Old, old Asian brought up a problem with fluid (6)
I believe the answer is:
oedema
'problem with fluid' is the definition.
(medical condition)
'old old asian brought up a' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'old asian' becomes 'mede' (inhabitant of ancient Media).
'brought up' is a reversal indicator (down clues only).
'mede' backwards is 'edem'.
'o'+'edem'+'a'='OEDEMA'
(Other definitions for oedema that I've seen before include "Condition of excess fluid in the tissues" , "Dropsy" , "Excess of fluid in bodily tissues" , "Tissue swelling from bodily fluid" , "Medical condition" .)