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S4 Pharma CPT > Epilepsy > Flashcards

Epilepsy Flashcards

1
Q

Define a seizure

A

Transient occurrence of signs or symptoms due to abnormal electrical activity in the brain, leading to a disturbance of consciousness, behaviour, emotion, motor function or sensation

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2
Q

Most important excitatory neurotransmitter Via which receptor? How does it work?

A

Glutamate via NMDA R

Cation channel (Na/ Ca in, K out)
Depolarises membrane
More likely to fire AP

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3
Q

Most important inhibitory neurotransmitter Via which receptor? How does this work?

A

GABA via GABAa R

CL- channel
Hyperpolarises membrane
Less likely to fire AP

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4
Q

Pathology of seizures

A

Normal brain - inhibitory and excitatory sides are in balance

A seizure: manifestation of abnormal XS excitation & synchronisation of a group of neurones within brain

Caused by: loss of inhibitory (GABA mediated) signals OR too strong excitatory (NMDA/ glutamate) signals

  • genetic variation (brain chemistry/ R structure)
  • exogenous activation receptors (drugs)
  • acquired changes brain chemistry (drug withdrawal, metabolic changes (decreased Na/ glucose)
  • damage any of these networks (strokes/ tumours)
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5
Q

Symptoms and signs of seizure

A
  1. Often an aura prior e.g. headache/ funny sensations/ de ja vu
  2. Generalised seizures - loss of consciousness often, changes in muscle tone, tongue biting
    May also:
  3. For tonic-clonic seizures - initial hypertonic phase, followed rapid clonus (shaking/ jerking)
    OR
  4. For atonic seizures - lose all muscle tone (don’t fit)
  5. Post- ictal period minutes- hours (reduced consciousness)
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6
Q

Define epilepsy

A

Tendency toward recurrent seizures unprovoked by a systemic or neurological insult

Criteria, one of:

  • 2+ unprovoked (or reflex) seizures occurring more than 24hrs apart
  • 1 unprovoked/ reflex seizure & a probability of further seizures similar to general recurrence risk after 2 unprovoked (_>60% over next 10yrs)
  • diagnosis of an epilepsy syndrome
  • made by a specialist in an epilepsy or first fit clinic
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7
Q

What is a reflex seizure? List some types

A 
Seizure brought on by a particular stimulus: 
Photogenic 
Concentrating 
Eating 
Hot water immersion 
Reading 
Orgasm
Movement
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8
Q

Classification of seizure types

A

Focal onset - one side of brain affected (can eventually spread to both sides) - aware or impaired awareness - motor or nonmotor onset

Generalised onset (bilateral spread rapidly) - impaired awareness or LOC - motor (tonic-clonic, other motor) or nonmotor (absence - odd behaviour/ vacant e.g. typical/ atypical/ myoclonus/ eyelid myoclonic)

Unknown onset - motor (tonic-clonic/ other motor) or nonmotor - unclassified

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9
Q

What is a generalised seizure?

A

Originate at some point within -> rapidly engage bilaterally

CN include cortical & subcortical structures but not necessarily the entire cortex

Old term= grand mal
Old term for absence seizure = petit mal

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10
Q

What is a focal seizure?

A

Originates within networks limited to one hemisphere, may be discretely localised or more widely distributed (can eventually become bilateral)

Old term = partial seizure

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11
Q

What is a provoked seizure?

A

Seizure as a result of another medical condition, e.g.:

  • drug use/ withdrawal
  • alcohol withdrawal
  • head trauma & IC bleeding
  • metabolic disturbances (hyponatraemia/ hypoglycaemic)
  • CNS infections
  • febrile seizures infants
  • uncontrolled hypertension

Unlikely need ongoing AED treatment if cause treated

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12
Q

Differentials for seizures

A
  • syncopal-episodes e.g. vasovagal syncope
  • cardiac issues e.g. reflex anoxic seizures, arrhythmias
  • movement disorders e.g. parkinsons, huntingtons
  • TIAs
  • migraines
  • non-epileptic attack disorders (old term= pseudo- seizures)
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13
Q

Initial management of a seizure

A

A-E assessment:

  • Airway
  • breathing (O2 sats)
  • circulation (high HR, BP normally high, can go low drugs)
  • disability (consciousness level)
  • Execute recovery position

Start a timer
Get help

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14
Q

What is status epilepticus?

