mrcpsych-1436

A 3-year-old girl wakes up crying in the middle of the night. This typically occurs shortly after she has fallen asleep. Her parents report that she sits up in bed and appears to be awake but does not acknowledge them. The episodes last for a few minutes before the child falls back asleep. The parents have checked her pulse during these episodes and note that it is very rapid. This started happening around six months ago and lasted for about two weeks before resolving on its own. What is the likely diagnosis?