Epilepsy

Question 1

Define seizure (3)

Answer 1

A sudden irregular discharge of electrical activity in the brain causing a sensory disturbance, unconsciousness or convulsions.

Question 2

Define convulsion. (2)

Answer 2

Uncontrolled, shaking movements due to rapid muscle contraction and relaxation.

Question 3

Define aura. (2)

Answer 3

A perceptual disturbance experienced prior to a neurological event eg seizure, migraine.

Question 4

Define epilepsy. (3)

Answer 4

A neurological disorder characterised by recurrent episodes of LoC, sensory disturbance, or convulsions associated with abnormal electrical activity.

Question 5

Define status epilepticus. (3)

Answer 5

Epileptic seizures occurring continuously without the regain of consciousness in between. A medical emergency as it can remove the patients ability to breathe.

Question 6

Describe the two main types of seizures. (2)

Answer 6

Partial - involving a focal portion of the brain.

Generalised - involving diffuse areas of the brain.

Question 7

Describe the types of partial seizure. (2)

Answer 7

Simple - consciousness maintained

Complex - consciousness impaired.

Question 8

Describe the two most common types of partial seizure. (7)

Answer 8

Temporal lobe is most common, often following brain injury, often presents before 20 years, and is commonly seen with clothes plucking and lips smacking.
Frontal lobe is the next common, presenting its abnormal motor signs on the contralateral side to the seizure.

Question 9

Describe the types of generalised seizure. (10)

Answer 9

Atonic - sudden loss of tone - “drop attack”
Tonic - sudden increase in tone
Myoclonic - shock like muscle jerks (no increase in tone)
Tonic-clonic - 1st tonic (increase tone) then clonic (convulsions)
Abscence - “daydreaming”

Question 10

Describe the investigation you would perform on a patient presenting with seizures. (4)

Answer 10

EEG
MRI
ECG
Bloods

Question 11

Describe the questions you would ask when taking a history about the time immediately prior to the seizures. (9)

Answer 11

PMH - trauma, brain disease
FH - epilepsy
Triggers - strobe lighting 
Aura - sights, smells
First signs or symtoms

Question 12

Describe the questions you would ask when taking a history about the seizure itself. Who old you need to get this history from? (7)

Answer 12

Description - tone, movements
Duration
Self resolving
Abrupt or gradual end 
Needs a collateral history

Question 13

Describe the questions you would ask when taking a history about the time directly after the seizure. (4)

Answer 13

Post-ictal state - groggy?
Tongue biting
Incontinence
Neurological deficits - stroke?

Question 14

Describe causes of secondary epilepsy. (13)

Answer 14

Vascular - stroke, TIA 
Infection - meningitis, abscess
Trauma - intercerebral haemorrhage 
Autoimmune - SLE 
Metabolic - hypoxia, hypoglycaemia, hyponatraemia, thyroid dysfunction. 
Iatrogenic - drugs, alcohol withdrawal 
Neoplastic - intercerebral mass.

Question 15

Explain the purpose of performing an EEG, and how it would help. (3)
Explain what you would do if the history indicated epilepsy but the initial EEG was inconclusive. (3)

Answer 15

An EEG is taken to support a clinical history suggestive of epilepsy. Light stimulation and hyperventilation are employed to induce a seizure.
Can’t do with risk of syncope (false positive).
Consider repeated EEGs, sleep EEGs, ambulatory EEGs.

Question 16

Explain the mechanism of action of sodium channel blockers for treating epilepsy. (2)
Give 5 examples of sodium channel blockers. (5)

Answer 16

Caused Na+ channels to remain in an inactive state to prevent action potentials from firing repeatedly.
Carbamazepine, lamotrigine, sodium valproate, phenytoin, topiramate.

Question 17

Explain the mechanism of action of calcium channel blockers for treating epilepsy. (3)
Give 2 examples of calcium channel blockers. (2)

Answer 17

Prevents activity of calcium channels to prevent the depolarisation that causes the classic waveform patterns seen in abscence seizures.
Ethosuximide, sodium valproate.

