Sure, we can include internal existence as part of our definition of consciousness. But internal existence is thoughts, memories and emotion, not consciousness itself.

"let's say a person has an accident or illness which makes them loose all their senses of the external world (eyesight, hearing, smell, touch, pain, warm, cold...), but their other brain functions are intact. The still have all their memories, they are awake and feel, think, reason, form all the thoughts they could before. Would you consider such a person to be uncoscious?"

I would consider them to be conscious because they are aware of their thoughts, feelings and memories. You are creating a stawman argument there because that's not what I was referring to. If someone has lost all their external senses but still has their thoughts, memories and emotions, those are still THINGS that exist.

The situation I am referring to is if nothing existed at all - no memories, thoughts, or emotions. There would be no internal things to be conscious of. With nothing to be conscious of, there is no consciousness, since consciousness's very purpose is to be conscious of things.

It's like how an eye cannot see itself. And without anything to see, the sense of sight is useless. Without anything to be conscious of (including thoughts, memories and emotions), consciousness has no purpose. It ceases to have any meaning at all.