Thankyou Glenntaj for your comprehensive response. I will go through those links tomorrow when I am fresher, as I'm about to go to bed now.

I feel such a novice in all this and although I am very conversant with some other medical conditions this whole area is quite new to me....so lots of learning to do!

Also anyone........is a lumber puncture a worthwhile diagnostic tool.......or is it only useful for specific types of PN?