Paediatric neurology (seizures) Flashcards
What is the difference between seizures and convulsions?
Seizure - any sudden attack from whatever cause - not all seizures are epileptic
Convulsions - seizure with prominent motor activity
What is a convulsive syncope?
Sometimes when kids (and adults) faint - at the end they can have random movements which are convulsive in nature
This is not seizure activity but looks similar and is called convulsive syncope
What is an epileptic seizure?
An abnormal excessive hypersynchronous discharge from a group of (usually cortical) neurones
May cause a paroxysmal change in motor, sensory or cognitive function
What determines the clinical manifestations of an epileptic seizure?
Depends on seizure’s location, degree of anatomical spread over cortex, duration
Define epilepsy
A tendancy to recurrent, unprovoked, spontaneous epileptic seizures
Someone can have an epileptic seizure without having epilepsy - its only when recurrent that they would have epilepsy
As we know - not all seizures are epileptic
What are the other causes of seizures?
What are the mimic like seizures?
(ie what are the differentials for an epileptic seizure)
Acute symptomatic seizures*
Reflex anoxic seizures
Syncope (esp convulsive syncopes)
Parasomnias - eg night terrors
Behavioural stereotypies - in those with intellectual disabilities
PNES - Psychogenic non-epileptic seizures, aka pseudoseizures
(Note also Alcohol-withdraw seizures in adults tho)
What are the different causes of acute symptomatic seizures?
Hypoxia-ischaemia
Hypoglycaemia
Infection - Febrile convulsions, Meningitis, encephalitis
Trauma
What is a reflex anoxic seizure (RAS)?
Describe the typical history of this
Reflex anoxic seizure (RAS)
Non-epileptic seizure resulting from brief overstimulation of the Vagus nerve
Key part of the history is an identifiable trigger to the event - ie the child got a fright, then dropped and began seizing
What is a psychogenic non-epileptic seizure?
Psychogenic non-epileptic seizure (PNES)
watch how you say that one
aka pseudoseizures
Happens in teens
Basically an epileptic seizure - but without the electrical discharging of an epileptic seizure - thus isnt
What are febrile convulsions?
Seizure occurring usually between 3 months and 5 years of age
Associated with fever but without evidence of intracranial infection or defined cause for the seizure
Commenest cause of acute symptomatic seizure in children
The following words are used to describe patterns of seizure activity - what do they mean?
a) Tonic
b) Atonic
c) Clonic
d) Myoclonic
Note - many are used together eg tonic clonic seizures
a) Tonic - characterised by stiffness
b) Atonic - complete lack of tone (ragdoll)
c) Clonic - refers to jerking
d) Myoclonic - brief jerks
What are the main types of seizure?
(absence seizures etc)
Absence seizure
Myoclonic (jerk) seizure
Atonic seizure
Generalized tonic-clonic seizure
(may be more - not sure)
Describe an absence seizure?
Very brief & abrupt (couple of seconds)
Eyes roll back & Eyelids up
Some blinking
No jerking or anything
Describe a myoclonic (jerk) seizure
Very brief (easy to miss)
Small number of large jerks - often leading to the patient dropping things
Describe an atonic seizure
Patient will all of a sudden go limp (like a ragdoll)
Will often cause serious injury to the patient due to falling
Describe a generalised tonic-clonic seizure
Much longer than previous examples
Characterised by extreme stiffness (tonic) with repetitive jerking (clonic)
Describe the mechanism of an epileptic fit and how this is recordable on an EEG
Excessive & hypersynchronous electrical discharge which is…
Chemically triggered by:
- decreased inhibition by GABA
- increased excitation by glutamate & aspartate
- excessive influx of Ca & Na
This chemical inbalance causes electrical currents which summate and result in depolarisation of many neurones - leading to a seizure
This can all be recorded on an EEG
What are the 2 groups of epileptic seizures?
Partial (focal) & generalised
How does childhood epileptic seizures/epilepsy differ from that of adults?
Majority are idiopathic in origin
Majority of childhood are generalised in nature
Childhood seizures can be subtle (absence seizures, myoclonus, drop attacks)
Describe the stepwise approach to diagnosing epilepsy in a child who has presented with a paroxysmal event
1) Is the paroxysmal event epileptic in nature?
2) Is it epilepsy? ie is it recurrent
3) What seizure types are occuring?
4) What is the epilepsy syndrome? eg Childhood absence epilepsy (CEA)
5) What is the aetiology?
6) Social and educational effects?
Give an overview of the diagnosis of Epilepsy
History +/- video of event
Interictal / ictal EEG
If indicated:
ECG
MRI Brain
Genetic testing
Metabolic tests
What additional investigation is needed if a child is having convulsive seizures?
Why?
ECG
To exclude Long QT syndrome - which can also cause convulsive seizures
Why would MRI be indicated for investigating potential epilepsy?
MRI brain - used to investigate aetiology if there are indications of brain malformations or brain damage
What is the purpose of genetics testing in the diagnosis of Epilepsy?
Genetics testing is being increasingly used to identify familial trends in idiopathic epilepsy
There are also single gene disorders associated with epilepsy - eg Tuberous sclerosis
