Take a quick look at first of cases in hospital (4)
I believe the answer is:
scan
'take a quick look at' is the definition.
(I've seen this in another clue)
'first of cases in hospital' is the wordplay.
'first of cases' becomes 'c' (1st letter of 'cases').
'in' means one lot of letters goes inside another.
'hospital' becomes 'san' (I've seen this before).
'c' placed within 'san' is 'SCAN'.
(Other definitions for scan that I've seen before include "Take a quick look" , "Study the metre" , "Perusal" , "Glance at or read quickly" , "Peruse, scrutinise" .)