HI Thank for asking to HCM I really appreciate your concern, the bulky kidney is loos word being used, it could mean here, hydronephrosis, what I assumed from the history given here otherwise actual observing the image will clear the picture, hydronephrosis is condition where the urine accumulate in side the kidney this gives the impression like the size of kidney increased once the obstruction relieved then the size image comes to normal, hope this answer would satisfy you have nice day.