Epilepsy 2 Flashcards
Define
The recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifesting in seizures
Epilepsy is an ongoing liability to recurrent epileptic seizures
Chronic disorder
Define epileptic seizure
Paroxysmal/unprovoked event in which changes of behaviour, sensation or cognitive processes are caused by excessive, hypersynchronous (unusually synchronised) neuronal discharges in the brain
What are convulsions
Motor signs of electrical discharges
Give example of an abnormal metabolic circumstance that would result in a seizure
Low Sodium
Hypoxia
Since epilepsy is a chronic disorder, what does this mean for diagnosis
Need at least 2 seizures to be defined as epileptic
Epidemiology
Common
Incidence is age-dependent, it is highest at the extremes of life with most cases starting before 20yrs or after the age of 60yrs
Canoften go into remission
How long do epileptic seizures usually last
30-120 seconds
How many epileptic seizures are idiopathic
2/3rds are idiopathic, often familial
Aetiology - the 1/3 not idiopathic
Cortical scarring Space-occupying lesion e.g. tumour Stroke Tuberous sclerosis Alzheimer’s or dementia - epilepsy more common Alcohol withdrawal
Examples of cortical scarring that can cause epileptic seizures
- Head injury years before onset
- Cerebrovascular disease e.g. cerebral infraction or haemorrhage
- CNS infection e.g. meningitis or encephalitis
Risk factors
- Family history
- Premature born babies who are small for their age
- Abnormal blood vessels in brain
- Alzheimer’s or dementia
- Use of drugs e.g. cocaines
- Stroke/brain tumour/infection
Elements of a seizure
Prodrome
Aura
Post-ictally (after seizure)
What is prodrome and how long does it last
Lasting hours or days may rarely precede the seizure
Not part of the seizure, results in change of mood or behaviour
What is aura
Part of seizure where the patient is aware and may precede its other manifestations
Strange feeling in the gut, deja vu or strange smells or flashing lights
(not necessarily due to temporal lobe damage)
Describe post-ictally (after seizure)
Headache, confusion, myalgia and a sore tongue
Temporary weakness after a focal seizure in motor cortex - Todd’s palsy
Dysphasia following a focal seizure in the temporal lobe
What is Todd’s palsy
Temporary weakness after a focal seizure in motor cortex
Classifications of seizures
Primary generalised (40%) Partial/focal seizures (57%)
Describe Primary generalised seizure
Simultaneous onset of electrical discharge throughout whole cortex (involving both hemispheres), with no localising features referable to only one hemisphere
Bilateral symmetrical and synchronous motor manifestations
Always associated with loss of consciousness or awareness
Describe partial/focal seziures
Focal onset, with features referable to a part of one hemisphere e.g. temporal lobe
Often seen with underlying structural disease
Electrical discharge is restricted to a limited part of the cortex of one cerebral hemisphere
These may later become generalised (e.g. secondarily generalised tonic-clonic seizures)
Types of primary generalised seizures
Generalised tonic-clonic seizure Typical absence seizure Myoclonic seizure Tonic seizure Atonic (akinetic) seizure
Describe the Tonic and Clonic phase of generalised tonic-clonic seizure
Tonic phase = Rigid, stiff limbs - person will fall to floor if standing
Clonic phase = Generalised, bilateral, rhythmic muscles jerking lasting seconds-minutes
Describe clinical presentation of Generalised Tonic-Clonic seizure
Often NO aura Loss of consciousness Tonic and Clonic phase Eyes remain OPEN Tongue often bitten May be incontinence of urine/faeces
What follows a Generalised Tonic-Clonic seizure
period of drowsiness, confusion or coma for several hours post-ictally
Describe clinical presentation of Typical Absence seizure
- Usually a disorder of childhood
- Child ceases activity, stares and pales for a few seconds only
- I.e. suddenly stops talking in mid-sentence, then carries on where left-off
- Often do not realise that they’ve had an attack
- Children with petit mal tend to develop generalised tonic-clonic seizures in adult life
How would you characterise a typical absence seizure
On EEG characterised by a 3-Hz spike and wave activity
Clinical presentation of myoclonic seizure
Sudden isolated jerk of a limb, face or trunk
Patent may be thrown suddenly to the ground, or have a violently disobedient limb
Clinical presentation of tonic seizure
Sudden sustained increased tone with a characteristic cry/grunt
Intense stiffening of body (tonic)
Stiffening NOT FOLLOWED by jerking
Clinical presentation of atonic seizure
Sudden loss of muscle tone and cessation of movement resulting in a fall
Examples of partial/focal seizures
Simple partial seizure
Complex partial seizure
Partial seizure with secondary generalisation
Clinical presentation of Simple partial seizure
Not affecting consciousness or memory
Awareness is unimpaired with focal motor, sensory (olfactory, visual etc.), autonomic or psychic symptoms
No post-ictal symptoms
Clinical presentation of Complex partial seizure
- Affecting awareness or memory before, during or immediately after the seizure
- Most commonly arise from the temporal lobe (understanding speech, memory & emotion)
- Post-ictal confusion is common with seizures arising from the temporal lobe, whereas recovery is rapid after seizures in the frontal lobe (thought processing & movement)
Clinical presentation of Partial seizure with secondary generalisation
In 2/3rds of patients with partial seizures, the electrical disturbance, which starts focally (as either a simple or complex partial seizure), SPREADS WIDELY causing a secondary generalised seizure which is typically convulsive
Characteristics of partial/focal seizure depend on lobe affected.
