"diffuse thickening of gallbladder walls" ... stumped

my husband came to ER on monday with severe pain in side/gut ... has had the complete work up and now it is thursday and he's still in ... he had elevated white blood cell count when we came in ... his ultrasound showed diffuse thickening of gall bladder wall but the HIDA scan came back normal. we are concerned that they will try to discharge him as he has pain he cannot control without meds and will not be able to function at all ... what other tests can we request/are relevant to rule out cancer and other problems? any advice? any anomalies? need ideas! docs are not taking it seriously and tried to tell us it was "likely due to stress" which we KNOW is not the case! please help!