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Introduction
Reflex anoxic seizures (RAS) are a well-recognised but still underdiagnosed entity, which must be considered in the differential diagnosis of non-epileptic paroxysmal events in infants and preschool-aged children. Other terminology for RAS includes 'reflex asystolic syncope', 'pallid or white breath-holding spells/attacks', 'infantile vasovagal syncope' and 'pallid syncopal attacks'. Older children and adults with the same disorder have been diagnosed with 'convulsive cardioinhibitory neurally mediated syncope'. 1 Reflex asystolic syncope would seem to be the most appropriate alternative term because it describes precisely what occurs in this clinical entity; it also avoids using the word 'seizure' that increases the potential to misdiagnose RAS as epilepsy.
Classically, RAS are provoked by a sudden and typically distressing stimulus (injury, shock, fright), which causes an acute loss of consciousness. This is characteristically preceded by the child crying out, either immediately following or after a few seconds delay following the stimulus. The child will then become pale and floppy. This is then followed by opisthotonic stiffening, cyanosis and few brief myoclonic or clonic movements affecting some or all four limbs. It is this phase that is commonly misinterpreted as representing a generalised tonic-clonic seizure, thereby labelling the child as having experienced an epileptic seizure. The underlying pathophysiology is a vagal-induced brief cardiac asystole with resultant cerebral hypoperfusion and consequent anoxia. Despite their brief and benign nature, parents, carers and teachers who witness RAS may be understandably anxious and consider that their child has either stopped breathing or is having a 'fit'. Many will pick their child up or attempt cardiopulmonary resuscitation, or both. The crucial components of the management are to ensure the diagnosis of RAS is correct, and specifically, that there is no underlying cardiac arrhythmia, reassurance (of the child's parents but also the extended family and teachers) and the avoidance of unnecessary investigations, including an EEG, which may in fact induce an episode in particularly susceptible children. This review focuses on the management of RAS in young children and appraises the literature on this condition.
Definitions
Syncope is a transient, self-terminating loss of consciousness with rapid onset, short duration and spontaneous complete recovery. 2 Global cerebral hypoperfusion is the underlying mechanism behind any syncope. Reflex syncope typically occurs following a specific trigger that activates the sympathetic or...