Syncope Reflex asystolic syncope 2018-11-20T13:57:33Z true true https://www.ncbi.nlm.nih.gov/books/NBK2609/ Reflex anoxic seizures or reflex asystolic syncope occurs from early infancy onwards, either remitting pre-school age or evolving into vasovagal syncope. Alternative names include pallid breath holding and pallid syncope. In these events an unpleasant, typically sudden stimulus such as a bump, knock on the head, cut or abrasion leads to a profound vagal discharge with a dramatic drop in the heart rate and transient asystole. These events are not due to temper tantrums. The child may cry very briefly or let out a couple of grunts and then becomes exceedingly pale and loses consciousness. Decerebrate posturing with extensor stiffening may mimic a tonic seizure and be followed by flexor spasms and irregular tonic-clonic movements however the whole sequence of abnormal movements will just last a few seconds. Recovery of consciousness may be rapid but some children may sleep for hours after an event. The events appear very frightening for carers but have a good prognosis. When reflex anoxic seizures are very frequent, atropine or cardiac pacing may be considered. There is an uncommon situation in which an anoxic seizure may trigger a secondary prolonged tonic-clonic seizure; the anoxic-epileptic seizure. The two phases of the event can be distinguished by a careful history, as in most events individuals will have syncope without the epileptic component Reflex anoxic seizures A loss of consciousness followed by stiffening and brief clonic movements affecting some or all limbs, often misinterpreted as an epileptic seizure. Reflex anoxic seizure