Epilepsy Flashcards
What is the definition of Epilepsy?
- A chronic neurological disorder, characterised by recurrent seizures
What is the definition of a seizure?
- A seizure refers to a transient neurological change due to a synchronous, hyperexcited neuronal activity in the brain
What is a provoked seizure?
- These strokes occur at the time of acute illness
- They include acute stroke, head trauma and hypoglycaemia)
What are the types of seizure that occur in Epilepsy?
- recurrent, unprovoked seizures
What are the causes of Epilepsy?
- Genetic
- Structural (visible neurological abnormalities- cerebrovascular disease and congenital malformation)
- Metabolic
- Immune
- Infectious (chronic infection predisposing to seizure - HIV)
- Unknown
What is the Pathophysiology of Seizures?
- Seizures develop due to an imbalance between inhibitory and excitatory signals in the brain
- A seizure may be due to high frequency bursts of excitatory action potentials, this leads to synchronous, hyperexcitable activity
What are the two types of inhibitory and exhibitory signals?
- Gabanergic
- Glutamingergic
What are the Gabanergic signals?
- inhibitory GABA receptors
- These are ligand gated ion channels that allow the flow of the chloride ions
- GABA is the main inhibitory neurotransmitter that binds to these receptors
What are the Glutaminergic signals?
- Excitatory, glutamate receptors
What are the Risk Factors for Epilepsy?
- Cerebrovascular disease
- Head trauma
- Cerebral infections
- Family History
- Premature birth
- Congenital malformations of the brain
- Genetic conditions associated with epilepsy
How are Seizures classified?
- Seizure type
- Epilepsy type
- Epilepsy syndrome
What 3 classifications can the “seizure type” be split into?
- Area of Onset
- Awareness
- Clinical Features
What are the Areas of Onset for Seizure type?
- Focal (one hemisphere of the brain)
- Generalised (affecting both hemispheres of the brain and associated neuronal networks)
- Focal to bilateral tonic-clonic (focal seizure spreads to affect wider network of Neurons involving both hemispheres)
What is included in Awareness for seizure type?
- Awareness ( fully aware of themselves and their environment throughout the seizure)
- Impaired Awareness (any impairment of awareness during course of the seizure
What is included in Clinical Features of seizure type?
- Motor ( Tonic (generalised muscle stiffening), Clonic (rhythmic muscle jerking), Myoclonic (brief, shock like, involuntary jerks), Atonic (loss of motor tone), spasms ( sudden Flexion/ extension movements)
- Non- Motor ( focal onset associated with sensory, emotional, automatic or behavioural change / generalised onset with symptoms typical of an absence seizure)
What are the epilepsy types?
- Focal Epilepsy
- Generalised Epilepsy
- Generalised and focal Epilepsy
- Unknown Epilepsy
What is included in Epilepsy Syndrome?
- Epilepsy syndrome is characterised by the recurrent propensity to a specific seizure type or series of seizure types
- Determining an epilepsy syndrome is important to guide medical therapy with anti-epileptic drugs
What are examples of classic epilepsy syndrome?
- West Syndrome
-Lennox Gastaut Syndrome - Juvenile Myoclonic Epilepsy
What is important to know about the epilepsy syndromes ?
- Typical age of onset
- Specific seizure types
- Specific EEG features
- Additional clinical or radiological features
What are the clinical features of seizures?
- Epilepsy is characterised clinically by seizures
What are the 4 stages of a Seizure?
- Prodromal
- Early- Ictal
- Ictal
- Post- Ictal
What is the Prodromal period of a Seizure?
- This is a feeling/ sensation of confusion, irritability or mood disturbances that predisposes a seizure
What is the Early- Ictal period?
- This phase is characterised by an aura, this is the earliest sign of seizure activity
- It refers to subjective symptoms experienced by the patient including sensory, cognitive, emotional or behavioural changes
- an aura is suggestive of a focal epilepsy which may progress to affect a wider area or develop into a focal to bilateral tonic-clonic seizure
What is the Ictal period?
- This is a highly variable stage depending on seizure type
- A seizure is typically tonic-clonic seizure, this is characterised by stiffening and subsequent rhythmic jerking of the limbs
- It is typically associated with urinary incontinence and tongue biting and typically lasts 1-2 minutes
What is Status Epilepticus?
- This is when a single seizure lasts greater than 30 minutes
- Or when two seizures occur without regaining consciousness after the first
- It can be broadly split into convulsive and non-convulsive
What is the Post-Ictal period?
- This is the recovery period when the seizure has abated
- There may be an extended recovery period which is dependant on seizure types
- During this period, there may be altered consciousness, confusion, memory loss, drowsiness or genera, malaise
How do you make a diagnosis of epilepsy?
- Criteria 1: more than or equal to 2 unprovoked seizures occurring more than 24 hours apart
- Criteria 2: 1 unprovoked seizure with a probability of further seizures felt to be at a similar recurrence risk to patients with more than or equal to 2 unprovoked seizures over the next 10 years
- Criteria 3: A diagnosed epilepsy syndrome
What are the differential diagnoses for Epilepsy?
