HSV Diagnosis for New Nurse Practitioners
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Show notes:
So often in primary care, patients come in asking for testing for herpes, whether they have symptoms or not. Sometimes it’s because they “want to be tested for everything,” or are concerned about an exposure from a partner. As a new nurse practitioner, I wasn’t always confident about the best approach.
HSV Diagnosis in Primary Care
In this week’s video, I’m covering:
When to consider HSV, and the unlikely ways it can present
What the difference between primary, non-primary initial and recurrent infections are, and what it means for the patient
The top differential diagnoses to consider
How to test for HSV, what the gold standard tests are and what NOT to use
Lab Interpretation Crash Course
If you liked this episode, it's a sneak preview of how we cover labs inside our comprehensive Lab Interpretation Crash Course. It covers CBC, CMP, Urinalysis, Dipstick & Microscopy, TSH, Lipids & top Endocrine labs in primary care, and comes with lifetime access and continuing education credits! Check it out here.
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Hey there, welcome to the Real World NP podcast. I'm Liz Rohr, family nurse practitioner, educator,
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and founder of Real World NP, an educational company for nurse practitioners in primary
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care. I'm on a mission to equip and guide new nurse practitioners so that they can
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feel confident, capable, and take the best care of their patients. If you're looking for clinical
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pearls and practice tips without the fluff, you're in the right place. Make sure you subscribe and
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leave a review so you won't miss an episode. Plus you'll find links to all the episodes with
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extra goodies over at realworldnp.com slash podcast. So this week I'm going to be talking
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about HSV types 1 and 2, and the overall approach to diagnosis, including the lab testing. So when
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it comes to HSV, it is incredibly common. So HSV1 and HSV2, statistics estimate about 1 in 6
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patients have HSV1, and about 1 in 20 people have HSV2. It is a lifelong infection that
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hangs out inside of the trigeminal ganglia or the sacral ganglia, depending on the
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site of infection. And in fact, HSV1 has been thought of as the oral infection when it can
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affect either oral or genital locations. Same thing with HSV2. And the reason I give those
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statistics and this other statistic, I tried to find as many as I could. Only interestingly,
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it's based on population studies, of course. So the data varies, right? But for the most part,
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sounds like about only 20 to 25 patients with HSV1 have ever had clinical symptoms. So it is
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very possible that somebody has that at lifelong infection, but they have never had symptoms and
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never will, which really ties into the testing and the patient counseling. Again, we'll circle
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back to that. So when it comes to the infection, symptoms tend to occur about 4 days
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after exposure, anywhere from 2 to 12 days. And then the symptoms that patients will get
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really depends on a couple of things. It depends on the site of infection, whether it's oral or
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genital. It depends if it's a primary infection or a non-primary initial infection or recurrent.
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So primary infections refer to when patients have never been exposed to either HSV1 or HSV2.
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And those situations of being seronegative, going to having an infection the first time,
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either strain, are more likely going to have more severe signs and symptoms.
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To be clear though, not everybody has a severe presentation, even if it's a primary infection.
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So some patients will have subclinical symptoms, something very mild, or they might be completely
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asymptomatic and become a carrier. Like I said, with HSV1, only 20 to 25% based on the studies
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that we have, have shown that those patients who have HSV1 in their systems have ever had
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clinical symptoms, right? So non-primary infections refer to when somebody has been
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exposed, for example, to HSV1 and then they become exposed to HSV2, the symptoms tend to
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be a lot more mild because even though they're two different viruses, they have enough in common
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that that initial protection from HSV1, HSV2, vice versa, will allow that kind of
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next iteration of infection to be a lot more mild typically. So the most kind of severe
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primary presentation when it comes to either oral or genital site, either HSV1 or HSV2,
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when it comes to the oral location, it actually in adults tends to present as a pharyngitis
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or as multiple oral lesions. And recurrent infections tend to be on the vermilion border,
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like the typical cold sore of what people think about, tends to be the recurrent infections and
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the initial infection. And so the more severe initial primary infections can have things like
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malaise, headache, fever, cervical lymphadenopathy, tonsillar exudate, about 40% of people,
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I understand, and as well as like some pharyngeal edema, too. So it can be a
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pretty significant presentation that sounds a lot like strep or initial presentation of HIV.
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It sounds like quite a number of things. So it could potentially be the initial infection
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either HSV1 or HSV2 just in the oral location. And so again, primary infection of either HSV1
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or HSV2 in the genital location can be really painful inguinal lymphadenopathy, again malaise,
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fatigue, headache, bilateral ulcerations. It can be vesicles, a grouping of vesicles on
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an erythematous base. But again, not everybody presents that way. That's kind of the classic
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textbook presentation. And I don't really have stats on that in terms of how many people
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present in that way, but just know that it can be shades of that presentation and it doesn't
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always have to be the exact one. And there's no real clear differentiation, clinically speaking,
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looking at the vesicles or ulcerations that go with HSV1 or HSV2. And most of the vesicles
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will progress to ulcerations that are exquisitely painful. And the duration of
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the infection tends to be longer and more severe with those primary infections versus
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the recurrent ones or the non-primary initial ones. And the symptoms can last for oral lesions can
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be about eight days or so of that exquisite pain. And then for an initial genital infection
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can be to the range of about 19 days. It can last a long time, but the recurrent infections
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tend to be a lot shorter, five to 10 days or so. So when it comes to recurrent infections,
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about 20 to 40% of patients, at least with HSV1, can have recurrent symptoms or recurrent
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outbreaks. I don't have great data on HSV2. I just couldn't find that. So I'm imagining it's
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very similar. Notably, HSV1 can be, when it's a genital infection, can cause recurrences in
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the first year, but typically doesn't cause recurrences after that. So if you have a
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patient with recurrent genital vesicles, typically that's going to be HSV2. And the
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of how often patients get recurrences and how severe they are can typically be correlated back
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to their initial presentation of how severe and how long of a duration their initial infections
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were. And that is a little bit predictive. It's really important though, regardless that
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we're letting patients know that it is likely majority of people, well, it's hard to say
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based on the statistics, but it's really important to counsel patients to expect a recurrence,
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except if it was in that case of HSV1, generally speaking, might not recur after the
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first year. But generally speaking, it's important to advise that there are recurrences.
