Syncopal attacks in children
20% of children will have a syncopal episode before the age of 15 years. More than 70% are due to neurally-mediated reflex responses and the vast majority are benign. Examples include Benign Vasovagal Syncope (simple faints) and Reflex Anoxic Seizures – probably better described as Reflex Asystolic Syncope. Both of these conditions are benign, but can be very upsetting for both the child and the parents. Careful history taking is the key to diagnosis.
Fear, sight of blood or other unpleasant stimuli typically provoke simple faints. Reflex Asystolic Syncope (RAS) is provoked by unexpected stimuli such as sudden noise or unexpected pain. The stimulus need not necessarily be strong – unexpectedness is the important aspect. Activation of the reflex causes the heart beat to pause for several seconds, resulting in loss of consciousness. Frequently the child will let out a cry just before collapsing. Limb stiffening and jerking are characteristic. Recovery is spontaneous.
RAS is not exclusive to children – it may also present in adulthood. Several people with this condition remain undiagnosed. Further information on RAS can be found at www.stars.org.uk.
Neurocardiogenic (vasovagal) syncope occurs in children as well as adults. As is adults, careful history taking often leads to the diagnosis. Tilt table testing, if required, may be used in children as young as 6 years old. Provocation should not be used. In the vast majority of cases all that is required is reassurance of the benign nature of Neurocardiogenic syncope, coupled with advice regarding adequate fluid and salt intake, and demonstration of physical manoeuvres used to abort attacks. See Non-drug treatment. If medication is required, low dose Fludrocortisone is often the best choice.
Epilepsy and psychogenic syncope account for about 20% of childhood syncope, and cardiac syncope about 6%.
Cardiac syncope can be dangerous. Warning bells should ring if there is a history of syncope during exercise, if syncope (without associated fitting) occurs when supine, or if syncope follows a sudden strong stimulus, such as a very loud noise. This last situation suggests that the child may have long QT syndrome. If cardiac syncope is suspected urgent referral to a paediatric cardiologist is warranted.