Treatment Choices in Infective Endocarditis Prophylaxis

A 72-year-old with a prosthetic aortic valve presents stating, "I was told I have to take a medicine before I have a deep dental cleaning." Concurrent health issues include hypertension, type 2 diabetes, and dyslipidemia, currently at treatment goals. Medications include metformin, hydrochlorothiazide, telmisartan, and rosuvastatin. She has no drug allergies. Which of the following is the most appropriate next step in her care?

A. amoxicillin 2 grams PO 30 to 60 minutes prior to the procedure

B. amoxicillin 2 grams PO 1 to 2 hours after the procedure

C. cephalexin 2 grams PO 30 to 60 minutes prior to the procedure

D. inform the patient that no antimicrobial prophylaxis is needed during dental care. 

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Transcript

Voiceover: Welcome to NP Certification Q&A presented by Fitzgerald Health Education Associates. This podcast is for NP students studying to pass their NP certification exam. Getting to the correct test answers means breaking down the exam questions themselves. Leading NP expert Dr. Margaret Fitzgerald shares her knowledge and experience to help you dissect the anatomy of a test question so you can better understand how to arrive at the correct test answer. So, if you're ready, let's jump right in.

Margeret Fitzgerald: A 72-year-old with a prosthetic aortic valve presents stating, “ I was told I have to take a medicine before I have a deep dental cleaning.” Concurrent health issues include hypertension, type 2 diabetes and dyslipidemia currently at treatment goals. Medications include metformin, hydrochlorothiazide, telmisartan and rosuvastatin. She has no drug allergies. Which of the following is the most appropriate next step in her care?  

A. Amoxicillin 2 grams PO 30 to 60 minutes prior to the procedure

B. Amoxicillin 2 grams PO 1 to 2 hours after the procedure

C. Cephalexin 2 grams PO 30 to 60 minutes prior to the procedure

D. Inform the patient that no antimicrobial prophylaxis is needed during dental care

The correct answer is A. Amoxicillin 2 grams PO 30 to 60 minutes prior to the procedure. 

Where should we start with this question? Well, first let's determine what kind of a question it is and given that we are asked about prescribing this is a plan/intervention question. First, some background information. Antimicrobial prophylaxis prior to dental and select other procedures is recommended for a group of individuals with risk conditions in order to help prevent infectious endocarditis. And infectious endocarditis, if you'll remember, is an infection of the lining of the heart, the endocardium. It's often abbreviated IE. 

IE risk factors include select cardiac conditions including prosthetic cardiac valve which is what we have with this patient or prosthetic material used for cardiac valve repair select congenital heart defects both repaired and unrepaired and certain other conditions such as cardiac transplantation. I'm going to refer you to the AHA IE prophylaxis guidelines for details on the recommendations in congenital heart disease and transplantation because there's really significant inclusion exclusion criteria with these situations.

Another significant risk is injection drug use that increases the IE risk about a hundredfold over the general population. A history of infectious endocarditis regardless of the cause also dramatically increases the risk of future episodes and IE prophylaxis is indicated. And you might be thinking great I need to learn then all these inclusion exclusion criteria. I'm going to roll out a comment that I've only said about a million times over teaching review and in these podcasts. Common conditions occur commonly. The NP boards particularly primary care like family and adult-gero primary care test the common not the esoteric. Therefore, if you have an IE prophylaxis question on your boards, it most likely will be focused on prosthetic valves or prior IE history, which in the general public are the two most common reasons to require infectious endocarditis prophylaxis. And when it is indicated IE prophylaxis is recommended with dental procedures that involve manipulation of the gingival tissue. dental periapical regions or perforation of the oral mucosa. 

