transient leukopenia changed to leukocytosis, is it a usual bone marrow response ?

I have a lady patient who underwent CT contrast (non ionic) for pain in abdo RIF( post appendectomy , 2yrs). She had an anaphylactic recation which was resolved immediately. her initial CBC showed Leukopenia (1000) and day 2 showed leukocytosis & shift to left ( 30,000). What coud be the reason for such a bone marrow repsonse? ( urine had a few RBCs initially).

She is stable clinically, NO Fever, NO LNpathy, NO HS megaly No icterus, Hb is normal. Platelets Normal. but pain in abdo ( RIF ) persists.