Paroxysmal events (‘fits, faints and funny turns’) are frequently not witnessed by medical staff and so the diagnosis often rests on the description from the eyewitness observer or the child themselves if awareness was retained.
Important points to keep in mind include:
Never rely on a second person description for a diagnosis – always take a detailed history from the eyewitness.
Although these events are often stereotyped, most of the time they are not seizures and epilepsy is not a diagnosis of exclusion.
A detailed history often confirms the diagnosis without the need for further investigations.
A video of the event is invaluable! Ask the parents to record the episodes.
Identify each type of episode observed and give it a nickname.
For each type of episode, clarify:
Frequency – ‘how many in a day/week/month?’
Timing – ‘certain time of the day or behavioural states?’
Relationship to sleep – ‘on falling asleep, during sleep, waking?’
Triggers – ‘tired, travel, excitement, exercise?’
Warning beforehand – ‘clings to parent, aware of one coming on?’
Duration – ‘how long does it last and if clustered how long between episodes?’
Colour change – ‘pallor, early cyanosis?’
Alterations in conscious level – ‘change in responsiveness, can describe the event themselves?’
Motor phenomena – ‘can you act out exactly what happens, any directional movements/lateralization?’
Recovery and symptoms following the event – ‘how long does it take to recover, any changes from the normal child after?’
Family history – ‘does anyone in the family have similar looking episodes?’
Is this epilepsy? ¹
A seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Epilepsy is a disease of the brain defined by any of the following conditions:
At least two unprovoked (or reflex) seizures occurring more than 24 hours apart
One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years
Diagnosis of an epilepsy syndrome
Therefore a diagnosis of epilepsy requires the seizures to be recurrent and unprovoked (i.e. the absence of a temporary or reversible factor lowering the seizure threshold).
Epilepsy versus acute symptomatic seizures
Acute symptomatic seizures are a result of a number of acute insults, including hypoglycaemia, hypoxia, electrolyte derangements, infection, and trauma.
Focus on any known triggers in the history – think ‘before’, not ‘after’.
They may also be recurrent – the best know example being recurrent febrile seizures.
The role of EEG
Routine use of EEG is of limited value – false-positive rates can be high and inter-ictal EEGs are usually normal in epileptic patients.
Use EEG to answer the following questions:
What seizure types are occurring?
What is the epilepsy syndrome?
Types of seizures 2,3
Clonic – rhythmic contractions followed by a slower relaxation phase
Myoclonic – isolated brief, fast contractions followed by complete muscle relaxation
Spasms – slightly longer phase of sustained contraction, typically occurring in runs
Tonic – a prolonged period of contraction of one or several muscle groups
Atonic – sudden loss of muscle tone. Can cause the child to slump to the ground
Tonic and large myoclonicseizures can both cause children to fall
Absence – brief arrest of speech and activity (typically <5 sec). May show automatisms of lip-smacking, eyelid flickering. Occur many times in a day
Focal – can cause impaired awareness and unresponsiveness. Last longer (>30 sec) than absences and occur less frequently
Paediatric epilepsy syndromes
Epilepsy syndromes are defined almost entirely phenotypically on the basis of age of onset, seizure types, EEG findings, neurodevelopmental outcomes, response to anti-epileptic drugs, and so on.
It is useful to understand that there are a limited number of ways underlying pathology can manifest as dysfunction according to the maturation status of the brain.
Syndromic diagnoses take time and require specialist input.
Below are the more common paediatric epilepsy syndromes. Early recognition and referral is an important skill for anyone working with children.
Infantile spasms; West syndrome 4,5
Peak: 4 – 7 months
Can be as late as 12 months
Infantile spasms – sudden jerks of the neck, trunk or limbs followed by a few seconds of tonic posturing
Shortly after waking or when falling asleep
Clustered – several to hundreds in runs
Cries at the end of the run of spasms
Insidious onset with subtle spasms that increase over time
Encephalopathy/regression – loss of visual alertness and smile
West syndrome is a combination of infantile spasms, hypsarrhythmic pattern on EEG and regression.
Numerous prenatal, perinatal and postnatal aetiologies.