Did a quick Google search on medieval medicine last night and maggots were a common thing back then for treatment. Still used today in some places, maggot therapy is the name
There's a lot of fan theories on why the Mad King went mad but maybe he got an untreated prick from the throneThere's a superstition/folklore in the books with the throne cutting kings unworthy of it too. If its cutting you it's because you don't belong there something like that. I think a king actually dies from the chair at some point before this too (there was a Targ king who was a real POS who was fukking everything up that went out from a chair cut).