- Syncope and anoxic seizures (transient loss of consciousness from impaired cerebral blood flow)
- Behavioural, psychological and psychiatric ( non-epileptic seizures = pseudo seizures)
- Sleep-related conditions
- Paroxysmal movement disorders
- Migraine associated disorders
What Investigations are indicated for Epilepsy?
- Neuroimaging and an EEG
- ECG
- Bloods: FBC,U&E, LFT, Glucose and Bone Profile
What is an EEG?
- This is a non-invasive method of assessing and recording the electrical activity of the brain
- Epilepsy has a certain waveform that is present
What are the 3 main uses for an EEG?
- Support a diagnosis of Epilepsy
- Assess risk of seizure recurrence
- Determine seizure type of epilepsy syndrome
What is Neuroimaging?
- This is an MRI and a CT can be used if MRI is not available
- This is able to look for structural abnormalities
What are the main stages of treatment for Epilepsy?
- Education and Safety
- Treating Acute seizures
- First Fit Clinic
- Long term treatment with AED
What is included in the management regarding Education and Safety?
- Driving
- Water safety - using buddy system, showers instead of baths
- Fire Safety
- Environmental safety
- Care with heights, high risk recreational activities, contraception and certain medications
What is a first fit clinic?
- After an initial presentation and management of a suspected epileptic seizure the patient should go to a first fit clinic
- This is a formal assessment (history and examination), relevant investigations (MRI, EEG)
- As a general rule, following a single seizure patients are not routinely started on AEDs unless there is felt to be considerable risk for another seizure
What are the options for Anti-Epileptic Drugs?
- Sodium Valproate
- Carbamazepine
- Lamotrigine
- Levetiracetam
- Phenytoin
What is the important information to note about Sodium Valproate?
- Teratogenic
- Side Effects: drug-induced liver injury, pancreatitis and increased suicide risk
What is the important information to know about Carbamazepine?
- Sodium channel antagonist
- Increased teratogenic risk
- Side effects: Agranulocytosis, SIADH
What important information should you know for Lamotrigine?
- Sodium channel antagonist
- Increased teratogenic risk
- Side effects: severe skin reactions
What important information is needed for Levetiracetam?
- Unclear mechanism
- Side Effects: CNS disturbance, neuropsychiatric disturbance
What important information is needed for Phenytoin?
- Sodium channel antagonist
- Teratogenic
- Side effects: Arrhythmia with parenteral use, Gum hypertrophy and cerebella atrophy
What information should you know about anti-epileptic drugs and pregnancy?
- Sodium Valproate is highly teratogenic and therefore should not be given to women and girls of childbearing potential
- This includes girls who are likely to need treatment into their child bearing years
What is the general rule for medication for patients with Epilepsy?
- Monotherapy at the lowest possible dose to control seizures
What is the management for Focal Seizures?
- 1st - Lamotrigine (if childbearing potential), Carbamazepine (no childbearing potential)
- 2nd - Levetiracetam, Oxcarbazepine or Sodium Valproate
What is the management for Generalised Tonic-Clonic Seizures?
- 1st - Sodium Valproate/ Lamotrigine
- 2nd - Clobazam, Lamotrigine, Levetiracetam or Topiramate
What is the management for Absence Seizures?
- 1st - Sodium Valproate or Ethosuximide
- 2nd - Lamotrigine
What is the management for Myoclonic Seizures?
- 1st - Sodium Valproate
- 2nd - Levetiracetam or Topiramate
What is the management for Juvenile Myoclonic Epilepsy?
- 1st - Sodium Valproate
- 2nd - Lamotrigine, Levetiracetam or Topiramate
What medications can impair the effectiveness of hormonal contraceptives?
- Oxycarbazepine and Topiramate
What are the two major complications of Epilepsy?
- status epilepticus
- SUDEP ( sudden unexplained death in epilepsy) - this is the most common cause of death in young adults with epilepsy
- SUDEP - has been linked to uncontrolled epilepsy and nocturnal seizures
- Seizure control is Pivotal to reduce risk
What is the general advice for epilepsy and driving?
- First Seizure (group 1)- Impaired consciousness: do not drive for six months, reapply
- Epileptic seizure (group 1) - Impaired consciousness: do not drive for one year, reapply
- Seizures (group 1) - no loss of consciousness (seek DVLA advice)
- First Seizure (group 2) - do not drive for 5 years, seek DVLA advice
- More than or equal to one seizure (group 2) - do not drive for 10 years, seek DVLA advice
What are the features of Temporal Lobe Seizures?
- May occur with/ without impairment of consciousness or awareness
- a rising in epigastric sensation
- a psychic/ experiential phenomena = deja vu
- hallucinations (auditory/ gustatory/ olfactory)
- Seizure last one minutes
- Automatisms (lip smacking/grabbing/plucking)
What are the features of Frontal Lobe Seizures?
- Head/leg movements
- Posturing
- Post-ictal weakness
- Jacksonian march
What are the features of Parietal Lobe Seizures?
- Paraesthesia
What are the features of Occipital Lobe Seizures?
- Floaters/ Flashes
