Epilepsy

Question 1

What percentage of the population suffers from epilepsy?

Answer 1

0.5-1%.

Question 2

What percentage of the population suffers at least one seizure in their lifetime?

Answer 2

At least 2%.

Question 3

How many new epilepsy cases present each year?

Answer 3

30,000.

Question 4

What percentage of epilepsy cases are refractory to drug treatment?

Answer 4

30%.

Question 5

What percentage of epilepsy cases arent improved by surgery?

Answer 5

20-30%.

Question 6

Hoe many epilepsy related deaths are there per year?

Answer 6

1000.

Question 7

What percentage of epilepsy deaths are sudden death in epilepsy (SUDEP)?

Answer 7

50%.

Question 8

What percentage of epilepsy cases go undiagnosed or untreated in developing countries?

Answer 8

60-90%.

Question 9

What is reflex epilepsy?

Answer 9

Their seizures are triggered by TV, sunlight through leaves, strobe lighting, sunlight on water. 0.001% of sufferers have musicogenic seizures. Their triggers include eating, tooth brushing, certain smells, playing chess, writing, reading, or doing sums/puzzles.

Question 10

What percentage of epilepsy sufferers are affected by reflex epilepsy?

Answer 10

7%.

Question 11

Why do seizures happen?

Answer 11

Sub-clinical changes in patterns of network activity drive maladaptive processes in susceptible networks. At a critical point, spontaneous recurrent seizures manifest. Epileptogenesis continues through maladaptation in target networks. ‘Seizures beget seizures’ – Gaddum.

Question 12

How is behaviour affected by epilepsy?

Answer 12

Epilepsy is also associated with changes in behaviour that vary according to the part of the brain affected and severity and can include involuntary muscle contraction and a temporary loss of consciousness.

Question 13

In most cases can the cause of epilepsy be determined?

Answer 13

No.

Question 14

How is epilepsy studied?

Answer 14

To study epilepsy, we make an animal model. To do this the animal is injected with a chemoconvulsant, a brain region is stimulated, and an acute preparation is used.
Models of a system are not ever exactly perfect for the system they are trying to replicate, and this should be kept in mind.

Question 15

What antiepileptic drugs act at glutamatergic synapses?

Answer 15

Iamotrigine, phenytoin, carbamazepine, sodium valporate, gabapentin, pregbalin.

Question 16

What antiepileptic drugs block sodium channels in glutamatergic synapses?

Answer 16

Iamotrigine, phenytoin, carbamazepine, sodium valporate.

Question 17

What antiepileptic drugs block calcium channels in glutamatergic synapses?

Answer 17

Gabapentin, pregbalin.

Question 18

What antiepileptic drugs act at GABAergic synapses?

Answer 18

Vigabatrin, sodium valporate, tiagabine, benzodiazepines, barbiturates.

Question 19

How do the antiepileptic drugs vigabatrin and sodium valporate work in GABAergic synapses?

Answer 19

By blocking GABA transaminase action, preventing GABA breakdown, increasing GABA levels and GABA release.

Question 20

How does the antiepileptic drug tiagabine work in GABAergic synapses?

Answer 20

Blocks GABA reuptake, increasing GABA concentration in the synaptic cleft.

Question 21

How do benzodiazepines and barbiturates (used for epilepsy) work in GABAergic synapses?

Answer 21

Increase postsynaptic response by prolonging channel opening time.

Question 22

The choice of anti-epileptic drug is based upon which factors?

Answer 22

• Seizure type.
• Epilepsy syndrome – special syndromes (West Syndrome, Dravet).
• Pharmacokinetic profile with regards to the patient.
• Interactions/other medical conditions.
• Efficacy.
• Expected adverse effects.
• Cost.

Question 23

Define partial onset seizures.

Answer 23

This is where the electrical disturbance is limited to a specific area of one cerebral hemisphere.

Question 24

What drugs are used to treat partial onset seizures?

Answer 24

• Carbamazepine.
• Phenytoin.
• Felbamate.
• Primidone.
• Gabapentin.
• Tiagabine.
• Lamotrigine.
• Topiramate.
• Levetiracetam.
• Valproate.
• Oxcarbazepine.
• Zonisamide.
• Phenobarbital.

Question 25

Define absence seizures.

Answer 25

Absence seizures are a type of generalised onset seizure, meaning both sides of your brain are affected from the start. In the past absence seizures used to be called petit-mal seizures. The 2 most common types of absence seizure are typical and atypical.

Question 26

What antiepileptic drugs are used to treat absence seizures?

