Pediatric Pulmonary Embolism (PE)

00:02 In this lecture, we’re going to discuss pulmonary diseases that show up in older children.

00:07 Now, we’re going to exclude cystic fibrosis, which has its own lecture, and we’re excluding pulmonary diseases that show up in infants, which also has its own lecture.

00:18 This is really other problems in children.

00:22 Let’s start off with pulmonary embolism.

00:26 So a pulmonary embolism can happen, but it’s very in children compared to adults.

00:34 It is seen more commonly in diseases or circumstances where there’s a predisposition to forming a clot and the mortality rate is only 20% that of adults.

00:48 In other words, children are more likely to have smaller pulmonary embolisms and they’re more likely to survive the event and live past it.

00:59 So in order to understand the pathophysiology of the pulmonary embolism, we have to recall Virchow’s Triad, the three things that are resulting in a clot inside a blood vessel.

01:11 One is stasis, one is the hypercoagulable state, and the other is endothelial damage.

01:18 And we have these three things, we’re at increased risk for creating a thrombus inside the child.

01:25 That thrombus can then proceed up and into the lungs, where it causes the pulmonary embolism.

01:32 One way to remember it is I's and O's.

01:35 So there are Is and Os that are responsible for causing pulmonary embolism.

01:40 The I's are indwelling central lines, prolonged immobilization, or inherited disorders of coagulation.

01:50 Remember, in kids, they present with unusual congenital problems more often than adults do, so these inherited disorders are something we will absolutely think of in a child who presents with a pulmonary embolism.

02:05 The O's: obesity, oral contraceptive pills, or orthopedic surgery, which is really more of the immobilization, but a nice way to remember that.

02:17 So in terms of the pathology of the disease, most pulmonary embolisms start as a thrombus in a vein, and then fly into the lungs.

02:27 This is usually starting off in a lower extremity but can be in the upper extremity, the pelvis, the kidney, or even just the right side of the heart.

02:36 And as we say it before, these are rare, but even rarer still are air emboli, tumor emboli, or fat emboli, which can cause similar symptoms, but aren’t necessarily from a clot.

02:50 So the pulmonary embolus, if it’s rare, how do we suspect it? These patients will typically have a history of sudden onset pleuritic chest pain.

03:03 They’ll have difficulty of breathing that is sudden onset.

03:07 About 50% of them will have a cough and about a third of them will have hemoptysis.

03:12 Hemoptysis in a child is never normal.

03:17 If they’re presenting with a massive pulmonary embolism, which is exceptionally rare and much rarer than in adults, these patients will have a sudden onset cyanosis and right ventricular failure.

03:31 These are the patients with jugular venous distention, hepatomegaly, they may have a single loud S2, other problems like that.

03:43 The majority of children presenting with a pulmonary embolism though are going to be non-massive PEs.

03:49 About half of these children will have tachypnea, they will often have tachycardia, and you may auscultate.

03:56 While you’re examining them, you may hear crackles, wheezing, or usually they’re just clear to auscultation.

04:05 So as you can see, a lot of these symptoms are somewhat nonspecific and in children it’s a rare condition, so you can imagine this is a challenging diagnosis to make, and it is.

04:17 One test that’s particularly helpful and important to know about is the D-dimer.

04:22 This is very important.

04:24 A positive D-dimer does not confirm a pulmonary embolism.

04:30 The D-dimer is an acute phase reactant that can be elevated by almost anything.

04:36 However, it’s almost unheard of to have a pulmonary embolism have a normal D-dimer.

04:43 So we routinely get the D-dimer as a way of ruling out pulmonary embolism.

04:48 If I have a patient with chest pain and tachypnea and I’m thinking maybe it’s a pulmonary embolism because the girl takes oral contraceptive pills, but I get a normal D-dimer, I usually won’t pursue this any further.

05:03 Other testing that’s important can be an ABG, which may show V/Q mismatch in the lung as a result of that clot.

05:11 A chest x-ray may show an area of collapse.

05:15 But, really, the most important test for truly ruling out a pulmonary embolism is the spiral CT.

05:22 Now, we do like to avoid radiation in children.

05:26 Remember, children are probably at more risk for cancer as a result of radiation exposure simply because there’s more mitosis going on and more opportunity for negatively impacting mitosis.

05:39 But the spiral CT is the way to go.

05:42 In the books, there will be mentions of V/Q scans; however, their accuracy at predicting pulmonary embolism is really no better than the spiral CT.

05:54 Also, you may read about angiography as the gold standard and this is absolutely true.

06:00 It is the gold standard, but really is very seldom used.

06:04 The reason being spiral CT is very good and angiography confers actually quite a bit of radiation.