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Yr 2 - Pharmacology > Epilepsy > Flashcards

Flashcards in Epilepsy Deck (92)
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1

What is epilepsy?

A group of neurological disorders marked by sudden and recurrent episodes of sensory disturbance, loss of conciousness or convulsions associated with abnormal electrical activity in the brain

2

On this pet scan which areas are coloured blue?(temporal lobe epilepsy)

The area of hypo-metabolism between seizures

3

How long between seizures in epilepsy?

It varies -> they are usually intermittent

4

What causes the seizures?

Excessive and abnormal cortical nerve cell activity

5

What 6 things can precipitate seizures?

- altered blood glucose and pH

- stress (going to dentist)

- fatigue

- flashing lights

- noise

- no apparent cause

6

How is epilepsy diagnosed (2)?

- ruling out other conditions that might cause similar symptoms

- confirmation with an electroencephalogram (EEG)

7

What are the major causes of epilepsy (10)?

- birth and perinatal injuries

- congenital malformations

- genetic (ion channels)

- idiopathic (unknown)

- Vascular insults

- Head trauma

- Severe metabolic disturbances

- drug/alcohol abuse

- Neoplasia

- Infection

8

What is the treatment when seizures are caused by something else i.e. tumours/infection?

Treat the underlying cause

NO ANTI-EPILEPTICS!!

9

What can epilepsy be confused with in children?

Febrile convulsion

(hyperthermia)

10

What are the NICE guidelines for epilepsy?

You must have 2 seizures and investigations prior to treatment

11

What are the two types of epilepsy?

Partial/focal/localised

Generalised/global

12

What are the different categories of localised seizures?

Simple (no loss of conciousness)

Complex (impairment of conciousness)

13

What are the different categories of Generalised seizures (6)?

Absence

Myclonic

Tonic clonic

Tonic

Atonic

Status epilepticus

14

What is a localised seizure?

It affects a specific region of a single hemisphere- includes psychomotor epilepsy

15

What % of seizures are accounted for by localised seizures?

60%

16

What can cause localised seizures?

Cortical lesions (tumours, developmental malformation, damage due to trauma or stroke)

Genetic

17

What are generalised seizures?

Discharges from both hemispheres

18

What % of seizures are accounted for by generalised seizures?

40%

19

What are generalised seizures often caused by?

Genetics

20

What are Absence seizures?

= look like daydreaming

21

What are Myclonic seizures?

= muscle twitch

22

What are Tonic clonic seizures?

= muscle convulsions

23

What are Tonic seizures?

= becoming stiff

24

What are Atonic seizures?

= drop seizures

25

What is Status epilepticus?

epileptic fits follow one another without recovery of conciousness between them

26

What are the two proposed mechanisms of epilepsy?

  1. Decreased inhibitory synaptic activity (insufficient GABA/ GABA-A receptor not working)
  2. increased excitatory synaptic activity (too much Glutamate (NMDA, Kainate or AMPA receptor)

27

What are the 3 proposed mechanisms for partial seizures?

  1. Selective loss of (inhibitory) interneurones = decreased feed forward/backward inhibiton of dendate gyrus cells
  2. Injury = synaptic reorganisation (axonal sprouting of remaining neurones) & recurrent excitatory connections
  3. Loss of excitatory neurones =usually inhibit dendate granule cells

28

What is an epileptic focus?

A high frequency burst of action potentials

(n.b. this is not a problem but its also not quite right)

29

How do epileptic foci develop into a seizure?

Hyper-synchronisation of neuronal populations = paroxysmal depolarising shift (PDS) = seizure

30

What is paroxysmal depolarising shift?

activation of AMPA (excitatory) receptors

-> e.g. by glutamate= NMDA receptor activation = increased intracellular K, accumulating Ca in pre-synaptic terminal (enhanced neurotransmitter release) & depolarisation induced NMDA receptor activation (increased Ca influx)