Pathophysiology of Preeclampsia (Nursing)

00:01 So let's try to break down some of the physiology.

00:03 We've been talking around it. So let's dig in.

00:06 So there are three major things that contribute.

00:09 At least as much as we understand.

00:10 There are a lot of question marks that still exist around preeclampsia.

00:14 So immunologic factors, pre-existing risk factors, such as the ones we just talked about, and genetic factors can actually cause the placenta to develop abnormally.

00:25 So there's trophoblastic tissue inside the placenta that actually innervates its way into the uterine wall.

00:31 If that trophoblastic determination is actually shallow, so it doesn't make a deep formation, it can cause issues with perfusion.

00:39 So we think about perfusion and blood flow and the need for that blood flow to get to the fetus in order for it to grow.

00:46 If that is impaired in any way, the fetus will develop what we call intrauterine growth restriction.

00:53 So the fetus will be tiny.

00:55 Well, if you don't get enough food, and you don't get enough oxygen, it makes perfect sense that you would be tiny.

01:01 This happens during Stage 1. So that's 1st and 2nd trimester.

01:05 As we move out to 3rd trimester that abnormal placental development actually causes a lot of endothelial disruption.

01:13 So the body is saying, something is not right.

01:16 And it responds to that by releasing factors that cause vasospasm.

01:21 And also causes issues with coagulation, which brings us to the second half of what we're going to talk about.

01:29 Alright, so now, let's talk a little bit more about what's going on inside the vascular system.

01:36 So we have systemic vascular dysfunction.

01:39 So from that we have lots of vasospasm.

01:41 So think about the vessel like a straw, and it's just contracting.

01:46 And then from that we have damage and with that damage, we get capillary leakage.

01:51 From that capillary leakage, we have issues that present like sensitivity to angiotensin II, which is going to change our blood pressure, which gives us hypertension.

02:01 We have coagulopathies and abnormalities, and that's going to lead to the development of thrombocytopenia.

02:08 We can develop cerebral edema, and that may lead to eclampsia, depending on where the vasospasm is.

02:14 And once we have issues with our kidney system and our renal system, we can develop proteinuria, or glomerular endotheliosis.

02:25 I want to talk for a second about that vascular remodeling that goes on with the placenta.

02:30 So take a look at this graphic.

02:32 So during a normal pregnancy, and we think about the endometrium, we have spiral arteries that innovate into the uterine wall to help supply blood flow.

02:41 So normally, during pregnancy, the vessels are going to be opened up so we can increase the blood flow.

02:48 So this is what normal nonpregnant spiral arteries look like.

02:51 So go back and look at normal pregnancy, it's really wide.

02:55 Now, let's look at what happens with preeclampsia.

02:58 Do you see that? Do you see how that vasospasm has actually narrowed the blood flow? And so when we have constricted blood flow, then cytokines are produced, because that's telling the body, "Something's not right.

03:09 And I am upset, I am inflamed, And I'm going to further decrease blood flow." So now that we have that picture, let's see if we can put this together in terms of, how the client might present? So remember, all of these factors are related to vasospasm and decreased organ perfusion.

03:27 So when we have vasospasm, and decreased perfusion, all of the organs are going to be affected.

03:32 It doesn't just get to pick one or two.

03:34 It goes everywhere.

03:36 So let's think about the idea of hypertension and uteroplacental spasm.

03:41 Alright.

03:42 If we don't have good blood flow through the placenta, we're going to develop IUGR or Intrauterine Growth Restriction.

03:49 How are we going to notice that? We might notice that by measuring the fundal height and finding that the fundus is not growing.

03:56 The fundus is not growing, the fetus is not growing.

03:59 If we do an ultrasound, we may find that the fetus is actually lagging in growth.

04:03 So that may be one of the ways that we're able to pick that up.

04:07 If we have glomerular damage.

04:08 So thinking about the kidneys, we may have an increase in the plasma uric acid and creatinine levels, and the client might experience oliguria, which makes sense.

04:18 Poor perfusion to the kidneys means that we're not going to have as much output as we normally would.

04:24 If we have vasospasm in the cortical brainstem, then we're going to have a lot of neurologic symptoms.

04:29 So things like headaches, or hyperreflexia, or seizure activities.

04:36 So if we have spasm in the eyes.

04:38 so thinking of retinal arteriolar spasm, that's going to affect our vision.

04:43 The vision might be blurry, or the patient might complain of scotoma.

04:47 Now, they won't say, I have scotoma.

04:49 What they might say, is, "If I look at lights, I see a big circle around them.

04:53 So anytime I look up, or look at the ceiling lights, or anything like that, I see this really weird looking circle." That scotoma.

05:02 If we have vasospasm in the liver, then we're going to notice that because of labs.

05:07 We're going to find that they're elevated liver enzymes.

05:11 We also might notice a complaint. Nausea and vomiting.

05:14 Nausea and vomiting in pregnancy, not particularly unusual, New-onset nausea and vomiting, that's unusual, and should be a red flag to look for signs of preeclampsia.

05:24 The client may also complain of gap epigastric pain.

05:28 Now again, I've never really heard a client except a nursing student, maybe say, "I have epigastric pain." What they are going to come in and say is, "I have heartburn, and I just can't make it go away." Now, thinking of when preeclampsia occurs, as we're moving towards the end of second trimester, and into the third, heartburn is almost a normal symptom.

05:49 So we want to make sure that we don't ignore those symptoms that pop up and we always explore.

05:54 So thinking about upper right quadrant pain, epigastric pain, nausea and vomiting, and liver enzymes, all related to damage to the liver.

06:05 Now, when we think about intravascular coagulopathies, and we think of issues with clotting, other factors are going to start to appear.

06:12 We could have hemolysis of red blood cells.

06:15 So they're broken down.

06:16 We could have platelet adhesion, where they're clumping together.

06:20 We could have increased factor VII antigens, which again is going to cause issues with our clotting.

06:26 We can notice these symptoms because of low platelet count, or DIC, which is disseminated intravascular coagulopathy.

06:34 So this is where essentially, someone begins to bleed out.

06:37 So they may have petechiae, they may begin to bleed from an IV site or something like that.

06:42 We'll talk about that a little bit more later.

06:46 From the vasospasm, they may also experience increased permeability.

06:51 So what that means is, those are kind of holes that are formed in our vascular system, and the vessels become leaky and things begin to leak out.

06:59 So when we think about the effect on the renal system, one of those things that could leak out is protein.

07:04 So we may begin to see proteinuria.

07:06 Sometimes third spacing occurs, and the client may develop generalized edema.

07:11 So not just dependent edema, which can happen, but they may have edema in the face.

07:17 Sometimes, they get so much edema, they look like raccoons because their eyes are just squinted from all the pressure.

07:23 So the rings may not fit, or anything like that.

07:26 So think about upper extremity edema's as being a hallmark sign.

07:30 They may also develop pulmonary edema.

07:33 So think about it.

07:34 Anytime we have something that's happening with preeclampsia, it's going to be systemic. So no vessels are spared.

07:41 So the vessels in our lungs can also be affected and we may begin to collect fluid there or hemoconcentration.

07:46 So we may have changes in our H&H that are completely related to this increased permeability.

07:53 How does this present? Dyspnea.

07:56 If I have pulmonary edema, I'm going to have difficulty breathing.

07:59 And again, that increase hematocrit.