Why does a stress fracture cause swelling?

I suspect I have a stress fracture in my foot and have a doctor’s appointment scheduled. I’m wondering though, what is it exactly with stress fractures that causes swelling?

Simplistic version which isn’t totally wrong: The injury causes tissue damage, the tissue releases chemical factors which attract cells to help repair the damage, this draws in a lot of fluid also as the cells enter into the damaged tissue to begin to effect repairs, and the factors that the cells release to facilitate repair in turn cause more fluid and more cells to be drawn in.

Nothing **Qadgop **didn’t say, but using different words in case that helps: When the body is injured, chemicals are released by your broken cells. These chemicals trigger the body to send more fluid to the injury site. This fluid carries white blood cells and immune cells to identify and remove any bacteria or small foreign objects that might have gotten in through the injury. Platelets and other clotting factors come to stop any internal or external bleeding. It carries cells that eat up dead bone cells, and other cells that build new bone. As they do this, these cells themselves send signals to send more, like soldiers calling in reinforcements, and so even more fluid fills the space. All this extra fluid and stuff takes up space, which we see as swelling. A nice bonus: it makes the area stiff, acting as a natural split to help immobilize it. A not so nice: it also causes pain.

This is Inflammation. Inflammation has become a bogey-man lately, but it’s actually part of the normal healthy healing process.

Thanks. So sweling is a good thing here because it means it’s healing?

ETA I hadn’t seen WhyNot’s reply befor posting. Thank you to both of you.

Yes, but you should still get it checked out. The doctor will probably want to make sure all the bones are lined up and likely to stay lined up as it heels. The “natural splinting” of inflammation isn’t nearly as good as modern medical technology. Lots of our ancestors got some pretty funny looking legs and suffered a lot because their bones weren’t well aligned as they healed.

Yes, I’m definitely getting it checked out and I have visions of wearing a boot for the next six weeks. Damn New York City vacatios and all the walking and stair climbing involved.

So what happened? I’m in a similar spot!

The doctor poked at it and asked some questions, then said I could either get an MRI or wait a couple of weeks to see if it got better. I waited and it got better. I’d forgotten all about that.

Glad you’re better! Same experience I had–applied a “tincture of time” and all is good.