Anxiety can build gradually and is usually linked to an event, situation, or experience that's perceived as threatening or stressful. Panic attacks, however, often occur out of the blue and aren't always cued by stressors.
This book may give you:
Stop Panic Attacks At Night: How To Help Your Child Overcome Panic Attacks How To Stop Panic Attacks Forever: Deal With Child Panic Attacks Overcome Anxiety: Panic Attack Symptoms