What encephalopathy unspecified means in a child 4 years old?

Cause unknown: There are a multitude of events/agents that can result in brain injury.These can occur during pregnancy or later but not be recognised until a kid begins to miss expected developmental milestones. In the early 80's it became apparent that more than half of kids with CP, a marker for brain injury had no known pregnancy problem.Encephalo=brain,pathy=injury,unspecified