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The Patient Y3 Semester 2 > Epilepsy > Flashcards

Epilepsy Flashcards

1
Q

What is a seizure?

A

A SEIZURE is an episode of neurological dysfunction of abnormal firing of neurones manifesting as changes in motor control/sensory perception/behaviour/autonomic function.

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2
Q

What is epilepsy?

A

EPILEPSY is the condition of recurrent, spontaneous seizures arising from abnormal, synchronous and sustained electrical activity in the brain.

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3
Q

Aetiology of epilepsy?

A
  • Idiopathic epilepsy – genetic cause
  • Symptomatic epilepsy (e.g. Head injury/stroke)
  • Up to 50% have no apparent cause
  • Up to 40% may have a genetic component
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4
Q

Diagnosis of epilepsy?

A

First step of diagnosis is to establish if paroxysmal event was actually a seizure or something else.

Good history taking and witnesses are useful
Epilepsy is spontaneous and recurrent.

Diagnosis should be made by a specialist (NICE, 2012)
There is no single diagnostic tool, good history taking is key

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5
Q

Clinical diagnosis decision is based upon:

A
  • Description of attack – witness accounts/video footage
  • Family history – Genetic cause?
  • Blood tests – low Na
  • ECG – cardiac cause? Syncope?
  • Medication history
  • -> Legal and illicit drugs can cause seizures
  • -> Overdose of some drugs can lead to seizures
  • -> Many commonly prescribed drugs can lower seizure threshold
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6
Q

Neuroimaging and EEGs for epilepsy:

A
  • MRI is better than CT
  • Visualisation of structural abnormalities
  • Important in those <2 years or adults who develop seizures, and those refractory to AEDs
  • NICE recommend should be performed within 4 weeks
  • EEGs should never be used in isolation
  • Main role is to classify epilepsy
  • 10% of epileptic patients never show changes
  • 2-4% of healthy people can have abnormal EEGs.
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7
Q

Classification of Seizures:

A
  • May have more than one type of epilepsy
  • Depend on the location and focus on the pathways involved
  • Failure to classify can lead to inappropriate treatment and treatment failure.

Two Main Types:

1) Partial seizures
- Simple partial seizures – maintain consciousness
- Complex partial seizures – don’t maintain consciousness, aura
- With Secondary Generalisation

2) Generalised seizures
- Tonic (muscle tense)/Clonic (limb shaking, biting tongue)
- Absence – short
- Myoclonic – limb jerking
- Atonic – drop attacks

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8
Q

Seizure triggers:

A
  • Fatigue
  • Lack of sleep
  • Stress
  • Alcohol
  • Flashing lights (photosensitive epilepsy)
  • Excitement
  • Menstruation
  • Missing meals
  • Some medications
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9
Q

Nice guidelines on PHARMACOLOGICAL MANAGEMENT in epilepsy:

A
  • Always initiated by a specialist, after a diagnosis
  • Monotherapy should be used where possible
    Start low, go slow
  • Adjunctive (add on) treatment should only be considered when monotherapy has failed
  • AEDs are not usually started after a first seizure (except if quite clear abnormality
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10
Q

Aim of Therapy in epilepsy?

A
  • Single Agent
  • Lowest Dose
  • Minimum Side Effects
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11
Q

Treatment should be tailored to the individual taking into account:

A

Patient factors

  • Epilepsy syndrome
  • Seizure type
  • Co-morbidity
  • Lifestyle
  • Gender
  • Age
  • Preferences of individual/family/carers

Drug Factors

  • Side effect profile
  • Dose
  • Treatment schedule
  • Formulation
  • Interactions
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12
Q

Generalised Tonic/Clonic 1st line treatment:

A

Carbamazepine, Lamotrigine, Na Valproate, Oxcarbazepine

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13
Q

Tonic or Atonic 1st line treatment:

A

Na Valproate

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14
Q

Absense siezure 1st line treatment:

A

Ethosuximide, Lamotrigine, Na Valproate

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15
Q

Myoclonic seizure 1st line treatment:

