Almost always drug resistant
If focal, respond well to surgery

47

What is periventricular nodular heterotopia?

Generalised malformation due to abnormal neuronal migration
Nodular masses of grey matter diffusely lining ventricular walls
- Bilateral or focal

48

What is the cortical and neurological functioning like in periventricular nodular heterotopia?

Normal

49

What proportion of people with partial epilepsy have low grade tumours?

15%

50

What proportion of people with chronic drug resistant partial epilepsy have vascular lesions?

10%

51

What is focal encephalomalacia?

Focal lesion from previous destructive insult, especially
- Trauma
- Stroke
- Infection

52

What are the MRI features of focal encephalomalacia?

Irregular area of atrophy of cerebral cortex and underlying white matter
Surrounding region of increased T2 signal
May be associated with large cystic region

53

What are anti-epileptic drugs?

Decrease frequency and/or severity of seizures in people with epilepsy

54

Do anti-epileptic drugs treat the underlying epileptic condition?

No, treat symptoms; ie: seizures

55

What proportion of people have drug resistant epilepsy?

30%

56

What are non-medical treatments for epilepsy?

Often adjunct to medications
Surgery
Neurostimulators
Dietary

57

What kinds of epilepsy can be treated with surgery?

Focal epilepsy where origin of seizures can be localised to brain region that can be resected with low risk of significant damage afterwards

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