Clinical presentation of partial seizure if temporal lobe affected
memory, emotion & speech understanding
Aura (80%) - Deja-vu, auditory hallucinations, funny smells, fear
Anxiety or out of body experience, automatisms e.g. lip smacking, chewing, fiddling
Characteristics of partial/focal seizure depend on lobe affected.
Clinical presentation of partial seizure if frontal lobe affected
motor and thought processing
Motor features such as posturing or peddling movements of the
leg
Jacksonian march - seizure “marches” up or down the motor
homunculus starting in face or thumb
Post-ictal Todd’s palsy - paralysis of limbs involved in seizure for
several hours
Characteristics of partial/focal seizure depend on lobe affected.
Clinical presentation of partial seizure if parietal lobe affected
Interprets sensations
Sensory disturbances - tingling/numbness
Characteristics of partial/focal seizure depend on lobe affected.
Clinical presentation of partial seizure if occipital lobe affected
Vision
Visual phenomena e.g. spots, lines or flashes
Functions of each lobe of cerebrum
Frontal - motor and thought processing
Temporal - memory, emotion & speech understanding
Parietal - interprets sensations
Occipital - vision
What is syncope
loss of consciousness due to hypoperfusion to brain
Difference in presentation between epilepsy and syncope
Epilepsy - Tongue biting, head turning, muscle pain, loss of consciousness, cyanosis, post-ictal symptoms
Syncope - Prolonged upright position e.g. long time standing, sweat prior to loss of consciousness, nausea, pre-syncopal symptoms
Difference between epileptic and non-epileptic seizure
Non-epileptic seizures are situational
Non-epileptic is longer, closed mouth/eyes during tonic-clonic movements, pelvic thrusting, do not result from sleep, no incontinence or tongue biting
There are pre-ictal anxiety symptoms in non-epileptic seizure
Differential diagnosis
Postural syncope Cardiac Arrhythmia TIA Migraine Hyperventilation Hypoglycaemia Panic attacks Non-epileptic seizure
Clinical diagnosis
from history there needs to be at least 2 or more unprovoked seizures occurring > 24hrs apart to DIAGNOSE EPILEPSY
Diagnosis
Electroencephalogram MRI (imaging of hippocampus) CT head Blood tests - FBC, electrolytes, Calcium, Renal function, Liver function, Urine biochemistry, blood glucose levels Genetic testing
WHat is the purpose of of an electroencephalogram
Not diagnostic but can support a clinical diagnosis
May also help determine seizure type and what epilepsy syndrome
What is the purpose of CT head
Rule out metabolic causes and discover comorbidities
Give example of when genetic testing can be used
juvenile myoclonic epilepsy
What are AEDs
Anti-Epileptic Drugs - help control seizures in about 70% of people
Common types of Anti-epileptic drugs
sodium valproate carbamazepine lamotrigine oxcarbazepine ethosuximide
Side effects of AEDs
drowsiness a lack of energy agitation headaches uncontrollable shaking (tremor) hair loss or unwanted hair growth swollen gums rashes
When would surgery be an option for treatment
AEDs aren’t controlling your seizures
Tests show that your seizures are caused by a problem in a small part of your brain that can be removed without causing serious effects
What tests are done before surgery
Brain scans
Electroencephalogram - a test of your brains electrical activity
Tests of your memory, learning abilities and mental health
Medical treatment of Generalised Tonic Clonic seizure
AEDs: Sodium valproate (not in child bearing age women); Lamtrigine
Seizure control: Diazepam (or Lorazepam)
Medical treatment of Absence seizure
AED:
Sodium valproate
Ethosuximide
Medical treatment of Partial seizure
AED: Lamotrigine carbamazepine; Phenytoin
Seizure control: Diazepam (or lorazepam)
What other procedures can be done if AEDs aren’t controlling your seizures and brain surgery isn’t suitable for you
Vagus nerve stimulation (VNS)
Deep brain simulation (DBS)
Ketogenic diet
What is Vagus Nerve Stimulation (VNS)
A small electrical device (similar to a pacemaker) is placed under skin of chest
A wire connects it to the vagus nerve and bursts of electricity are sent along the wire
Helps control seizures by changing electrical signals in brain
Side effects of vagus nerve stimulation
Hoarse voice
Sore throat
Cough
What is deep brain simulation and what are side effects
Similar to VNS
Wires run directly into brain
Bursts of electricity sent along these wires can help prevent seizures by changing the electrical signals in the brain
1st line treatment of partial seizure
CARBAMAZEPINE
What is SUDEP
Sudden unexpected death epilepsy
More common in uncontrolled epilepsy
Treatment in emergency measures
Ensure patient harm themselves as little as possible - ABCDE
Check glucose
Prolonged seizure (longer than 3 minutes) or repeated seizures are treated with RECTAL/IV DIAZEPAM or LORAZEPAM - repeat x2
IV PHENYTOIN LOADING
If still fitting then anaesthetist involvement for anaesthetic and ventilation
Generally drugs are NOT advised after just one fit, but when would you consider giving drugs anyway
If risk of recurrence is high
