Chapter 1: What is the main topic discussed in this episode?
Welcome back, Clinical Problem Solvers. Maddie and Yusuf here. At CP Solvers, our mission is to make clinical reasoning accessible to learners worldwide. We invite you to join us for our live virtual morning reports, where we break down cases and sharpen our diagnostic reasoning together. Now over to you, Yusuf.
Thanks, Maddy. Just a quick reminder, this podcast is for educational purposes only and is not a substitute for medical advice. Patient details have been modified to protect their privacy and the views expressed here are our own, not those of our employers. Now, let's dive into the case.
Enjoy the show.
Hello, everyone. Welcome back to another episode on the Schema series. We have some clinical problem solvers here. I'm Mark, a hospitalist here at Stanford, and I have my great crew, my great Schema crew. How are you doing, Maddie?
I'm doing great. Great to see you all. I'm super excited to present this case to you all. I have just about two to three weeks left of maternity leave, so kind of soaking in this time at home before jumping back to the wards. What about you, Noah? How are you doing?
Hey, everyone. I'm doing pretty good. Yesterday was my partner's first day at her new job. So I'm excited to kind of, I'm waiting for her to get home so she can tell me everything that happened and all that. So excited for that. What about you, Yusuf?
Yeah. Hi everyone. I'm good. I was just telling Noah that I'm getting physical therapy done for ACL surgery that I had. And I love physical therapy. It's like a workout. It's a positive relationship. You check the weights, you get stronger, you get better. And I now can confidently prescribe it to my patients and know that it's like a positive experience. So it's my PT journey.
Yeah. I feel like I've referred so many patients to PT, but I personally have not experienced it.
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Chapter 2: What is pulmonary hypertension and how is it diagnosed?
So glad to hear that. It's such a great thing.
Yeah, bring PTOT to VMR.
Yeah, exactly. Okay, guys. Well, I am so excited to present this case to you all. So I'm just going to jump right in. So this is a case I saw on my ICU rotation a few months ago. And basically, you know, you get called to come evaluate a patient in the emergency department. And the first pieces of information I hear is that this is a 79 year old woman.
And she was sent to the emergency department actually from an outpatient pulmonary hypertension clinic. So she presented to the outpatient pulmonary hypertension clinic for basically a new patient evaluation. She was there to establish care.
But before she even had her appointment, she was using the restroom and a rapid response was called when she was in the restroom for basically shortness of breath and a syncopal episode. So this rapid response was called. And so before she could even have this appointment, she was transferred to the emergency department for further workup. So Noah, maybe I'll pass the mic to you.
Of course, you don't know too much information at this point. But, you know, with these two things, like pulmonary hypertension clinic, syncope, how could those two things be related? And what's crossing your mind?
You know, that's a great introduction to the case. And I have learned this factoid during my ICU rotation that patients with pulmonary hypertension, they have to avoid doing Valsalva. And the reason behind it is kind of the same reasoning why we are so hesitant in using positive pressure to ventilate those patients.
which is to increase their anthrothoracic pressure and then kind of reduce their preload. And they're very preload state dependent with the pulmonary hypertension and the likely right-sided heart failure. So it's very good that she... valsalva and syncope in the clinic where there are people able to help her. And I'm very worried because to me, that's a marker of pretty advanced disease.
Of course, we have to do our due diligence and kind of exonerate other causes of syncope. But I think for me, that would be a Pretty convincing story for severe pulmonary hypertension causing syncope with increased intrathoracic pressure. What do you think so far, Mark?
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Chapter 3: What are the common symptoms and history of a patient with pulmonary hypertension?
And maybe we can dive into how you all think about the causes.
Absolutely. And great aliquot, Maddy. And hearing things out loud, I'm still trying to label the problem. And we heard about a possible diagnosis of pulmonary hypertension. We heard about lower extremity edema. And then we heard a lot about cardiometabolic risk factors.
In general, when I heard about the lower extremity edema, the thing that came up to my mind is this is an evidence of right-sided disease, so right-sided heart disease. And I would be hesitant to label this just heart failure. Instead, I would label it specifically as right-sided disease because we only heard about edema so far.
We didn't hear about pulmonary edema, only some in the lower extremities. And then that makes the pulmonary artery potentially the center of attention of the case here. The patient is at risk for HFPAF. And what is HFPAF? So it's heart failure with preserved ejection fraction. And
We used to think in the past that high blood pressure causes LV hypertrophy and that alone causes HFPF, but now we think of it as a cardiometabolic disease that occurs in females who are older than 70 with risk factors such as AFib, higher BMI, diabetes, and hypertension, etc.
