How Can Swelling In The Throat And Difficulty In Swallowing Be Treated?

My mother in-law was admitted to an English hospital three days ago. She is 87 and is (was) quite healthy, taking no pills or medication. She suddenly started having her throat swell up. Currently she can barely swallow liquids, let alone food. She cannot move her head from side to side or up or down without severe pain. She has elevated white blood cell count. Been given oral morphine with little help. (I think they are trying other pain meds). She has had MRI and CT scans that are inconclusive. She has been antibiotics with no noticeable improvement.The doctors are at a loss.