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A Pilot PANRE Hack: RSV vs Pertussis

CME4Life cme4life By May 27, 2022No Comments

I want to share with you a studying hack for the Pilot PANRE. This hack works for any standardized test, especially in medicine. It worked with the PANCE and PANRE in old. It’s going to be useful on the upcoming PANRE as well.

If you’ve ever worked in academia, you know writing test questions isn’t difficult. It’s easy to write a question. What’s difficult is coming up with plausible distractors. You can write a question with an answer; that’s super easy. But how do you add in other reasonable answers? That’s what makes a good test question.

What I’ve found in teaching board review courses and working in colleges is that anytime there’s a disease with similars, meaning that two diseases are separate and have different treatment but look the same, you better know them like the back of your hand.

An example would be croup and epiglottitis. They’re both infections of the throat that give you airway obstructions. However, they’re very different; one’s viral and one’s bacterial. You have to know the differences like the back of your hand. The same thing is true of Crohn’s and ulcerative colitis, or pterygium and pinguecula, or hordeolum and chalazion, or actinic keratosis and seborrheic keratosis. These are all similar, but very different.

When you study, focus on how you tell the difference. This is something we stress in our board review courses and our videos. We even have a product called PA Prep: Janus, which compares all of these diseases. Today, I want to talk about two diseases that are similar yet different. You need to be mindful of them and be ready to separate them.

RSV and Pertussis

The presentation of these diseases is a sickly kid, under the age of six months. They have a viral URI-like presentation and lots of it is very benign, just a benign prodrome.

Please remember though: any kid less than two months old with a fever receives a full workup and admission. If you have a six-week-old with a temp of 101.6, they’re getting admitted. They’re getting IV antibiotics, an LP, cath urine, chest radiograph and blood cultures.

So, I’m really talking about infants between the age of two and six months. Why am I talking about respiratory syncytial virus (RSV) and pertussis in infants? Because both of these diseases have potentially lethal complications.


Don’t think of RSV as respiratory syncytial virus. Think of it as RS wheeze because these patients come in with a cold and they’re wheezing. This is also known as bronchiolitis, inflammation of the small airways.

Literature shows that if they have positive RSV swabs, nasal swabs, there’s an increased risk of death. That puts you in a position to admit them, and you should. At the very least, you should talk to your supervising doc about the vital signs and their baseline. I want to know if a kid with RSV is sickly. Do they have a history of cardiopulmonary problems? You need to look at their history, as well as ask their parents, “At what age gestation were they born?” “How long were they in the hospital for?” That second one is the million-dollar question. If they were in the hospital for a day or two, they were fine. If they were in the hospital for two weeks, they weren’t fine. That makes me more concerned.

Understand that running RSVs liberally on sick kids is kind of running D-dimes liberally. It can get you into some trouble. I run RSVs selectively, but with any infant between two and six months, with a URI and wheezing, I’m very concerned about RSV. That’s a reasonable time to do a nasal swab for RSV. If they’re positive, one of the admission possibilities is Ribavirin, but that will be referred to inpatient medicine.


Pertussis is a little trickier, in that there are some buzzwords here. First and foremost, it’s Bordetella, a highly contagious gram-negative germ. Here’s how I remember that: there are two s’s in pertussis and two l’s in Bordetella.

Normally, people are protected against pertussis with their DPT (diphtheria, tetanus and pertussis) shot. As we become adolescent young adults, the protection weans, so pertussis is a little more contagious in young adults. It’s transmitted aerosolized, similar to mycoplasma. There are three distinct phases. It’s similar to Lyme disease and syphilis in the fact that it has three different presentations.

If I asked you how Lyme disease presents, you would have to ask, “What phase is it in?” In primary Lyme, there are erythema migraines; in primary syphilis, they’ll have that painless ulcer. Phase two looks different, as does phase three. The same is true of pertussis, which makes it a bit tricky. Here’s how I remember that: pertussis has three s’s in it, just like there are three different phases.

There’s the catarrhal phase, the paroxysmal phase and the convalescent phase, or CPC. Catarrhal means inflammation of the mucous membranes, especially the respiratory tract, with excessive secretions. In this phase, they’re really congested with rhinorrhea. They’re producing a lot of gook. The initial phase is when they’re most contagious. Next is the paroxysmal phase. This is the long-acting inspiratory whoops, and it can last two to three months.

Again, the usual presentation is kids less than six months old and they have these paroxysmal coughs. Often, they cough so much that the barrel receptors in the lungs cause them to vomit. So, there’s this emesis and they can have some degree of apnea as well.

Pertussis is bacterial, but it’s a little tricky. This is the only situation I’ve ever seen in medicine where a bacterial disease gives you lymphocytosis. Lymphocytosis is typically seen with viral infections. Diagnostically, the gold standard is going to be the nasal pharyngeal swab, similar to RSV. The treatment for less than six months is inpatient and Azithromycin for 10 days. We have to be really careful of close contact precautions so it isn’t transmitted to others. A couple of years ago, the CDC recommended including acellular pertussis in everyone’s immunizations because of an outbreak.

If you are sitting for the Pilot PANRE, this is one of the hacks you should be using to help you succeed. However, the old PANCE and PANRE were a lot trickier than what the NCCPA is doing now. For the Pilot PANRE, you just need to know good, solid, walking-around medicine. That’s a really good thing.

The best hack I can give to you is to tell you to really know good medicine. Know that when you have an infant under six months old, sure they could have a cold. It could also be RSV or pertussis; know how to work that up.

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