But the fact that we don't hear about any left-sided symptoms is making me think, is the pulmonary artery the center of attention of the case? And before I talk about the etiologies, Noah, I would love to hear about how you think about the anatomy of pulmonary arterial disease, and do you have an approach? And I know you love to take us through the journey of blood vessels, et cetera.
I know you did it last time for our episode.
Actually, Yusef, I don't think about pulmonary hypertension in an anatomical way. I have a much more pragmatic approach of pulmonary hypertension because I have found that, we'll talk about this in further other quotes, but the way we classify pulmonary hypertension is in the WHO groups, so group one through five, and that's kind of based... based on mechanisms and etiologies.
And then on the right hard calf, you classify it based if it's pre-capillary, if it's combined pre and post, or if it's post-capillary. But all of them are kind of not very intuitive to me because you can have group one having the same right heart calf as group two and group three and so forth. So there's kind of like a lot of mixed data. So that's not the way I approach it.
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Chapter 4: How do right heart catheterization findings indicate pulmonary hypertension?
Lung disease like COPD is really common. pulmonary embolisms are really common, right? So I think it's really easy to say, oh, this patient has pulmonary hypertension from their HFPEP. The patient has pulmonary hypertension from their COPD. Oh, they had a prior PE, maybe they have CTEF and kind of stop the workout, work up there.
And I've had, I've seen patients get misdiagnosed with group, you know, group two, group three, and wind up having group one PAH and really not be started on therapy. Um, or start on therapy much later in their course than they should have and kind of suffered some consequences, unfortunately.
So I think it's very important to be like, okay, if we're saying this patient is group two, let's say, is their HFPEF that severe to lead to this severe pulmonary hypertension? Is there CPD or, you know, hypoxemia? Like, in proportion to the degree of their pulmonary hypertension?
Those questions aren't always easy to answer, but I think it's something you have to think about before you label someone as group two or group three. Again, because these diagnoses are just so, so common. I think the one thing that stuck out to me, I'm like, whoa, why is this patient on five liters at baseline? What is going on there?
Maddie put in our chat that this patient has a BMI of 26, but we don't have really a past medical history of chronic lung disease. But obviously, chronic hypoxemia certainly can lead to pulmonary hypertension. And we need to explain why this patient is on five liters of oxygen.
Like I need a high resolution CT chest immediately to see if this patient has interstitial lung disease or just, you know, know what is going on with their lungs that's beginning to be, you know, chronically hypoxemic at five liters. I think the one other misnomer too is pulmonary hypertension does not or rarely leads to hypoxemia, right?
Hypoxemia can result in pulmonary hypertension, but the reverse is not possible. is not commonly seen, right? Pulmonary hypertension like PEs is more of a hemodynamic disease, right? When pulmonary hypertension gets severe, the RV starts failing, people get cardiogenic shock before they really get hypoxemia. I've seen patients like, oh,
patient with pulmonary hypertension comes to the hospital with hypoxemia. Oh, it's probably just from the pulmonary hypertension. That is not true. It's a very late stage finding. And what I was taught by one of my ICU residents, my intern years, that the mechanism really is a low mixed venous oxygen saturation.
So what that means is that when the pulmonary hypertension gets so, so severe, the lungs just try to extract, extract as much oxygen as they can, because you're not getting a lot of blood flow through the capillaries. And that leads to a low mixed venous sat on the other side. And that can eventually lead to hypoxemia. Again, that is a very, very late stage finding.
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Chapter 5: What are the WHO classification groups for pulmonary hypertension?
Her respiratory rate was 16. And when I went to go see her, she was on her baseline of 5 liters per And I'll kind of comment on those five leaders. It was also kind of interesting to us because initially when looking through the chart, it was not clear what that was secondary to. So that was also kind of a question mark in our mind. So on physical exam,
She was most notable as she had, um, jugular venous distension to her earlobe. She had, um, lower extremity pitting edema, even like past her knees, like up into her thighs. Um, her belly was generally soft, non-tender, um, non-distended. Uh, she was sitting in bed able to, um, answer questions there with her son. Um,
And was not in like significant kind of respiratory distress when I went to go see her. And actually when listening to her lungs, there were no obvious abnormal breath sounds. Like no obvious crackles, no rails that I heard. And kind of no obvious rashes on extremity exam. So for her WABS, her CBC was unremarkable. Her BNP, most notable for a creatinine of 2.27 from a baseline of 1.4.
