Neurology: Epilepsy Flashcards
What is epilepsy?
A tendency to intermittent abnormal electrical brain activity
A chronic disorder of the brain characterised by recurrent, unprovoked epileptic seizures
An epilepsy can be recognised after 2 or more UNPROVOKED epileptic seizures have occurred
The abnormal neuronal activity during an epileptic seizure can be manifest as…
Motor, sensory, autonomic, cognitive or psychic disturbance
A convulsion is a subtype of seizure in which motor activity occurs
In epilepsy, a diagnosis is made in a patient whom epileptic seizures recur spontaneously. An epileptic seizure can be provoked in individuals who do not have epilepsy. True or false?
True
Provoking insults: hypoglycaemia, fever, trauma, hypoxia
What percentage of children will have had a seizure (not associated with a fever) by 14?
1%
When classifying epileptic seizures, the initial division is into:
Generalised - involve both cerebral hemispheres
Partial - start in and affect one part of the brain
Partial seizures are further classified into…
Simple - consciousness retained
Complex - consciousness lost
Can a partial seizure become secondarily generalised?
Yes
What types of generalised seizures are there?
Tonic clonic - limbs stiffen (tonic) then jerk forcefully (clonic), LOC, usually around 1 to 3 minutes
Absence - brief e.g 10 second pauses, eyes may roll up, unaware and continue what they were doing, LOC
Myoclonic - sudden jerk, usually involve both sides of body and the person may fall over. Often after waking or when tired. Very short LOC.
Atonic - all muscle tone lost and drop to ground, quickly become conscious again, risk of injury, in babies often appear as head drop
Tonic - muscles stiffen, if standing they will usually fall backwards, no jerking, LOC, more common in childhood but considered uncommon
Describe West syndrome (infantile spasms)
Age of onset:3-12 months
Sudden flexion in a tonic fashion of head, trunk and limbs followed by extension of the arms
Can happen singly, but far more common to occur in clusters
Often on waking or many times per day
Common for infants to become irritable and go off feeds, social interaction deteriorates
May be misinterpreted as colic
In West syndrome what is the characteristic EEG pattern called?
Hypsarrythmia
A very disorganised pattern
The EEG is always abnormal in West syndrome but sometimes only seen during sleep
If West syndrome goes undiagnosed for many weeks, what can happen?
The child’s development may slow or go backwards
Drop in IQ in approximately 70%
Many of the problems will improve if spasms can be controlled and EEG improves
What are the main treatments for West syndrome/ infantile spasms?
Prednisolone first line
Vigabatrin second line
Some respond better with combination of both
Idiopathic generalised epilepsy (IGE) defined syndromes include:
Benign familial neonatal convulsions
Childhood absence epilepsy CAE
Juvenile absence epilepsy JAE
Juvenile myoclonic epilepsy JME
There is no apparent cause expect for genetic predisposition
Symptomatic generalised epilepsy defined syndromes include:
Infantile spasms (west syndrome)
Lennox- Gastaut syndrome
Cerebral malformations
Progressive myoclonic epilepsies
The cause is known or suspected in these
What is the cause?
In about 50% of children, no cause will be identified
Infection Hyponatraemia Hypoglycaemia Hypocalcaemia Hypomagnesia Toxins Trauma Metabolic defects Tuberous sclerosis CNS tumour or malformation
How is epilepsy diagnosed?
Careful and complete history - event before, during and after seizure
Video recording is useful
Distinguish true seizures from the many paroxysmal disturbances that can mimic them - reflex anoxic seizures, vasovagal syncope, cardiac dysrhythmia
Physical examination - often normal, but pay attention to skin (neurocutaneous syndromes) and to fundus as retinal changes can provide clue to aetiology
Imaging
What investigations can be done?
ECG standing for all children with seizures, even when epilepsy seems most likely (the consequences of missing convulsive syncope due to an arrhythmia can be fatal
EEG - may be useful to aid diagnosis (but a routine interictal EEG does not prove or disprove diagnosis)
If seizures frequent then an ictal EEG can make diagnosis
A sleep or sleep deprived EEG may be helpful, or 24h ambulatory EEG
MRI and CT brain scans generally required unless characteristic history
PET/SPECT - detect areas of abnormal metabolism, which could be epileptogenic areas
How should epilepsy be managed?
Education - both child and parent
Encourage to participate in and enjoy full social life, discourage overprotection
Percussions: swimming, bath, cycling, climbing
Consider psychological implications
Learning difficulties present in proportion of children with epilepsy, but only minority require special schooling
Anti Epileptic Drugs
- not all children with epilepsy require them
- many would not start AEDs after a single brief tonic clonic or for infrequent myoclonic or absence
- commonly used : sodium valproate and carbamazepine
- newer AEDs being increasing used : lamotrigine, topiramate, vigabatrin
What is currently the first line treatment for generalised epilepsy?
Sodium valproate
What is the current first line treatment for partial epilepsy?
