Urgent, filth is back on hospital department (8)
I believe the answer is:
strident
'urgent' is the definition.
(I've seen this before)
'filth is back on hospital department' is the wordplay.
'filth' becomes 'dirts'.
'is back' says the letters should be written in reverse (I've seen 'be back' mean this).
'on' is a charade indicator (letters next to each other).
'hospital department' becomes 'ENT' (abbreviation for Ear, Nose and Throat department).
'dirts' backwards is 'strid'.
'strid'+'ent'='STRIDENT'
(Other definitions for strident that I've seen before include "Harsh in tone" , "Unpleasantly rough" , "Loudly assertive" , "Offensively loud and harsh" , "making loud noises" .)