Coughing up blood doesn't make sense for 99% of injuries and illnesses in fiction but it's HOT and I think the sexiness of whump outweighs the medical accuracy most of the time. I WILL die on this hill and I will be coughing up blood as I do so.
It's a great shorthand for the audience that this injury/illness is serious and will lead to death. Even though very few people alive have watched someone succumb to tuberculosis.


