How can IE present? Well, it can develop either slowly or rapidly depending on the causative pathogen. And signs and symptoms include fatigue, fever, night sweats, involuntary weight loss, and a new heart murmur. The type of murmur generally reflects which heart valve or valves are infected or involved in the IE disease. In other words, if the aortic valve is involved, then the resulting change in the cardiac exam would most likely be the murmur of mitral regurg. The mitral valve was involved, it would also most likely be the murmur of mitral regurg. I also have another podcast that goes into who qualifies for infectious endocarditis prophylaxis.

Now, here's something that you might have noticed in clinical practice, or you might have just heard among family members, friends or something like that. Years back, more patients qualified for IE prophylaxis. However, over the past decade, in fact, it might be two decades now, who gets infectious endocarditis prophylaxis backed by best evidence is much shorter list in far fewer people. Here's the other part. Even in the higher infectious endocarditis risk patients, if endocarditis does occur, it has been noted through best evidence that it usually is a result of a minor cut or nicks from daily living that provides the portal to infection. It is not a dental procedure or other procedure. And if you're saying, "What the heck do you mean by cuts and nicks from daily living?" You know, somebody cuts their fingers slicing vegetables in the kitchen. A person bumps up against something really hard, scrapes their skin, and now they have a portal for bacteria to get in there. At the same time, you'll occasionally encounter a patient with a benign murmur who tells you, "I've always been told I needed to take an antibiotic before I uh went to the dentist." And an example of benign murmur would be what's often called a physiologic murmur, a flow murmur, um that type of thing. And you might say, well, okay, the person has a history of a heart murmur. Shouldn't you just err on the side of safety and provide the prophylaxis? I get it. Infectious endocarditis is a life-threatening and life altering disease that requires many weeks of antimicrobial therapy usually delivered IV. At the same time, all antimicrobial therapy carries risk, including the risk of resistant pathogen development. Antimicrobials are great. They save lives. They save lives but should only be used when indicated by best evidence.

With that in mind, let's get back to the question. Go over the answers. A 72-year-old with a prosthetic aortic valve presents stating, "I've been told I have to take a medicine before I have a deep dental cleaning. Concurrent health issues include hypertension, type 2 diabetes and dyslipidemia currently a treatment goals. Medications include metformin, hydrochlorothiazide, telmisartan and rosuvastatin. She has no drug allergies. Which of the following is the most appropriate next step in her care? And by the way, we're given that she is on one, two, three, four different meds. None of the antimicrobials mentioned here have any drug-drug interaction potential with her meds. So back to the answer. Amoxicillin 2 grams PO 30 to 60 minutes prior to the procedure. This is of course the correct answer and is the first line med for IE prophylaxis in the absence of penicillin allergy which of course is the most common scenario. Select oral streptococcus species are the most common pathogen in IE if it occurs post dental work. And where did that strep come from? came from the mouth with IE associated with injection drug use. Staph species are often implicated. Obviously, that's not what we're talking about here. And with giving it prior to the procedure, the antimicrobial is there to do its magic while the bacteria from the mouth is being forced into the bloodstream. Now I also want you to just think for a minute. Hopefully all of us get our teeth cleaned on a regular basis, right? Same thing happens to us. We have bacteria introduced into the bloodstream, but our immune system takes care of it. We've got a person here with a prosthetic valve. So she has increased endocarditis risk. 

Now option B. Amoxicillin 2 grams PO 1 to 2 hours after the procedure. Well, right drug, wrong time. You want the medicine on board prior to the procedure. The time when the problematic bacteria would be entering the bloodstream. 

C. Cephalexin 2 grams 30 to 60 minutes prior to the procedure. Okay. Right time giving it ahead of time but wrong drug. Cephalexin use is typically limited to people with penicillin allergy for this purpose in the absence of anaphylaxis. And if the person does not have penicillin allergy, then amox is definitely the first line drug. 

And then option D inform the patient that no antimicrobial prophylaxis is needed during dental care. This of course is incorrect as we know in this clinical scenario IE prophylaxis is advised. Key takeaway clinical practice changes over time. Knowledge of the latest guidelines is needed to provide up to-date care and yield NP board success.

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