Inflammation: Cardinal Signs and Components

00:01 All right, there are five Cardinal Signs.

00:03 These are classic things, and you will see them.

00:05 And I'll give you both the Latin and the English.

00:07 I just like the Latin.

00:08 The Latin has a certain kind of, I don't know, erudition to it.

00:13 So I'm going to do that as well.

00:15 In the cardinal signs, Anytime, you mean, you've all been subject to.

00:20 You know, the cardinal signs of inflammation.

00:22 If you've twisted an ankle, you have a sprain, all of these things happen.

00:28 So the first thing that happens on the scene is Calor.

00:31 That is heat due to increased blood flow into the tissue.

00:35 Remember, I said there would be vascular dilation to improve blood flow.

00:39 So, it gets warm, it gets hot, it gets red, because we have increased blood flow and the vessels there are dilated.

00:45 So it's Calor and Rubor.

00:49 And then we have Tumor.

00:50 This is not cancer. This is just swelling.

00:52 That's all tumor means.

00:53 And so you have increased vascular permeability, that lets fluid get out into the tissue.

00:59 Good reasons for that happening.

01:01 But now you can imagine, your twisted sprained ankle, it's red, it's hot, and it's swollen.

01:08 Well, it also hurts like crazy.

01:10 So that's Dolor, the fourth cardinal sign.

01:14 And that pain actually is important because it helps us to recognize "Hmm, something happened.

01:18 Maybe I ought to take care of it or stay off it until it can heal." So there's a reason for pain.

01:24 And then finally, this one doesn't go with calor, rubor, tumor, dolor, but it's still adding.

01:29 So it's Functio laesa. It's the loss of function.

01:32 And that happens in the early settings of acute inflammation, and chronic inflammation.

01:36 And hopefully, we restore function.

01:39 But these are the five cardinal signs.

01:41 And what's shown below in the four panels is just the vascular changes the calor, and the rubor, and somewhat of the tumor that's going on in an area of inflammation.

01:52 This is an experimental model.

01:53 It gets redder, it gets hotter, and it gets swollen.

01:57 And I'm sure it hurt.

01:59 And I'm sure that functio was also not quite right there, too.

02:03 So anyway, we'll come back to the cardinal signs at the very end of all of this sequence, so that we can talk about the specific mediators that make all this happen.

02:12 Okay, there are components of inflammation.

02:14 We've drawn here, kind of a cartoon of the vessel wall.

02:17 And various cells and components of vessel wall.

02:20 So an inflammation endothelium, big player.

02:25 Very important in the overall process.

02:27 And we'll talk about how it does its job.

02:29 The surrounding smooth muscle around the vasculature also important because it will relax and allow the vessel to dilate, so that we get that rubor, and that calor.

02:41 And so the smooth muscle is also an important component.

02:44 The polymorphonuclear leukocyte, the PMN, the poly, the neutrophil is also critical in acute inflammation.

02:52 There are various mediators, and boy, are there a bunch of mediators.

02:57 We will talk about those in some excruciating detail, just because they are targets of therapeutic intervention, and you need to know about them.

03:06 So we'll come back to those.

03:08 There are also cells that live in the extravascular space, so outside of the blood vessel that are part of the inflammatory response.

03:14 And the mast cell is one of those.

03:17 This mast cell doesn't always get all the credit that it deserves.

03:21 But it's a cell that lives in the tissue.

03:23 And you can think of it as a sentinel.

03:24 It is out there waiting for something to happen.

03:28 and then it's got a whole bunch of granules.

03:30 So you can see the blue dots inside of the cell? It says, something has happened.

03:35 And we'll talk about how it recognizes that.

03:37 It releases those granules, and it starts the cascade of events.

03:41 So that's kind of, they're out there in the tissue in the guardhouse looking for the pathogens or looking for the damage, and they're going to start the sequence.

03:49 The other cell that's going to be important, especially for chronic inflammation is the macrophage.

03:54 And it started as a monocyte within the bloodstream, and once it crawled outside, now we're going to call it a macrophage, literally a big eater.

04:02 And it's going to be very important for the healing response.

04:07 Okay, mast cells have been very early.

04:09 They're the sentinels and saying, "Hey, something's going on. We got to take care of this." In the macrophages are relatively late.

04:16 Alright, so we're going to talk about endothelium.

04:20 For now, for acute inflammation, we're talking about the endothelial and smooth muscle cell responses that drive the early vascular changes, the rubor, and the calor, and the tumor.

04:31 And then we're going to look at the neutrophil and how it gets to where it needs to go, and what it does when it gets there.

04:36 And we're going to talk about some of those mediators.

04:40 So that's just a big overview of where we're headed.

04:43 This is exciting territory.

04:45 You're going to love acute inflammation.