Flu. What are those viruses up to in there?

What the heck is it that the Flu virus does that causes so many different nasty and painful symptoms? I can picture runnng battles of virii vs antibodies raging in my bloodstream but that’s just a nice analogy surely, what’s really going on?

As a recent (and deep) flu sufferer I had quite a while to ponder this. So far my internet researchs haven’t turned up anything satisfying. How about the medical dopers, how does is it work?

Flu symptom check list:
Battery acid build up in lungs.
Cheap Scotch style hangover headache.
Baby elephants camping on chest.
Muscle aches as experienced by competitors at the end of a 72 hour endurace event
Overall fatigue equivalent to climbing in the Himalayan Death Zone, with no oxygen

I’m assuming that fun diversions like shivering fits and profuse sweating are just side shows laid on by the immune system trying to kick the virus’ butt.

And apart from the actual pain what naughty things is the virus actually doing to the body while you’re lying there suffering? If your immune systems eventually throws in the towel what will you die of?

The virus itself is just doing what all viruses do. Getting in cells, replicating, and killing the cells that it’s inside. What’s causing your suffering is, first, if your cells are being used to reproduce viruses, they can’t do what they’re supposed to do, and second, your immune system, in trying to kill off the virus, is causing all sorts of problems with your body’s regulatory measures, overproducing phlegm, causing a fever, etc.

If you die of the flu, what will you die of? You could die of the fever itself, you could die of the dehydration caused by the fever, or you could just die from the general strain all this is putting on your body.