Answer 26

* Ethosuximide. * Lamotrigine. * Levetiracetam. * Topiramate. * Valproate. * Zonisamide.

Question 27

Define myoclonic seizures.

Answer 27

Myoclonic seizures are brief shock-like jerks of a muscle or group of muscles. They occur in a variety of epilepsy syndromes that have different characteristics. During a myoclonic seizure, the person is usually awake and able to think clearly.

Question 28

What entiepileptic drugs are used to treat myoclonic seizures?

Answer 28

* Clonazapam. * Lamotrigine. * Levetiracetam. * Topiramate. * Valproate. * Zonisamide.

Question 29

Define tonic-clonic seizures.

Answer 29

During a generalized tonic-clonic (formerly grand mal) seizure, electric discharges instantaneously involve the entire brain. The person loses consciousness right from the beginning of the seizure.

Question 30

What antiepileptic drugs are used to treat tonic-clonic seizures?

Answer 30

* Carbamazepine. * Phenytoin. * Felbamate. * Topiramate. * Lamotrigine. * Valproate. * Levetiracetam. * Zonisamide. * Oxcarbazepine.

Question 31

What three categories can adverse effects to anti-epileptic drugs be broken into?

Answer 31

* Acute dose-related – reversible, * Idiosyncratic – uncommon, potentially serious or life threatening. * Chronic – reversibility and seriousness vary.

Question 32

What acute, dose related adverse effects may be seen with antiepileptic drugs?

Answer 32

``` • Neurologic/Psychiatric – most common. o Sedation, fatigue. o Unsteadiness, lack of coordination, dizziness. o Tremor. o Paraesthesia – tingling. o Diplopia, blurred vision (esp. carbamazepine). o Mental/motor slowing or impairment o Mood or behavioural changes. o Changes in libido or sexual function. • Gastrointestinal (nausea, heartburn). • Mild to moderate laboratory changes. o Hyponatremia (may be asymptomatic). o Increases in ALT or AST. o Leukopenia. o Thrombocytopenia. • Weight gain/appetite changes. ```

Question 33

What idiosyncratic adverse effects may be seen with antiepileptic drugs?

Answer 33

• Rash, Exfoliation. • Signs of potential Stevens-Johnson syndrome. o Hepatic Damage. o Early symptoms: abdominal pain, vomiting, jaundice. o Laboratory monitoring probably not helpful in early detection. o Patient education. o Fever and mucus membrane involvement. • Hematologic damage - (marrow aplasia, agranulocytosis - CBZ). o Early symptoms: abnormal bleeding, acute onset of fever, symptoms of anemia. o Laboratory monitoring probably not helpful in early detection. o Patient education.

Question 34

What long term adverse effects may be seen with antiepileptic drugs?

Answer 34

• Neurologic: o Neuropathy. o Cerebellar syndrome (PHT) – irreversible – phenytoin. • Endocrine/Metabolic Effects. o Vitamin K/D – bleeding (HDN), osteomalacia, osteoporosis. o Folate – Anemia, teratogenesis. o Altered connective tissue metabolism or growth.  Facial coarsening.  Hirsutism – hair growth.  Gingival hyperplasia.

Question 35

Foetal abnormalities in mothers with epilepsy can be down to what factors?

Answer 35

* Drug effects. * Consequences of the mothers underlying diseases. * Consequences of maternal seizures during pregnancy.

Question 36

How should epileptic women who want to become pregnant be educated?

Answer 36

The patient should be properly educated on the risks they are presented with. All women of child-bearing potential should receive education and carefully considered management before and during pregnancy to optimize the chances of a good outcome for both mother and child.

Question 37

What should epilepsy education for pregnant mothers include?

Answer 37

* Most women with epilepsy have normal children. * Risk of fetal malformations is increased. * AED teratogenicity is related to exposure in the first trimester of pregnancy. * Prenatal diagnosis of fetal malformations is possible. * Seizures may be deleterious to the fetus. * Compliance with AED treatment is important.

Question 38

Before pregnancy in an epileptic mother, what should one do?

Answer 38

* Attempt anti-epileptic drug monotherapy with the lowest effective dose. * Offer folate supplementation (5mg/day orally) – to prevent spina bifida etc.

Question 39

During/after pregnancy in an epileptic mother, what should one do?

Answer 39

* Monitor AED dose requirements to maximize seizure control. * Continue folate supplementation. * Consider prenatal diagnosis of fetal malformations. * Vit K (1mg at delivery).