A

A seizure lasting _>5mins or multiple seizures without complete recovery _>5mins

Medical emergency

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15
Q

How to treat status epilepticus

A

Wait and if needed move on to next step

  1. Wait 5 minutes
  2. Benzodiazepine (full dose, give gradually)
  3. Benzodiazepines again
  4. phenytoin (or Levetriacetam) loading dose
  5. Call intensive care/ anaesthetics
  6. Thiopentone/ general anaesthesia
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16
Q

How do benzodiazepines work? Side effects, examples for use in status epilepticus

A

Class of GABAa agonists
End in -apam

Increased CL conductance = more negative resting potential, less likely to fire (work best when membrane positive e.g during seizure)

❌addictive, CVS collapse overdose, airway issues

Treatment of SE:
IV lorazepam (long acting)
Diazepam rectally
IM/ Buccal/ intranasal midazolam (mid-acting)

17
Q

Investigations for epilepsy

A

Electroencephalograph:
Record electrical activity of brain, can trigger seizure to record e.g. sleep deprivation - need capture episode or unusual activity
Many healthy ppl have abnormal EEGs

MRI:
Vascular/ structural abnormalities/ big IC bleed - only required when unsure about diagnosis of epilepsy syndrome

18
Q

List the 6 main anti-epileptic drugs (AEDs)

A 
Carbamazepine
Phenytoin 
Valproate
Lamotrigine
Levetiracetam
Benzodiazepines for seizure termination
19
Q

Which AEDs act by sodium channel blockade? How does this work?

A

Phenytoin
Carbamazepine
Valproate
Lamotrigine

Block Na channels in central neurones - slows recovery of neurones from inactive to closed state
- reduces neuronal transmission

20
Q

Side effects of carbamazepine (tegretol)

A

Suicidal thoughts
Joint pain
Bone marrow failure

21
Q

Side effects of phenytoin

A

Used mainly in status epilepticus or as an adjunct in generalised seizures

Zero order kinetics - eliminated at constant rate so care when adjusting dose

Bone marrow suppression
Hypotension
Arrhythmias (IV use)

22
Q

Side effects of Na valproate (Epilim, depakote)

A

Mix of GABAa effects & Na channel blockade & Ca channel blockade

First line for generalise d

Liver failure
Pancreatitis
Lethargy
Teratogenic

23
Q

When is lamotrigine used?

A

Primarily a Na channel blocker
May also affect Ca channels

Used often when valproate contraindicated in generalised epilepsy

24
Q

How does levetiracetam (keppra) work? When can it be used?

A

Synaptic vesicle glycoprotein binder - stops release of neurotransmitters into synapse and reduces neuronal activity

Option for focal seizures and generalised seizures

Anecdotally being used more frequently, easy dosing and well tolerated

safe in pregnancy

25
Q

General side effects of AEDs

A 
Largely common across all:
Tiredness/ drowsiness
Nausea and vomiting 
Mood changes 
Suicidal ideation 
Osteoporosis - older ppl 
Congenital malformations - greatest with valproate

Rashes including Steven Johnson syndrome (can be life threatening, muco-cutaneous breakdown)

Many can cause anaemia, thrombocytopenia or bone marrow failure

26
Q

What is required from patients on AEDs?

A

If also on warfarin need close monitoring

Ideally shouldn’t consume alcohol

Carbamazepine/ phenytoin May decrease effectiveness Of oral contraceptive pills and some antibiotics

Valproate can increase palms concentrations of other AEDs

27
Q

AEDs which are CYP enzyme inducers

A 
Phenytoin 
Carbamazepine 
Barbituates
Rifampicin
Alcohol (chronic) 
Sulphonylureas
28
Q

AEDs which are CYP enzymes inhibitors

A 
Omeprazole
Disulfram
Erythromycin
Valproate
Isoniazd
Ciprofloxacin 
Ethanol (acute) 
Sulphonamides
29
Q

When can an epileptic patient drive?

A

Temporarily lose license and need to be seizure free (with meds) for one year before reapplying

For bus/ lorry/ coach need to be seizure free for 5 years off medication for a single seizure or 10years if had multiple

Patients responsibility to inform DVLA

S4 Pharma CPT (22 decks)

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