Epilepsy Flashcards
Define what is meant by epilepsy [1]
What is needed for a dx of epilepsy? [3]
Epilepsy is an umbrella term for a condition where there is a tendency to have seizures.
- Seizures are transient episodes of abnormal electrical activity in the brain. There are many different types of seizure.
Epilepsy is a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures, and by the neurobiologic, cognitive, psychological, and social consequences of this condition. The definition of epilepsy requires the occurrence of at least one epileptic seizure. (Fisher at al 2014)]
Dx:
- 2 unprovoke seizures
- 1 and 60% likelyhood of another
NB: A single seizure is not enough
Describe the pathophysiology of epilepsy [5+]
Neuronal Excitability:
- The balance between excitatory and inhibitory neuronal activity in the brain is critical for normal function
- This equilibrium can be disrupted by various mechanisms leading to increased neuronal excitability and propensity for seizure generation
Neural Network Reorganisation:
- Following an initial insult such as head trauma, stroke or infection, there may be reorganisation within neural networks. This process of epileptogenesis, involves alterations to synaptic connectivity leading to formation of hyperexcitable neuronal circuits
- Reactive gliosis following injury or inflammation contributes significantly to epileptogenesis. Astrocytes and microglia undergo morphological and functional changes - increased extracellular potassium levels, enhanced glutamate release and reduced GABA
Inflammation:
- Following an insult, there is activation of the innate immune system leading to release of pro-inflammatory cytokines, chemokines and other inflammatory mediators
- These substances can modulate neuronal excitability, promote gliosis and induce blood-brain barrier disruption
Environmental Triggers:
- Finally, environmental factors such as sleep deprivation, stress or specific drug use can lower the seizure threshold in an individual already predisposed to seizures.
Describe the different overall types of seizures [3]
Focal Onset Seizures
Generalised Onset Seizures
Unknown Onset Seizures
Asides from recurrent, unprovoked seizures, what are the other features of a person living with epilepsy? [+]
- Depression
- Anxiety
- Short term memory loss
- Behavioural and personality changes
- Reduced fertility
- Increased risk of death (inc suicide)
- Sociobiological consequences
Describe the different types of:
Focal Onset Seizures [3]
Focal Onset Seizures
Focal Aware Seizures (previously Simple Partial Seizures):
- The individual remains conscious and can recall events during the seizure. Symptoms depend on the brain region affected.
Focal Impaired Awareness Seizures (previously Complex Partial Seizures):
- Involves alteration in consciousness. They may start as focal aware seizures and then progress.
Focal to Bilateral Tonic-Clonic Seizures:
- Begin in one hemisphere and spread to involve both, resulting in a tonic-clonic seizure.
Describe the different types of:
Generalised Onset Seizures [6]
These arise at some point within, and rapidly engage, bilaterally distributed networks.
Tonic-Clonic Seizures:
- Characterised by stiffening (tonic phase) followed by rhythmic muscle jerking (clonic phase).
Absence Seizures:
- Brief lapses in consciousness, often with staring. They can be sub-classified into typical and atypical absence seizures.
Tonic Seizures:
- Cause stiffening.
Atonic Seizures:
- Lead to loss of muscle control, often resulting in falls (‘drop attacks’).
Clonic Seizures:
- Involves repetitive jerking movements.
Myoclonic Seizures:
- Quick, sudden jerks of a muscle or group of muscles.
Describe what is meant by an unknown onset seizure [1]
When the onset of a seizure is not observed or known, it falls under this category
They can later be reclassified to either focal or generalised when more information becomes available.
Describe how epilepsy can be classified based on epilepsy syndromes [4]
An epilepsy syndrome is determined by a group of features observed together, such as the type of seizure, age of onset, EEG findings, and often prognosis. E.g:
Childhood Absence Epilepsy (CAE):
- Characterised by typical absence seizures, with onset usually between 4-10 years.
Juvenile Myoclonic Epilepsy (JME):
- Marked by myoclonic jerks, typically shortly after waking.
Dravet Syndrome:
- Severe epilepsy beginning in infancy, initially presenting as prolonged seizures with fever.
Lennox-Gastaut Syndrome:
- Characterised by multiple seizure types, cognitive dysfunction, and a specific EEG pattern.
