Karen Adams is a woman who had Wegener's disease who was ultimately killed by her husband in what he claimed was a mercy killing.
Karen came into the practice enraged after her husband told her he wanted a divorce. She blamed Violet for planting the idea in his mind. During the confrontation, Karen had a nosebleed, so Sam took her into a room to cauterize it. Doug later came back after speaking with Violet resolute in his decision to ask for a divorce, but hesitated when he saw that the bleeding had worsened. Sam believed that she had Wegener's disease, which would ultimately be fatal. He went to run tests to confirm, but learned that Karen had already been diagnosed at St. Ambrose Hospital six months prior. Despite this, Doug decided to stay with Karen, saying it's what he wanted. ("In Which Addison Finds the Magic")
Karen was later shot to death by her husband. He initially claimed that it was a mercy killing and she asked him to do it, but later confessed that he had shot her in cold blood. ("Crime and Punishment")
She was married to Doug Adams for 19 years when he told her he wanted a divorce. She constantly belittled him and tried to guilt him into staying with her, especially after he found out she had Wegener's disease. ("In Which Addison Finds the Magic")
He later murdered her after enduring months of her throwing things at him and calling him an idiot. ("Crime and Punishment")