Carbamazepine
Mono therapy will achieve total seizure control in what percentage of children?
70%
What side effect is vigabatrin associated with?
Permanent visual field defects
In those with infantile spasms, is there usually an underlying cause?
Yes, a particular cause will be found in 7/8 out of 10 children
Is Lennox-Gastaut epilepsy common?
No
It is the most common type of intractable (difficult to treat) childhood epilepsy
What is Lennox-Gastaut epilepsy also known as?
Epileptic and developmental encephalopathy - because the seizures and abnormal EEG thought to be important in the developmental delay and learning difficulties
What is the most common age of onset of Lennox-Gastaut syndrome?
1-3 years
Describe the seizure pattern in Lennox-Gastaut syndrome
Multiple seizure types, but mostly atonic and tonic seizures Child may suddenly fall to ground, injuries often occur and usually happen several times per day Also atypical (subtle) absence seizures - appear vacant, unable to speak, drooling, floppy
In Lennox-Gastaut syndrome, do children have developmental delay?
Yes or learning difficulties
Before or after seizures start
About how many children will develop Lennox-Gastaut syndrome after West syndrome?
2/3 out of 10
What does the EEG typically show with Lennox-Gastaut syndrome?
Inter-ictal: slow spike and slow wave activity
Ictal EEG during tonic seizure: fast spike activity
What can cause Lennox-Gastaut syndrome?
Genetic conditions e.g tuberous sclerosis
Brain malformation
Previous brain damage - HIE, meningitis as a young baby or head injury
In about half, no cause found
Describe childhood absence epilepsy
Age of onset 4-12 years
Momentary unresponsive stare with motor arrest, may have minimal eyelid/ mouth
Sudden onset, lasts a few seconds
Child has no recall, except realises they have missed something
Happen less often when child is focused on an activity
Is childhood absence epilepsy associated with developmental delay?
No, but can interfere with schooling
How is it diagnosed?
History
Episodes induced by hyperventilating- blowing on piece of paper/windmill for 2-3 mins
EEG shows fast generalised spike and wave discharges, during and sometimes between absences
No other tests such as scans required, unless atypical features
Does CAE usually respond well to treatment?
Yes
Ethosuximide, SV and lamotrigine
Occasionally combination of 2
What is the prognosis for CAE?
Majority become seizure free as they pass through puberty
A few evolve in juvenile absence or juvenile myoclonic epilepsy
Benign Rolandic epilepsy (childhood epilepsy with centro-temporal spikes) is one of the most common types of epilepsy in children. True or false?
Yes = 15% of childhood epilepsies
It affects boys slightly more than girls
When does childhood Rolandic epilepsy start and stop?
Usually starts between 4-10 years and stops around puberty
Describe benign Rolandic epilepsy
Usually focal seizures
Often start as child is asleep or just about to wake
Tingling on one side of mouth, speech abnormality, gurgling noises
Occasional spreads to bilateral tonic clonic seizure, child may be incontinent and sleepy afterwards
Do not usually have LDs
What does the EEG show with benign Rolandic epilepsy?
Focal sharp waves from the Rolandic area (centro-temporal)
Important to recognise as relatively benign and may not require AEDs
Describe Panayiotopoulos syndrome (early onset benign occipital epilepsy)
Age of onset: 1-5 years
Autonomic features with vomiting and unresponsive staring in sleep
Pupils dilate, face flushed, sweating and drooling
Head and eye deviation
Progressing sometimes to a convulsive seizure
Remits in adolescence
Relatively benign and may not need AEDs
Describe juvenile absence epilepsy
Age of onset: 10-20 years
Absences and generalised tonic clonic seizures
Often with photosensitivity
Characteristic EEG
Response to treatment usually good, but lifelong
Remission unlikely
Learning unimpaired
Describe juvenile myoclonic epilepsy
Onset: 10-20 years
Myoclonic seizures, generalised tonic clonic and absence may occur
Mostly shortly after waking
Typical history: throwing drinks and cereal about
Learning unimpaired
Characteristic EEG
Response to treatment usually good but lifelong
Remission unlikely
The decision of whether to treat or not is related to…
Risk of reoccurrence
How dangerous or impairing
How upsetting further seizure would be
Carbamazepine can make what seizures worse?
Absence and myoclonic
What is the desired goal of treatment with AEDs?
Mono therapy at minimum dose to prevent seizures without adverse effects
In practice more than 1 AED may be required
Children with prolonged seizures with LOC more than 5 mins are given what?
Rescue therapy - usually buccal midazolam
When can AEDs be discontinued?
After 2 years seizure free
Usually continued indefinitely if juvenile absence or juvenile myoclonic epilepsy
In children with intractable epilepsies, what other treatment options are there?
Ketogenic diet (low carb, fat based)
Vagal nerve stimulation
Epilepsy surgery if well localised, structural cause:
- temporal lobectomy for mesial temporal sclerosis
- hemispherotomy
- focal resections