Describe the type of seizure that would exist if it was localised to the temporal lobe [4]
An aura occurs in most patients:
* typically a rising epigastric sensation
* also psychic or experiential phenomena, such as dejà vu, jamais vu
* less commonly hallucinations (auditory/gustatory/olfactory)
Seizures typically last around one minute:
- automatisms (e.g. lip smacking/grabbing/plucking) are common
Temporal lobe focal seizures - HEAD
Hallucinations (auditory/gustatory/olfactory)
Epigastric rising sensation
Automatisms (lip smacking/grabbing/plucking)
Deja vu or jamais vu
Describe the type of seizure that would exist if it was localised to the frontal lobe [4]
Head/leg movements
posturing
Often from sleep
- patient is sleeping, wakes up, has a seizure and falls asleep. can repeat 3x4 times a night
Usually very short (10-30 secs)
post-ictal weakness
Jacksonian march (The seizure usually begins with a tingling or twitching sensation in a small area such as finger, toe, corner of the mouth. The sensation then spreads to a larger area of the body)
Can generalise to tonic clonic seizure
NB: Frontal lobe is motor lobe
Describe the type of seizure that would exist if it was localised to the parietal [1] or occipital lobes [1]
Parietal lobe (sensory):
- Paraesthesia
Occipital lobe (visual)
- Floaters/flashes
Describe the presentation of Generalised Tonic-Clonic Seizures [+]
There is loss of consciousness and tonic (muscle tensing) and clonic (muscle jerking) movements.
- Tonic before clonic (mostly); tonic stiffening of whole body, then synchronous clonic jerking
- Ictal cry
- Tongue biting
- Incontinence
- Groaning
- Irregular breathing
- After the seizure there is a prolonged post-ictal period where the person is confused, drowsy and feels irritable or low.
- Lasts 30 secs - 2 mins
- May have aura symptoms
What is the treatment for generalised tonic-clonic seizures [2]
Management of tonic-clonic seizures is with:
First line:
- sodium valproate
Second line:
- lamotrigine or carbamazepine
Focal seizures start in the [] lobes.
Describe their presentation [3]
Focal seizures start in the temporal lobes. They affect hearing, speech, memory and emotions. There are various ways that focal seizures can present:
* Hallucinations
* Memory flashbacks
* Déjà vu
* Doing strange things on autopilot
How do you treat focal seizures [2]
One way to remember the treatment is that the choice of medication is the reverse of tonic-clonic seizures:
First line:
- carbamazepine or lamotrigine
Second line:
- sodium valproate or levetiracetam
Describe the typical presentation of abscence seizures [4]
What is the management? [2]
Absence seizures:
- typically happen in children
- the patient becomes blank, stares into space and then abruptly returns to normal.
- During the episode they are unaware of their surroundings and won’t respond
- These typically only lasts 10 to 20 seconds / No longer than 5 seconds (lecture)
- Most patients (more than 90%) stop having absence seizures as they get older.
Management is:
- First line: sodium valproate or ethosuximide
What is one way you can trigger an absence seizure? [1]
- Used diagnostically
Can be triggered by hyperventilation
abscence seizures are associated with which findings on EEG? [1]
3hz spikes on EEG
Describe in detail the presentation of atonic seizures.
What is their management? [2]
Atonic seizures are also known as drop attacks.
- They are characterised by brief lapses in muscle tone.
- These don’t usually last more than 3 minutes
- They typically begin in childhood.
Management is:
First line:
- sodium valproate
Second line:
- lamotrigine
Atonic seizures - may be indicative of [] syndrome.
They may be indicative of Lennox-Gastaut syndrome.
Describe the presentation of myoclonic seizures [5]
They normally occur in children with which form of epilepsy? [1]
Myoclonic seizures present as sudden brief muscle contractions, like a sudden “jump”
- They occur in various forms of epilepsy but typically happen in children as part of juvenile myoclonic epilepsy.
Mild severity
Very short < 1 sec
Usually happen first thing after waking up
Generalised onset
Often associated with generalised tonic clonic seizures (happen before generalised tonic-clonic seziures
What is first line mx of myoclonic seizures [1]
Management is:
First line:
- sodium valproate
Other options:
- lamotrigine, levetiracetam or topiramate
Infantile Spasms
- This is also known as [] syndrome
Infantile Spasms
- This is also known as West syndrome
Describe the investigations used for epilepsy [+]
First-Line Investigations
- EEG: can detect interictal epileptiform discharges (IEDs), which indicate a high likelihood of epilepsy. Perform an EEG after the second simple tonic-clonic seizure. Children are allowed one simple seizure before being investigated for epilepsy.
- Magnetic Resonance Imaging (MRI): This imaging technique provides detailed images of brain structures and can identify abnormalities that may be causing seizures, such as tumours, vascular malformations or cortical dysplasias.
NB:
- While EEG and MRI are frequently used as initial investigations, they do not confirm epilepsy definitively. A normal EEG does not exclude epilepsy, nor does an abnormal EEG confirm it. Similarly, an MRI may show structural changes in the brain but these need to be interpreted in the context of clinical findings.