Her BNP was 5,000. And her lactate, the first one was 7.8. TSH was normal. I'll give you a little bit more work up here. So chest x-ray on admission commented on a small left pleural effusion and enlarged cardiomediastinal silhouette.
And then looking kind of past in her chart, she had a CTPE one month prior at that earlier admission that actually showed a normal appearing lung parenchyma and no pulmonary embolisms. And she had a transthoracic echocardiogram also during that last admission that had an EF of 55%.
It commented on the right ventricle being enlarged, the RV systolic function was reduced, the right atrium was enlarged, and had ventricular septal flattening consistent with RV pressure or volume overload. It also commented on severe tricuspid regurgitation on that echo. On that TTE, there was an estimated PA systolic pressure of 71.
Also kind of digging through her chart, I see that she had pulmonary function testing three months before this admission that had normal spirometry, but an isolated low DLCO. So ultimately she was admitted, she was started on IV diuresis. and we held her sildenafil, given the concern that it may have been worsening her symptoms.
I can tell you a little bit more about, maybe I'll pause there, and then I can comment a little bit on some of the serologic testing that had previously been done into her pulmonary hypertension. Mark, that was a lot of data, but I'm going to pass the mic to you just to hear your general thoughts, and then maybe we can pass the mic to Yusuf to give an overview of the WHO classes.
Awesome. Yeah, this is a really rich aliquot, Maddy. But I took a deep breath and there's definitely a sigh of relief when I see these vital signs. Anytime I'm like I was admitting a patient with pulmonary hypertension, that seems a little tenuous. Like I get I get worried they're going to be hypotensive. You know, these patients can crash really quickly, like I said, with that RV death spiral.
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Chapter 6: What is the significance of elevated pulmonary artery pressures?
The BMP, again, the creatinine, not overly surprising. They have an AKI, a creatinine of 2.27 from their baseline of 1.4. Really, the most common reason that a patient would volume overload, this could be from left heart failure, this could be from right heart failure. The most common reason they would have an AKI on admission is cardiorenal syndrome, right?
This patient's pulmonary pressure is presumably extremely high and are essentially just strangling the renal vein, right? So that perfusion pressure to the kidney is severely reduced. So you're going to get an AKI. And usually with diuresis, they just get better, right? But in someone like this, I know the numbers look okay, but you can have normotensive cardiogenic shock, right?
And that's something you have to think about every time you have a patient with severe pulmonary hypertension is like, is this patient tipping into cardiogenic shock? So if that creatine doesn't get better, with diuresis. If this patient starts to have cool extremities and narrow pulse pressure, we're going to have to think about early inotropic support for this patient too.
And that really, you know, that kind of blends well with the lactate, right? So Maddie said this lactate was 7.8 and improved to 3.2 at diuresis. I'll say going back to the law of proportionality, this lactate 7.8 is way out of proportion to this patient's hemodynamics. Even if they have a normotensive cardiogenic shock, There is no way that is solely driving a lactate of 7.8.
A lactate of 7.8, if you guys just, you know, seeing a lot of lactates are in residency, like that's like a lactate sometimes you get when a patient's like during a code, like, you know, it's extremely high lactate. But, you know, it's important to remember not all lactic acidosis is from hyperperfusion, right? There's kind of type A and type B. Type A is kind of perfusion-related.
It's the most common reason we see an elevated lactate. And it's any of your causes of shock can cause a type A lactic acidosis. One thing I can see missed sometimes is that you can have systemic hyperperfusion, like I mentioned, from sepsis or cardiogenic shock. But then you want to think about local hyperperfusion can also lead to an elevated lactate.
And sometimes we see that with mesoteric ischemia or compartment syndrome. So it's not just global. It can be from localized. But we're not really getting a flavor of anything you know, global systemic hyperperfusion or local that would lead to this degree of lactic elevation. So I kind of have my antennas up for type B lactic acidosis, which has a lot of mechanisms.
The thing I'll bring up here is that is something called the Warburg effect that you can see with cancers. And the reason I bring that up is that, you know, this patient had a widened cardiac silhouette. Now, that could just because their pulmonary trunk is huge, right? But, you know, there's
this patient could have some sort of mediastinal mass, like the terrible T's, like lymphoma or all the other causes of an anterior immunocidal mass. And I would say the forgotten category of pulmonary hypertension is group four, which we think about CTEP, but it's really anything that causes pulmonary artery obstruction. And that could be external or internal.
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