Epilepsy and seizures Flashcards
What is the definition of a seizure?
- The action of capturing someone or something using force
Medical definition : The manifestation of an abnormal hypersynchronous discharge of a population of cortical neurones
What is the definition of epilepsy?
A disorder of the brain characterised by an enduring predisposition to generate seizures and the neurobiologic, cognitive, pyschological and social consequences of this condition
When do seizures occur?
- When you have excessive brain electrical activity
- The propensity for recurrent, unprovoked seizures
- Tonic - clonic seizure =
- Tonic : tense or rigid muscles
- Clonic : sustained rhythmical jerking movements
Explain epilepsy
- The tendency for recurrent unprovoked seizures
- More of a symptom of disease than a disease itself
- Epiletics have more excitable brains due to:
- Structural abnormality (tumours, scars)
- Cogenital anomaly :
- Channelopathies (ion channel dysfunction)
- Abnrmal cortical neural networks
- Provoked seizures = single seizure events that result from an immediately recognisable stimulus or cause e.g. head injury, strokem alcohol/ drug withdrawl, fever, hypoglycaemia, brain infection. Seizures do not happen in the absence of the stimulus and thus are not epilepsy.
What are epilepsy syndromes defined by?
Defined by a group of features usually occurring
together e.g.
* Age when seizures begin
Genetics
Responses to medication
* Clinical course
* Brain focus involved
* EEG findings
Seizure type
Juvenile myoclonic syndrome
*
* Childhood & juvenile absence
epilepsy
Temporal lobe epilepsy
*
Benign Rolandic Epilepsy
*
Why is it important to be able to classify seizures?
- Management - choice of medication
- Prognostication
- Investigation (could provide a useful link to specific syndromes)
- Trials and research
- Provides words to patients to describe their disease
What are the diffferent classification of seizure types?
- Focal onset : Aware/ Impaired awareness . Motor/ Non motor - focal to bilateral tonic-clonic (Starts at a focal point and spreads to opposite hemisphere). Arises from a discrte cortical focus .
- Generalised onset : Impaired awareness. Motor. Tonic-clonic or other motor, Non motor (abscence) . Affects both hemispheres of the brain at the same time.
- Unknown onset : Motor : Tonic- clonic , other motor, non-motor (abscence) = beginning of seizure is unknown. Not witnessed by anyone.
What are the different symptoms that happen during a seizurre?
For focal onset seizures:
Motor symptoms may include:
* Jerking (clonic)
* Muscles becoming limp or weak (atonic)
* Tense or rigid muscles (tonic)
* Brief muscle twitching (myoclonus)
* Epileptic spasms (body flexes and extends repeatedly).
* Automatisms or repeated automatic movements, like clapping or rubbing
of hands, lip-smacking or chewing, or running.
*Non-motor symptoms:
* Changes in sensation,
* Changes in emotions
* Changes in thinking or cognition
* Changes in autonomic functions (such as gastrointestinal sensations,
waves of heat or cold, goosebumps, heart racing, etc.),
* Lack of movement (called behavior arrest).
For generalized onset seizures:
*Motor symptoms may include:
* Sustained rhythmical jerking movements (clonic)
* Muscles becoming weak or limp (atonic)
* Muscles becoming tense or rigid (tonic)
* Brief muscle twitching (myoclonus)
* Epileptic spasms (body flexes and extends repeatedly).
*Non-motor symptoms are usually called absence seizures. These can be
typical or atypical absence seizures (staring spells). Absence seizures can also
have brief twitches (myoclonus) that can affect a specific part of the body or
just the eyelids.
For unknown onset seizures:
*Motor seizures are described as either tonic- clonic epileptic spasms.
*Non-motor seizures usually include a behavior arrest. This means that movement stops —
the person may just stare and not make any other movements.
What is consciousness?