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Okay, so differential diagnosis and then approach to diagnosis. So differential
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diagnosis is the first two infectious ones are syphilis that tends to occur as a painless
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indurated ulcer though, very different from HSV, which is quite painful. And then
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chancroid. That's how I've heard it pronounced. You might pronounce it differently. That can
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have a deep purulent ulcer with painful lymphadenopathy. So that sounds a little bit
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similar. So that's really important to keep in your differential. In terms of the non-infectious
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differential diagnoses, the top two ones are drug eruption, as well as the shets. So those
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are very uncommon, a lot more common to have HSV, but it's really important to keep those
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kind of top ones on your radar. Okay, when it comes to diagnosis. So like I said,
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it doesn't always commonly present as that textbook group of vesicles on an erythematous
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base. So it's really important to do testing. We can't, we officially cannot do a clinical
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diagnosis when it comes to HSV. And so the gold standard is actually to obtain via swab
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a PCR test and unroofing the vesicles so we can get to the epithelial cells, which is not a
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pleasant procedure for the patient. It is painful for the provider to have to do that,
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but that is the most accurate gold standard one. There's also the option of a viral culture
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that is kind of like second line to PCR. PCR can be a little bit expensive. So that's why
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we'll have a viral culture instead, a little bit more precise handling involved with that.
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And then below that are the Sanksmere TZ ANCK was what kind of used to be done,
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but PCR is really the gold standard now. So I'd recommend that you collaborate with your
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supervisor and your colleagues in your lab to see what the available options are and which
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specimens to obtain them with before you put a patient through that, just to clarify which
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test you're talking about and how to appropriately send it out so you don't have to do that to
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them again. A huge question I get is about serology. So patients coming in asymptomatic
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would like to have serologic testing. So number one, it is not recommended for
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screening and that is supported by USPSTF. The reason for that, and you may have
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talked about this already, but it's pre-test probability. And so if you're testing people
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with a low pre-test probability, a low likelihood of having HSV, it can lead to a lot more false
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positives, false positives and false negatives. So they're just really not that helpful.
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There are certain cases where we would consider it. So one specific thing I want to say,
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there's IgM and there's IgG. And like I said, there's the initial primary infection,
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the non-primary initial infection and recurrence. IgM is not helpful to distinguish between
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primary infection and recurrent. And when it comes to IgG, if you have an initial infection
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with somebody who has a positive IgG, it's not necessarily that helpful either. It's really
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important to get the PCR swab testing if we can. The most helpful situation is if you have
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somebody who has a partner with known HSV and the partner wants to know their status,
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you can send serology testing and it's most helpful if it's completely negative, right?
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Or if you have somebody who has a negative on file and your PCR by swab is positive
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now, it is most strongly supportive of an acute infection, right? But it's kind of
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and I really also harken back to what I said at the beginning of the video. If one in six people
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has HSV and only 20 to 25% of them have ever had symptoms, it's really not that helpful.
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And HSV is similar. I don't have the great stats on that, but it's a similar situation
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where one in 20 people have it and not everybody is symptomatic. And it's not
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recommended for screening. So I just have a conversation with them of, you know,
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it's important to have safe sexual practices to prevent transmission because asymptomatic
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transmission between episodes, viral shedding is possible. I don't have great data on that
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either, but it's definitely, unfortunately a possibility. So that's the overall approach
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to HSV diagnosis and testing. Please let me know what questions you have. If you haven't
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grabbed the ultimate resource guide for the new NP, head over to realworldnp.com slash guide.
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You'll get these videos sent straight to your inbox every week with notes from me,
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patient stories and bonuses that I really just don't share anywhere else. Also, as always,
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if you're struggling with your lab interpretation, definitely check out the lab interpretation
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crash course at realworldnp.com slash labs, the main labs in primary care. I'd love to help
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you out with that. Thank you so very much for watching. Hang in there and I'll see you soon.
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That's our episode for today. Thank you so much for listening.
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Make sure you subscribe, leave a review and tell all your NP friends so together we can help as
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many nurse practitioners as possible give the best care to their patients. If you haven't gotten
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your copy of the ultimate resource guide for the new NP, head over to realworldnp.com slash
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guide. You'll get these episodes sent straight to your inbox every week with notes from me,
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patient stories and extra bonuses I really just don't share anywhere else. Thank you so
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much again for listening. Take care and talk soon.
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