A seizure or fit is a sudden disturbance of nervous system function due to an abnormal nerve discharge in the brain.
The term convulsion is used when a child has a sudden episode of stiffening usually followed by jerking of the limbs and body.
Recurrent fits usually reflect underlying structural brain lesions or possibly one of several specific seizure syndromes.
In “transient ischaemic attacks”, there is temporary blockage of blood flow to the brain.
Transient ischaemic attacks include breath-holding attacks, "pallid" breath-holding attacks, fainting spells, cardiac arrhythmias such as the "long QT syndrome", congenital heart block and abnormal heart ventricle rhythms and migraine.
The terms “fits”, “seizures” and “convulsions” are often used interchangeably when we describe sudden episodes of abnormal movements, stiffening of the body, or disturbed consciousness. These terms are more accurately defined as follows:
A fit or seizure is the clinical expression of an abnormal cerebral discharge – a dysrhythmia. It may be convulsive (stiffening or jerking) or non-convulsive (as in absence or complex partial seizures).
The term “seizure” has largely replaced "fits" and is a paroxysmal alteration in behaviour due to various causes. These include:
Anoxic or ischaemic attacks (faints)
A large miscellaneous group often termed “funny turns”
"Convulsion": This term should be used when a child has a sudden episode of stiffening (decerebrate posturing) followed by jerking of the body and limbs. Convulsions may be due to:
Cerebral dysrhythmia (an epileptic convulsion)
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.
Epilepsyis recurrent seizures with no demonstrable cause. It first manifests in most instances after the age of three years. There is often a family history of epilepsy.
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 his or her breath when breathing out. He or she is then unable to breathe in again because of spasm of the muscles of the upper throat and no sound emerges. The child may develop a blue or deep red colour. The child’s arms may appear stiff. and neck and back are extended. The heart slows markedly as the child’s blue appearance colour deepens and it is this slowing which results in loss of consciousness. This lasts only a few seconds, after which the child relaxes and begins to breathe normally. Very rarely indeed a convulsion may occur.
There is a widely held misconception that the breath is held purposefully in inspiration but there is no voluntary aspect to these breath holding episodes. Unlike true fits, breath holding 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 child’s face usually appears extremely pale. The child’s colour improves after 10 to 15 seconds when consciousness returns. These spells are due to a pain-induced surge of the vagus nerve 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 episodes) are uncommon in toddlers, but occur commonly in school-age children who are ill or made to stand for prolonged periods. There is a sudden drop in blood pressure. This causes a sensation of sudden dizziness and weakness and is 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 difficult to feel. Full consciousness returns after a few moments once the child is lying down.
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 stopped if the child sits down with his/her 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 more common than was previously realised. Of special importance is the ‘long QT syndrome’. Due to a conduction defect in the electrical system of the heart the child is prone to bouts of abnormal electrical rhythms of the heart. This is often brought on by exercise or stress. This condition may be hereditary.
Once diagnosed, attacks can be prevented with a medicine known as Propranolol 5-10 mg three times a day.
5. Congenital heart block and ventricular tachycardias
Occasionally congenital heart block and abnormal rhythms of the heart ventricles may also induce fainting spells.
In any child who has a seizure or “funny turn”, besides having an EEG, an ECG and measurement of the QT interval is essential.
6. Other cardiac conditions
Other cardiac conditions which may cause transient ischaemic attacks are listed here:
Prolapsed mitral valves
Migraine is a common condition, affecting 5% of school-aged children, but it is rare below the age of two years.
Migraines cause a severe headache due to dilatation of arteries on the outside of the cranium. This is preceded by spasm and constriction of arteries inside the skull.
Some young children with migraine experience sudden attacks of dizziness during which they will fall down or may show unusual behaviour suggestive of epilepsy. These attacks are due to constriction of the basilar or adjacent arteries at the brain stem.
There is usually a strong family history of migraine, which is an aid to diagnosis.
A range of measures and medications are available to prevent and alleviate attacks. Ideally the child should be managed at a migraine clinic.
It is worthwhile trying a simple ‘migraine diet’ in which foods rich in the natural chemical tyramine found in certain foods, especially hard cheeses, are eliminated from the diet.
Reviewed by: Prof Eugene Weinberg, FCPaeds [SA}, FAAAAI, Paediatrics and Paediatric Allergology, Allergy Diagnostic Unit,UCT Lung Institute, September 2011