- A system of cortical and sub cortical brain networks that work to maintain :
- Alertness
- Attention
- Awareness
- Disruption (impairement or complete loss of consciousness) = can be severely debilitating
Describe consciousness in focal onset seizures
Focal onset aware seizure (previously
simple partial seizures)
Consciousness is unaffected (person is
awake and aware) = EPILEPTIC AURA
Mainly seen in frontal lobe, occipital lobe
seizures
Focal onset Aware Can be motor or non-motor
- Focal epileptic discharge
— Motor (Jacksonian march)
— Sensory (tingling, burning)
e.g. disturbance of motor,
sensory, cognitive or autonomic
function
(déjå vu, hallucinations)
— Psychic
— Special sense (metallic taste, flashing lights, unpleasant smell)
— Autonomic (epigastric rising sensation) - Often there is a deficit after attack- Todd’s palsy
e.g. limb weakness in affected limb, speech aphasia
(Broca’s), visual field defects (occipital) or loss of sensation
Focal onset impaired awareness
(previously complex partial seizures)
Consciousness is affected (person is
confused or their awareness is affected)
Mainly seen in temporal lobe seizures
Often preceded by an aura
Often originate in the temporal lobe :
- Vocalisations (grunting etc)
- Posturing
- Wandering
- Automatisms - semi-purposeful movements
What are the 3 As of epilepsy?
- Aura (i.e may be initially fully conscious)
Altered consciousness (but usually partially responsive) - Automatisms (characteristic)
— Lip smacking
— Teeth grinding
— Fiddling with clothes, objects
Wandering, pacing, circling
‘Absence’ common, but typically not the sole feature
Typically the longest in duration
— Can be several minutes up to even an hour - Variable disorientation afterwards, amnesia for the event
What is myoclonus (generalised onset motor seizure)?
e.g. myoclonus (= generalised onset motor)
Myo = muscle
Clonic = jerks
Very brief (1 second)
* Shock-like
Muscle contraction
Usually bilateral
Falls
Full immediate recovery
* Loss of consciousness too brief to be appreciated
Occur in a number of epilepsy syndromes
Benign myoclonus occurs in healthy people e.g when falling asleep or hiccups.
This is not a myoclonic seizure.
What is the absence (generalised onset non motor)?
Typical
Most common
Brief (< 10 seconds)
Abrupt loss of consciousness
Unaware of episode
Full, immediate recovery
Vacant stare
Speech arrest
Tone usually unaffected
— If seated, maintain posture
— If walking, keep walking
No aura
Often missed / misinterpreted
(‘daydreaming’)
More common in children
Formerly petit mal
Atypical
Atypical because they may be
longer (20+seconds), have a
slower onset and offset,
involves different symptoms
Usually a change in muscle
tone and movement e.g.
Blinking/eyes flickering
Lip-smacking/chewing
Rubbing fingers
What is tonic - clonic (generalised onset motor)?
e.g. tonic-clonic (generalized onset motor)
Formerly grand mal
Possible aura (varied)
Ictus
— Tonic (rigid) phase (seconds) — driven by intense neuronal discharge from cerebral
cortex
* Flexion of arms -entire body become rigid
Cry — laryngeal and respiratory muscles force air out of the chest
Cyanosis — breathing ceases temporarily
— Clonic (jerking) phase (minutes)
* Jerking of limbs (muscular contraction and relaxation)
* Reducing frequency
* Intermittent/suspended breathing, hypersalivation appears as frothing at mouth
* Tongue biting (side of tongue)
* Urinary incontinence
Post-ictal period
Drowsy, disorientated
— Out of sorts for the rest of the day
T-C seizure lasting more than 5 minutes
is a medical emergency. Call 999.
A seizure that lasts more than 10
minutes, or three seizures in a row
without the person coming to between
them, is a dangerous condition. This is
called status epilepticus; emergency
treatment in a hospital is needed.
What is the structural aetiology of epilepsy?
Structural
Epilepsy can be symptomatic of a structural lesion e.g.
. Congenital
Acquired
-Tumour
-Vascular malformation
-Abscess
-Stroke
-Scarring
-Cysts
