Summary
- A fit is an abnormal cerebral discharge - a dysrhythmia.
- A seizure is a paroxysmal alteration in behaviour due to various causes.
- The term convulsion is used when a child has a sudden episode of stiffening (decerebrate posturing) followed by clonic jerking.
- Recurrent fits usually reflect underlying structural brain lesions or one of several specific seizure syndromes.
- In “transient ischaemic attacks”, there is transient impairment of cerebral blood flow.
- Transient ischaemic attacks include breath-holding attacks, "pallid" breath-holding attacks, fainting spells, cardiac arrhythmia and long QT syndrome, congenital heart block and ventricular tachycardias and migraines.
Description
The terms “fits”, “seizures” and “convulsions” are often used interchangeably when we describe episodic abnormal movements, stiffening of the body, or disturbed consciousness. These terms are more accurately defined by Brown and O’Regan (1998) as follows:
A fit is the clinical expression of an abnormal cerebral discharge – a dysrhythmia. It may be convulsive (stiffening or jerking) or non-convulsiv
e (as in absence or complex partial seizures).
A broader term is “seizure”. This is a paroxysmal alteration in behaviour due to various causes. These include:
- cerebral dysrhythmias
- anoxic or ischaemic attacks (faints)
- a large miscellaneous group often termed “funny turns”
A convulsion. This term should be used when a child has a sudden episode of stiffening (decerebrate posturing) followed by clonic jerking. Convulsions may be due to:
- Cerebral dysrhythmia (a true grand mal convulsion)
- Transient ischaemia
- Raised intracranial pressure
- Various toxins or drugs
Fits may be precipitated by sudden fever, infection, anoxia, various metabolic derangements, trauma and toxin ingestion. During infancy and early childhood recurrent fits usually reflect underlying structural brain lesions or one of several specific seizure syndromes.
Epilepsy is recurrent seizures with no demonstrable cause. It first manifests in most instances after the age of three years. Family histories of these children often provide evidence of a genetic influence.
Before applying the label “epileptic” to a child it is essential to eliminate other causes of recurrent “turns”.
Transient ischaemic attacks
A common and important group is the “transient ischaemic attacks”, where there is transient impairment of cerebral blood flow. This article will focus on these attacks.
1. Breath-holding attack
The breath-holding attack is a common and harmless spell, which has its highest frequency in the age range of one to three years. A tendency to breath-holding, however, may be shown at a much earlier age, even from the early days of life.
Breath-holding attacks are induced by minor injury or frustration. In the classical attack the child takes in breath to cry, lets out a single cry and then holds the breath in expiration. He or she is then unable to breathe in again because of glottic spasm, and no sound emerges. The child becomes progressively more suffused, the eyes turn up, and neck and back extend with pronation of the upper limbs. The heart slows markedly as cyanosis develops and it is this slowing which results in cerebral anoxia and loss of consciousness. This lasts only a few seconds, after which the child relaxes and begins to breathe normally. Very occasionally a clonic convulsion will follow.
There is a widely held misconception that the breath is held purposefully in inspiration; the episode is not induced voluntarily. Unlike true fits attacks are always precipitated by physical hurt or frustration.
Management of breath-holding attacks
An association with anaemia - particularly due to iron deficiency - is sometimes found, and there is improvement when this is corrected. However, drug treatment is seldom necessary. A full explanation emphasising the good prognosis and that there is no relationship to epilepsy is all that is required.
2. What then are “pallid” breath-holding attacks?
This term is a misnomer, because breath is not held during the spell as in the breath-holding attacks just mentioned. The modern term is “reflex anoxic seizures”. These are invariably induced by sudden pain or a fright.
The child gives a cry, and then abruptly loses consciousness. The face is ashen. Colour improves after ten to 15 seconds and consciousness returns. These spells are due to a pain-induced surge of vagal tone which slows the heart to a standstill for a few beats.
Management of “pallid” breath-holding attacks
Again, reassurance is usually all that is necessary. Attacks seldom recur after the age of four. Severe cases may be controlled with small oral doses of atropine.
3. Fainting spells
Fainting spells (vaso-vagal syncope) are uncommon in toddlers, but occur readily in school-age children who are unwell or made to stand for prolonged periods. There is a drop in systemic blood pressure which may be gradual or sudden. This causes a sensation of increasing malaise followed by loss of consciousness. The child sags to the ground and is noted to be very pale and clammy. The wrist pulse may be impalpable. Full consciousness returns after a few moments in the recumbent posture.
Management of fainting spells
The diagnosis can usually be made from the history, and the child and parents can be reassured that no treatment is necessary. The spell can sometimes be aborted by the child sitting down with the head between the legs. If spells are recurrent, full investigation by a cardiologist is advisable.
4. Cardiac arrhythmia and long QT syndrome
Sometimes sudden loss of consciousness – and even sudden death - may be due to a cardiac arrhythmia, and it is now known that this eventuality is commoner than was previously realised. Of special importance is the long QT syndrome. Due to a conduction defect in the heart the child is prone to bouts of ventricular fibrillation, induced often by exercise or stress. The condition may be hereditary, and one form is associated with congenital sensorineural deafness.
Management
Once diagnosed, attacks can be prevented with oral propranolol, 5-10 mg three times a day.
5. Congenital heart block and ventricular tachycardias
Occasionally congenital heart block and the ventricular tachycardias may also induce fainting spells.
In any child who has a seizure or “funny turn”, an ECG and the calculation of the QT interval corrected for heart rate, are mandatory.
6. Other cardiac conditions
Other cardiac conditions which may cause transient ischaemic attacks are listed here:
- Fallot’s tetralogy (infundibular spasm)
- Aortic stenosis
- Pericardial effusion
- Cardiac surgery
- Prolapsed mitral valves
- Atrial myxoma
- Ball valve thrombus
7. Migraine
Migraine is a common condition, affecting 5% of school-aged children, but it is rare below the age of two years.
The headache is due to dilatation of arteries outside the cranium. This is preceded by constriction – sometimes severe – of vessels within the skull.
Some young children with migraine experience sudden attacks of vertigo during which they will drop to the floor, or show other bizarre behaviour suggestive of epilepsy. These attacks are due to constriction of the basilar or adjacent arteries at the brain stem.
There is generally a strong family history of migraine, which is an aid to diagnosis.
Management
A range of measures and medications are available to prevent and alleviate attacks. Ideally the child should be managed at a migraine clinic.
(Written by Prof M. Kibel, Emeritus Professor of Child Health)
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