Jargon

I've learned a new jargon today:

Myalgic encephalomyelitis

Sounds fancy?

What it actually means is chronic fatigue syndrome.
myalgic = muscles pain
encephalo = brain
myelitis = inflammation

Presenting symptoms of myalgic encehalomyelitis are fatigue, muscle pain and mental fogginess. Symptoms can not be explained by other conditions such as depression and malignancy. In other words, causes unknown. Could be a combination of different factors.

Why do we need such hard-to-spell word to describe something that's not-so-hard to understand? O___o