Paediatric neurology (seizures)

Question 1

What is the difference between seizures and convulsions?

Answer 1

Seizure - any sudden attack from whatever cause - not all seizures are epileptic

Convulsions - seizure with prominent motor activity

Question 2

What is a convulsive syncope?

Answer 2

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

Question 3

What is an epileptic seizure?

Answer 3

An abnormal excessive hypersynchronous discharge from a group of (usually cortical) neurones

May cause a paroxysmal change in motor, sensory or cognitive function

Question 4

What determines the clinical manifestations of an epileptic seizure?

Answer 4

Depends on seizure’s location, degree of anatomical spread over cortex, duration

Question 5

Define epilepsy

Answer 5

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

Question 6

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)

Answer 6

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)

Question 7

What are the different causes of acute symptomatic seizures?

Answer 7

Hypoxia-ischaemia

Hypoglycaemia

Infection - Febrile convulsions, Meningitis, encephalitis

Trauma

Question 8

What is a reflex anoxic seizure (RAS)?

Describe the typical history of this

Answer 8

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

Question 9

What is a psychogenic non-epileptic seizure?

Answer 9

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

Question 10

What are febrile convulsions?

Answer 10

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

Question 11

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

Answer 11

a) Tonic - characterised by stiffness
b) Atonic - complete lack of tone (ragdoll)
c) Clonic - refers to jerking
d) Myoclonic - brief jerks

Question 12

What are the main types of seizure?

(absence seizures etc)

Answer 12

Absence seizure

Myoclonic (jerk) seizure

Atonic seizure

Generalized tonic-clonic seizure

(may be more - not sure)

Question 13

Describe an absence seizure?

Answer 13

Very brief & abrupt (couple of seconds)

Eyes roll back & Eyelids up

Some blinking

No jerking or anything

Question 14

Describe a myoclonic (jerk) seizure

Answer 14

Very brief (easy to miss)

Small number of large jerks - often leading to the patient dropping things

Question 15

Describe an atonic seizure

Answer 15

Patient will all of a sudden go limp (like a ragdoll)

Will often cause serious injury to the patient due to falling

Question 16

Describe a generalised tonic-clonic seizure

Answer 16

Much longer than previous examples

Characterised by extreme stiffness (tonic) with repetitive jerking (clonic)

Question 17

Describe the mechanism of an epileptic fit and how this is recordable on an EEG

Answer 17

Excessive & hypersynchronous electrical discharge which is…

Chemically triggered by:

1. decreased inhibition by GABA
2. increased excitation by glutamate & aspartate
3. 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

Question 18

What are the 2 groups of epileptic seizures?

Answer 18

Partial (focal) & generalised

Question 19

How does childhood epileptic seizures/epilepsy differ from that of adults?

Answer 19

Majority are idiopathic in origin

Majority of childhood are generalised in nature

Childhood seizures can be subtle (absence seizures, myoclonus, drop attacks)

Question 20

Describe the stepwise approach to diagnosing epilepsy in a child who has presented with a paroxysmal event

Answer 20

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?

Question 21

Give an overview of the diagnosis of Epilepsy

Answer 21

History +/- video of event

Interictal / ictal EEG

If indicated:

ECG

MRI Brain

Genetic testing

Metabolic tests

Question 22

What additional investigation is needed if a child is having convulsive seizures?

Why?

Answer 22

ECG

To exclude Long QT syndrome - which can also cause convulsive seizures

Question 23

Why would MRI be indicated for investigating potential epilepsy?

Answer 23

MRI brain - used to investigate aetiology if there are indications of brain malformations or brain damage

Question 24

What is the purpose of genetics testing in the diagnosis of Epilepsy?

Answer 24

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

Question 25

When would metabolic testing be indicated in the diagnosis of epilepsy?

Answer 25

if associated with developmental delay/ regression

Question 26

When is use of Anti epileptic drugs indicated in epilepsy?

Answer 26

Only used once diagnosis is properly made - never before (even if obvious)

Question 27

What are the first line anti-epileptic drugs (AEDs) for the treatment of generalised epilepsies?

Answer 27

Girls = Levetiracetam

Boys = Sodium Valproate

Sodium valproate associated with neurodevelopmental delay in girls

Question 28

What is the first line anti-epileptic drug for Focal epilepsy?

Answer 28

Carbamazepine

Question 29

When is epilepsy defined as ‘drug resistent epilepsy’ - and what is the next step in the management of this?

Answer 29

Having tried 2 AEDs with no effect at controlling seizures

Consider alternative therapies such as:

• Immunomodulation - using steroids or immunoglobulins
• ketogenic diet
• epilepsy surgery (rarely)

Question 30

What are the different options for epilepsy surgery?

Answer 30

VNS - vagal nerve stimulation

Subdural grid electrode & resection of causative area