Infective Endocarditis (IE)

00:00 In this lecture, we're going to focus on acquired conditions of the heart.

00:05 Specifically, we're going to look at endocarditis, myocarditis, causes of cardiomyopathy, and also pericarditis.

00:15 Let's start with infective endocarditis.

00:20 Infective endocarditis is quite rare in children.

00:23 It's more common in infants who've had catheters, or in adolescents who were using IV drugs.

00:30 But we see it rarely, maybe 1 in 300,000 people.

00:33 But despite of it being rare, it is dangerous and it does confer about an 11 percent mortality rate in children.

00:42 The incidence in the United States in children is increasing likely through more children going through NICUs and through increased use of IV drugs.

00:54 Let's look at the bacteria that are most likely to cause endocarditis and specifically focus on how the bacteria relate to the presentation of the patient.

01:05 One of the most common causes of bacteria causing endocarditis in children is Staphylococcus aureus - we'll call it "Staph aureus".

01:13 Staph aureus is a very aggressive ogranism.

01:16 It can cause acutely very ill children and can also cause abscess formation within the context of the inside of the heart.

01:24 Coagulase-negative Staph is more subacute - results in chronic fevers.

01:32 Alpha-hemolytic Strep can also cause endocarditis - and again, that's more a subacute condition with chronic fevers.

01:40 Gram-negative rods can rarely cause endocarditis.

01:44 Those patients will have subacute illness and chronic fevers, but also may be more likely to develop embolic disease, clots forming as the blood flicks out of the heart.

01:55 Fungal endocarditis is very severe and these infants will present usually with very acute illness and they have a very high mortality rate.

02:06 When you're seeing a patient with endocarditis, there would be a few key points to their history.

02:14 Often, they will have diffused myalgias.

02:16 They may have fatigue.

02:20 They'll have arthralgias or sore joints.

02:23 But key is they'll have fever, and this is in you differential for a child with fever of unknown origin.

02:31 On exam, there are many key findings that are pretty high-yield or likely to show up on an exam.

02:39 They may have a toxic appearance.

02:41 They may have a new onset heart murmur, though they don't have to.

02:45 You'll notice neurologic symptoms if they have a left-sided endocarditis, which is common among endocarditis, and those bacteria could be flicking off systematically and getting into the brain resulting in abnormal mentation, stroke, brain abscesses, meningitis.

03:07 You may see Osler nodes on their exam - and we'll talk about what those are in a second - you may see Janeway lesions, and you may see splinter hemorrhages.

03:18 And last, you may see Roth spots.

03:21 I'm going to go through these four physical exam findings carefully.

03:26 First, Osler nodes. Osler nodes are found usually on the extremities.

03:31 They are small, tender, raised nodules.

03:35 They're usually on the pads of the fingers and toes. These are rare.

03:41 I have personally never seen an Osler node, but they love asking about them on test questions.

03:47 Janeway lesions are also rare. These are flat, red lesions.

03:53 They're found on the palms and soles.

03:55 In this patient on this slide, you can see them right there on their fingers.

03:59 These are painless unlike the Osler nodes, which are a little bit tender.

04:04 Also, these patients may have splinter hemorrhages on their nails.

04:09 Last is Roth spots. These are on the ophthalmologic exam.

04:13 On fundoscopy, you can see these little lesions in there that are in the retina.

04:19 These are retinal hemorrhages as a result of clots landing in the retinal artery in that capillary bed.

04:27 You'll notice, especially with the one with the white arrow, that there's a pale center, and that's what's key in a Roth spot.

04:36 If you see something in a patient regarding their history or their physical exam and you suspect endocarditis, what's key is a large volume blood culture.

04:46 This is a blood culture of between 5 and 15 milliliters of blood.

04:51 It's a huge amount of blood obtained for blood culture.

04:55 Small volume blood cultures are suboptimal.

04:59 These large volume blood cultures will be positive in more than 90 percent of cases.

05:04 Often, if we suspect it, we may obtain multiple large volume blood cultures on subsequent days to make the diagnosis.

05:13 A cardiac echo is indicated to look for a lesion that may be growing on one of those valves.

05:20 But remember, false positives and false negatives on endocarditis on the echo are common.

05:27 Frequently, the echo will be normal in a patient with endocarditis.

05:34 How do we treat endocarditis? Antibiotics are key.

05:38 Generally, you're going to treat the organism that grows on the culture.

05:42 If you strongly suspect endocarditis but don't have the identity of the organism, remember that everyday this child has bacteria growing on his or her valve is a day of valvular destruction, which can result in great pathology down the road.

06:00 So initial therapy should be broad coverage and aggressive.

06:06 We'll often give this children vancomycin and ceftriaxone, and maybe add in amphotericin if we suspect a fungal agent, especially in the critically ill children.

06:18 The therapy is going to be prolonged and will usually require a PICC line placement and a very prolonged six to eight weeks of IV antibiotics.

06:28 In patients who have a history of endocarditis, we may put them on prophylaxis.

06:35 If they have a history of endocarditis, they'll be on antibiotics every day to prevent a reinfection.

06:40 They may also need prophylaxis of the prosthetic valves, or if they are a heart transplant.