A

Levetiracetam, Na Valproate, Topiramate

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16
Q

Focal seizure type 1st line treatment:

A

Carbamazepine, Lamotrigine, Levetiracetam, Oxcarbazepine, Na Valproate

17
Q

Describe sodium valproate:

A

1st line therapy in multiple seizure types

Initially 600mg/day in 1 - 2 divided doses increased gradually every 3 days

MHRA: Should be avoided in pregnant women and women of childbearing potential due to risk of neurodevelopmental defects.
Dosage forms = EC tablets, MR tablets, liquid, granules, IV
IV dose = Oral doses
Monitor for signs of liver, blood, pancreatic disorders

Side Effects – nausea, gastric irritation, diarrhoea, weight gain, hair loss

18
Q

Describe carbamazepine:

A
  • 1st line treatment for focal seizures
  • Initially 100-200mg 1-2times daily increased slowly every 2 weeks.
  • Monitor for blood, liver or skin disorders
  • Available via PO and PR routes: 125mg suppository is equivalent to 100mg orally
  • Metabolism at CYP3A4 – potent inducer (interactions)
  • Side effects – Headache, N+V, drowsiness, dizziness, rash, ataxia, hyponatraemia
  • -> Dose related, can be dose limiting
  • -> Can be reduced by using MR tabs
19
Q

Describe lamotrigine:

A
  • Used for focal and generalised seizures
  • Initially 25mg/day and slowly titrated every two weeks
  • Serious skin reactions
  • -> Increase dose slowly
  • -> More common when also on valproate or in first 8 weeks of treatment
  • Lamotrigine considered one of safest AEDs in pregnancy
  • Oral route only
  • Side effects – nausea, vomiting, diarrhoea, dry mouth, skin reactions
20
Q

Describe Levetiracetam:

A
  • Used for partial seizures and adjunctive therapy for myoclonic seizures and tonic-clonic seizures
  • 250mg/day, increased every 1-2 weeks to max 1.5g BD
    Little metabolism, not affecting CYP450
    –> Therefore few interactions
  • Good oral bioavailability, therefore no dose alteration between oral and IV
  • Side effects: Nasopharyngitis, somnolence, fatigue, dizziness, headache
  • -> Low mood, irritability, depression are common reasons for discontinuation
21
Q

Describe phenytoin:

A
  • Not recommended by NICE for first line
  • Role in refractory seizures and status epilepticus
  • Initially 3-4mg/kg/day (usual dose 200-500mg/day)
    Dose adjusted according to levels and effect
  • Narrow therapeutic index with saturable kinetics
  • Half life 4-72 hours (depends on dose). Steady state reached after 7-10days
  • Extensive hepatic metabolism
  • Strong inducer of CYP450 - interactions
  • Highly protein bound – albumin
  • Interactions with enteral feeding
  • Capsules and IV = Phenytoin sodium
  • Liquid, chewable tablets = phenytoin base
  • -> 100mg phenytoin sodium = 92mg phenytoin
  • -> Need to be careful when switching formulations

Side effects – N+V, constipation, drowsiness, parasthesia, gingival hyperplasia, acne, hirsuitism, coarsening of facial features.
Signs of overdose - Nystagmus, ataxia, diplopia, slurred speech, confusion, hyperglycaemia

  • Desirable plasma-phenytoin concentration = 10-20mg/litre
22
Q

Antiepileptics are divided into three categories according to the importance of maintaining a consistent supply of a particular manufacturers product/brand:

A

Category 1: Includes phenytoin, carbamazepine, phenobarbital,
Specific measures are necessary to ensure consistent supply of a particular product

Category 2: Includes sodium valproate, lamotrigine, oxcarbazepine
The need for continued supply based on clinical judgement

Category 3: Includes levetiracetam, lacosamide, gabapentin
No specific measures required

23
Q

Women and epilepsy:

A

Antiepileptics interact with hormonal medications

  • Can reduce effectiveness as enzyme inducers. E.g. Carbamazepine, phenytoin
  • Oral contraceptives and EHC can reduce effectiveness of lamotrigine.
  • May need to increase dose of lamotrigine
  • Some AEDs are teratogens/can cause birth/developmental defects
  • These drugs are to be avoided in women of childbearing potential and pregnant women
  • Pharmacokinetics can be altered in pregnancy
  • All women on AEDs should be offered folic acid 5mg OD before any possibility of pregnancy
  • Some women have increased seizure frequency around menstruation
  • Side effects of some AEDs may be undesirable
24
Q

Epilepsy and Older People: Pharmacokinetic and pharmacodynamic issues

A

Polypharmacy
Co-morbidity

Consider using lower doses of AEDs

If on carbamazepine, this should be modified release

25
Q

What is Status Epilepticus?

A

Medical emergency associated with significant morbidity and mortality
Efficient and effective treatment is key
Aim of treatment is seizure termination

Generalised Convulsive Status Epilepticus is defined as a tonic clonic seizure which lasts longer than 30 minutes or repeated tonic clonic seizures within 30 minutes with little or no recovery in between

26
Q

Status Epilepticus - Treatment

A
  • IV Lorazepam 0.1mg/kg (usually 4mg), repeated once after 10-20 minutes if seizure continues
  • -> Give usual AEDs if already on treatment
  • -> Alternatives to lorazepam are IV diazepam or buccal midazolam
  • Phenytoin IV 20mg/kg over 20 minutes (or phenobarbital if already on phenytoin)
  • General anaesthesia if above does not work
27
Q

Treatment Failure and Resistance:

A 
If treatment fails despite maximal doses
- Check compliance
- Has brand/formulation changed?
See MHRA guidance
- Check diagnosis (NICE)
Wrong treatment for seizure type?
- ?brain tumour
- Alcohol/drug misuse

None of the above?

  • Change to second line therapy
  • Initiate second drug, increase to therapeutic dose then wean first drug
  • Avoid abrupt withdrawal of AEDs – risk of rebound seizures
28
Q

Combination Therapy:

A

Combination therapy should only be initiated by a specialist after treatment failure with monotherapy
Many newer drugs have demonstrated efficacy as ‘add-on’ therapy

If combination therapy doesn’t work….
Revert to regimen that provided the best balance of tolerability and efficacy
May be monotherapy or combination therapy

29
Q

Problems with combination therapy:

A
  • Drug interactions
  • -> Potent inducers/inhibitors of hepatic enzymes
  • -> Drug-Drug interactions between AEDs
  • Increased toxicity
  • -> Interactions can increase plasma concentration
  • -> Additive side effects
  • Identifying ADRs
    Can be difficult to differentiate
  • Non—compliance
    Increased pill burden
    Unpleasant side effects
30
Q

Treatment withdrawal:

A
  • Joint decision taken by patient and family/carers
  • Under the guidance of a specialist

Must be seizure free for 2 years before considering withdrawal

  • Withdrawal must be carried out slowly over months
  • One drug at a time if on combination therapy

A failsafe plan must be in place in case seizures recur.
- Last dose reduction is reversed and medical advice sought

31
Q

Information for patients:

A
  • All aspects of care discussed prior to treatment
  • Importance of compliance explained – even when seizure free
  • Dosing schedule and dose titration

Signs and symptoms of adverse effects

  • Blood disorders
  • Liver dysfunction
  • Skin disorders
  • Brands and formulations
  • MHRA/NICE
  • OTC and other medications
32
Q

Social Aspects of Diagnosis:

A
  • Employment
    Cannot be refused employment under Equality Act 2010 but employers must consider health and safety

Driving
- If you have a seizure you must stop driving and tell the DVLA
- Group 1 license: cars and motorbikes, after one year seizure free (on/off AEDs)
Can learn to drive at 17 if one year seizure free
Consider side effects of AEDs such as drowsiness

  • Alcohol
    –> Interactions with AEDs
    May trigger seizures

The Patient Y3 Semester 2 (21 decks)

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