Seizures - Paediatric Neurology

Seizures

·        Classification:

o  Either partial or generalised

o  And one of:

§  Acute symptomatic: any person in that situation would seize eg hypoglycaemia, heatstroke, meningitis, hyponatraemia. Seizure will stop when cause goes away (unless scarring – when it becomes a „remote symptomatic‟ seizure) 

§  Single

§  Benign Febrile Convulsion

§  Epilepsy: Repeated unprovoked seizures

o   If Epilepsy then:

§  Localised: Idiopathic, symptomatic or cryptogenic

§  Generalised: Idiopathic, symptomatic or cryptogenic

§  Unclassified

·        Seizures:

o   A symptom – not a diagnosis or a disease

o   Hyper-synchronous excessive discharge of CNS neurons associated with a clinical sign

·        Diagnostic process:

o   Is it a seizure or not

o   What type of seizures – is it generalised or localised, etc

o   Is it a single seizure, acute symptomatic, afebrile or epilepsy 

o   If epilepsy, what syndrome is it (this step is critical to treatment and prognosis, but often ignored in practice)

o   Brain tumours cause 1 – 2 % of all seizures in children, and 4 – 6% of partial seizures

·        Neuro-imaging:

o   Indicated for:

§  Neurological deficit/asymmetry

§  Neurocutaneous syndrome

§  Developmental regression

§  Partial seizures

§  Infantile spasms or myoclonic seizures in 1^st year of life

§  Persisting unclassifiable seizures

o   Not indicated for:

§  Idiopathic generalised epilepsy

§  Benign childhood epilepsy with centrotemporal spikes (Rolandic)

§  Simple Febrile Seizures

o   CT:

§  Initial scanning technique for exclusion of tumour

§  Show calcification

§  Available and easier to perform

o   MRI:

§  Preferred imagining technique

§  Sensitive to migrational abnormalities or very small lesions

o   PET/SPECT scan: localise lesion on the basis of metabolism.  Only if considering epilepsy surgery

Epilepsy in Childhood

·        Incidence: 0.5 – 1 %

·        Lifetime prevalence of a seizure is 5%

·        Aetiology: 

o   Idiopathic: normal kids, no structural abnormality, often family history, EEG normal, generally benign and good prognosis. Cause is assumed to be genetic – usually a channelopathy

o   Symptomatic: An underlying cause is known, and there are usually other signs of a problem 

o   Cryptogenic: There are other problems besides seizures, eg retardation, focal signs, etc, but can‟t find a cause 

o   Symptomatic and Cryptogenic: abnormal children, abnormal background on EEG, prognosis not so good and often seizures difficult to control 

·        Benign focal (Rolandic) Epilepsy of Childhood:

o   = Benign Childhood Epilepsy with Centrotemporal Spikes

o   Commonest focal seizures in children

o   Onset 3 – 10 years

o   80% focal, especially mouth and face.  50% only have fits in sleep

o   EEG diagnostic.  Prognosis excellent

·        Childhood absence epilepsy:

o  Onset 4 – 10 years – often confused with daydreaming

o  Almost all outgrow the absence seizures, but 30% will have GTCS in adolescence

o  Usually easily treated

·        EEG:

o  Need to do when sleep deprived and not on medication

o  2 – 4 % of normal children have an abnormal EEG

o  55% of epileptic children have an abnormal EEG

o  Looking at frequency, morphology, location, reactivity, symmetry, dysrhythmia, etc

o  Paroxysmal events:

§  Noises

§  Benign variants: associated with age and state

§  Epileptiform: inter-ictal and ictal 

·        Psychosocial aspects: More important than drugs. Peoples attitudes will do far more damage than a few seizures

o  Education

o  Counselling

o  Normalising

·        Seizure precautions: when driving, swimming, bathing, scuba diving, etc

·        Pharmacology:

o  Aim:

§  Seizure free with no side effects

§  Start low and go slow

§  Never stop abruptly

§  Start after 2 or more seizures

§  Stop after 2 years seizure free

o  Common drugs:

§  Carbamazepine

§  Valproic acid

o  Less common:

§  Clobazam

§  Ethosuximide

§  Phenytoin

§  Phenobarbitone

o  Rarer:

§  Vigabatrin

§  Lamotigine

·        Status Epilepticus:

o  Continuous or intermittent fitting > 30 mins

o  ABCDEFG – does airway need protecting 

o  Give effective anticonvulsant – 2 doses of rectal diazepam, if it continues consider paraldehyde, phenytoin, general anaesthesia

Benign Febrile Convulsion

·        Types of seizure occurring with fever:

o  Benign febrile convulsion

o  Epilepsy: eg first epileptic seizure unmasked by fever

o  Acute symptomatic seizure: meningitis, etc

·        Benign Febrile Convulsions:

o  Frequency: 2 – 5% of all children

o  Age: 6 months – 5 years

o  Temperature: usually > 38.5 C

o  Boys: Girls = 1.4:1

o  Family history common (polygenic inheritance)

o  Unrelated to prenatal and perinatal brain damage

o  Have seizures with fever only

o  Treatment:

·        Stop seizure: rectal diazepam (0.5 mg/kg) at home or in ambulance

§  Find the cause of the fever: seizure won‟t hurt them but meningitis might! 

§  DON‟T use anticonvulsants – decrease recurrences but potentially significant side effects to treat something that is benign 

o   Prevention: Avoid over heating.  Paracetamol/ibuprofen or tepid sponging don‟t ¯risk of seizure 

o   Types:

§  Simple (75%): generalised, brief (< 15 minutes), does not recur in 24 hours

§  Complex (25%): Focal and/or prolonged and/or recurrence within 24 hours

o   Recurrence: 30% will have a recurrence, 70% of these within the next year

o   Risk of subsequent epilepsy: 

§  Increased risk if neurologically abnormal prior, family history of epilepsy or first seizure is complex

§  Otherwise very slight increase in risk only

o   Neurological sequalae:

§  No impact on behaviour, growth, IQ 

§  Prolonged febrile seizures associated with hippocampal sclerosis (temporal lobe). Controversial. (eg which direction is causation)

·        Parental education:

o   Seizure does not cause brain damage (if less than 30 – 45 minutes)

o   30% chance of another seizure

o   Next time: stay clam, clear airway, recovery position when stopped (low tone), time the seizure

o   Call ambulance at 5 minutes:

§  Most seizures stop by 5 minutes – so those that haven‟t are more likely to go on for longer

§  Want to be at hospital and have it stopped by 45 minutes

Anoxic Seizures

·        White breath-holding attacks: 

o   Vaso-vagal events due to stimulus: eg anger, pain, vomiting, etc. [Big sympathetic drive ® parasympathetic overcompensation????] 

o   Occur in children from 2 – 10

o   Reflex bradycardia or brief asystole or peripheral vasodilation 

o   Symptoms: pallor, ocular revulsion, don‟t breath, extensor posture, a few symmetrical clonic movements, spontaneous resolution and then fine

·        Blue breath-holding attacks:

o   1 – 5 years

o   Follow a stimulus, eg crying

o   Get worked up, don‟t breath in, run out of breath and don‟t breath in (actually stop breathing)

o   Cyanosis with retained heart rate

o   May lose consciousness and have some clonic movements

o   Blow on face to start breathing

·        Both white and blue breath holders are often iron deficient ® do dietary history and Hb test

·        Don‟t treat them.  Ensure parent isn‟t being manipulated by breath-holding by child