Question 18

Explain the mechanism of action of GABA potentiators in treating epilepsy. (1)
Give 2 examples of GABA potentiators. (2)

Answer 18

Enhance the inhibitory effects of GABA at the synapse.

Barbiturates, benzodiazepines.

Question 19

Explain the mechanism of action of GABA transaminase inhibitors in treating epilepsy. (2)
Give 1 example of a GABA transaminase inhibitor. (1)

Answer 19

Prevent the breakdown of GABA to increase its inhibitory action at synapses.
Vigabatrin

Question 20

Explain the mechanism of action of Gabapentin. (2)

Answer 20

Increases GABA production so increases the inhibitory effect at synapses.

Question 21

Explain the mechanism of action of Levetiracetam. (3)

Answer 21

Binds to synaptic vesicles to inhibit the release of neurotransmitters even if there is calcium channel action. Inhibitory on the synaptic transmission.

Question 22

Describe 4 side effects of all antiepileptics.

Answer 22

Dizziness
Fatigue
Diplopia
Ataxia

Question 23

Describe 2 side effects of Gabapentin.

Answer 23

Irritability and behaviour change

Weight gain.

Question 24

Describe 3 side effects of Topiramate.

Answer 24

Weight loss
Metabolic acidosis
Language dysfunction

Question 25

Describe two side effects of Lamotrigine.

Answer 25

Tics

Insomnia

Question 26

Describe the diagnostic criteria for starting antiepileptic drugs. (6)

Answer 26

First unprovoked seizure and one of:
Neurological deficit occurs / worsens after seizure
EEG shows unequivocal epileptic activity
Risk of further seizure is unacceptable (eg with work etc)
Imaging reveals structural abnormality (makes recurrence more likely)
More than one seizure type occurs.

Question 27

Describe the considerations of pregnancy and AEDs. (8)

Describe how you would combat these in a severely epileptic and pregnancy woman. (3)

Answer 27

Many antiepileptics are highly teratogenic, especially sodium valproate (causes decreased serum folate leading to neural tube and craniofacial defects), carbamazepine (neural tube defects only - not safe but better) and phenytoin (cleft lips, congenital heart defects and narrow therapeutic window so needs rigorous monitoring).
Prescribe the lowest effective dose and spread it throughout the day. Start folate suppliments ideally before conception.

Question 28

Describe the process of beginning an antiepileptic. (2)

Answer 28

Begin with lowest dose possible and build up until control is reached.

Question 29

Describe the process of changing an AED. (3)

Give two reasons for changing an AED. (2)

Answer 29

While still on the old drug, begin the new one and increase slowly to the middle of the therapeutic range. Slowly remove old drug.
Unacceptable side effects, failure of treatment.

Question 30

Describe the criteria for considering removal of AEDs in a patient. (1)

Answer 30

Seizure free for 2 years.

Question 31

Describe those who have a higher risk of seizure if their AEDs have been withdrawn, even if they meet the criteria. (4)

Answer 31

Epilepsy since childhood
Epilepsy caused by known underlying brain damage.
Abnormal EEG in the last year.
Patient on more than one drug.

Question 32

Describe the treatment for Status Epilepticus. (2)

Answer 32

IV Phenytoin or benzodiazepines.

Question 33

Describe daily considerations that need to be taken into account when diagnosed with epilepsy. (5)

Answer 33

DVLA considerations for driving
Machinery operation
Bathing self / babies supervised 
Don’t cycle on roads 
Avoid alcohol

Question 34

Describe long term considerations that need to be taken into account when diagnosed with epilepsy. (3)

Answer 34

Annual review of epilepsy (check compliance, lifestyle, and contraception)
Sudden unexpected death in pregnancy higher risk
Higher risk of mental illness.