When I watched this as a kid I immediately thought the fever came on because of Zuko's inner battle/turmoil came into a culmination.
I read some posts and comments talking about this, most people see it that way too.
But, now as an adult I've started to gain a new perspective. That maybe we just added some additional layers into this scene, because that's how we wanted to view it. In either case, that part doesn't really matter, we each choose for ourselves the story we want to see.
Without getting too much off topic. This notion, that I've had as younger, but now focused more on as an adult.
Maybe Zuko was already sick and with fever; his rage and "never giving up", all the pain inside him just kept him going, even when he was ready fall on the ground.
Now that he's finally let go of all of that, he collapses to the ground.
Both interpretations work in this scene, there could be more ways to interpret, so please tell me if you have them. But, the latter one I talked about imo adds a lot more emotional weight to the situation; than just Zuko feeling the physical effects of his inner battle.
But, one doesn't need to exclude the other. Tell me how do you view this scene?
Is it Zuko letting go of rage and feeling effects of ongoing fever, or is it something more? Something spiritual?