epilepsy Flashcards

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1
Q

What is epilepsy?

A

Epilepsy is a chronic noncommunicable disease of the brain characterised by recurrent epileptic seizures

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2
Q

What are the epileptic seizures like?

A

pileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical activity in the brain

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3
Q

What causes epilepsy?

A

The cause of epilepsy remains unknown in approximately 50% of all cases globally. Generally speaking, the causes can be divided as follows:

  1. Structural
  2. Genetic
  3. Infectious
  4. Metabolic
  5. Immune
  6. Unknown
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4
Q

What are structural causes of epilepsy?

A

Brain damage from prenatal or perinatal causes

Congenital abnormalities or genetic conditions with associated brain malformations

Severe head injury

Stroke

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5
Q

What percentage of epilepsy is preventable?

A

25%

reducing head injuries, preventing infection and using drugs to lower severe fevers in children

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6
Q

How would you categorise seizures in epilepsy?

A

Seizure types are divided into two main categories:

  1. Partial (focal) seizures
  2. Generalised seizures

Partial seizures can spread and cause secondary generalisation

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7
Q

What are partial seizures in epilepsy?

A

Caused by electrical discharge restricted to a limited part of the cortex of one cerebral hemisphere.

Partial seizures are further sub-divided according to whether or not there is loss of awareness

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8
Q

What are simple partial seizures in epilepsy?

A

A partial seizure WITHOUT loss of awareness

Originates in motor cortex

Typically results in jerking which spreads to one half of the body

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9
Q

What are complex partial seizures in epilepsy?

A

A partial seizure WITH loss of awareness

Usually originates in temporal lobe, but can arise in frontal lobe

Can lead to deja vu, hallucinations or fear

There follows a period of complete or partial loss of awareness of surroundings, lasting for 1–2 minutes on average. This is accompanied with involuntary motor movement

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10
Q

What are generalised seizures in epilepsy?

A

Simultaneous involvement of both hemispheres, always associated with loss of consciousness or awareness

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11
Q

What is a typical absence seizure in epilepsy?

A

Generalised seizure with conscious loss

There is loss of awareness and a vacant expression for <10 seconds before returning abruptly to normal and continuing as though nothing had happened. No motor symptoms

Due to primary generalised epilepsy, NEVER due to acquired lesions

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12
Q

What is a generalised tonic-clonic seizure in epilepsy?

A

An initial tonic stiffening is followed by the clonic phase with synchronous jerking of the limbs, reducing in frequency over about 2 minutes until the convulsion stops

This is often followed by a period of flaccid unresponsiveness and confusion and drowsiness asting 15 minutes to an hour or longer. Headache is common after a GTCS.

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13
Q

What are myoclonic, tonic and atonic seizures in epilepsy?

A

Myoclonic seizures or ‘jerks’ take the form of momentary brief contractions of a muscle or muscle groups, e.g. causing a sudden involuntary twitch of a finger or hand.

Tonic seizures consist of stiffening of the body, not followed by jerking.

Atonic seizure. A sudden collapse with loss of muscle tone and consciousness.

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14
Q

How would you diagnose epilepsy?

A
  1. Extensive patient history, including drug and alcohol use
  2. Serum calcium
  3. ECG
  4. EEG
  5. Brain MRI
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15
Q

What would you see on an EEG in epilepsy?

A
  • Focal cortical spikes or generalised spike and wave activity are abnormal
  • Epileptic activity is continuous
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16
Q

What is the recurrence rate of epileptic seizures after a first episode?

A

Some 70–80% of people will have a second seizure, the risk

being highest in the first 6 months after the initial seizure

17
Q

How would you manage epilepsy?

A

A prolonged seizure may be treated with rectal diazepam, lorazepam or buccal midazolam

  1. Anitepileptic Drugs (AEDs)
  2. Surgery
18
Q

What is status epileptics and how would you treat it?

A

Status epilepticus means a medical emergency of a seizure lasting for over 30 minutes.

Status epilepticus has a mortality of 10–15%. The longer the duration of status, the greater the risk of permanent cerebral damage. Rhabdomyolysis may lead to acute kidney injury in convulsive status epilepticus.

19
Q

What do you know about antiepileptic drugs and their use in epilepsy?

A

First line: sodium valproate, levetiracetam, lamotrigine

Aim for mono therapy - 70% of patients will have good
seizure control with a single AED.

There are interactions between AEDs (and with other medications), e.g. between sodium valproate and lamotrigine. New generation AEDs have fewer interactions.

20
Q

How does sodium valproate work?

A

Salproate sodium is converted into its active form, valproate ion, in blood. Although the mechanism of action remains to be elucidated, valproate sodium increases concentrations of gamma-aminobutyric acid (GABA) in the brain, probably due to inhibition of the enzymes responsible for the catabolism of GABA.

21
Q

Would you ever consider stopping antiepileptic drugs in an epilepsy patient?

A

Withdrawal of AEDs should be considered after a seizure-free period of at least 2–3 years. There is a 50% seizure recurrence rate after withdrawal so careful discussion and explanation are essential.

22
Q

When would you consider surgery in epilepsy?

A

Uncontrolled seizures caused by hippocampal sclerosis

Temporal lobectomy will result in seizure freedom in 50–70%

23
Q

Would you continue antiepileptic drugs during pregnancy?

A

The overall risk of birth defects in babies of
mothers who take one AED is around 7%, as compared with
3% in women without epilepsy

The risk to the fetus of uncontrolled seizures
is greater than the risks of continuing AED treatment

Breastfeeding is okay

24
Q

How do antiepileptic drugs influence contraception?

A

AEDs inducing hepatic enzymes (e.g. car-
bamazepine, phenytoin and phenobarbital) reduce efficacy
of oral contraceptives

A combined contraceptive pill containing a higher dose of oestrogen or the progesterone-only
pill provides greater contraceptive security

25
Q

What are the main three types of epilepsy?

A
  1. Primary generalised
  2. Symptomatic and localisation-related epilepsy (LRE)
  3. Hippocampal sclerosis
26
Q

What is the prognosis for Childhood absence epilepsy?

A

Spontaneous remission by age 18 is usual