Understanding Pertussis: Clinical Insights and Public Health Challenges

In this episode of PEM Currents: The Pediatric Emergency Medicine Podcast, we explore pertussis, also known as whooping cough – a disease that remains a public health challenge despite widespread vaccination efforts. We will review the clinical presentation, diagnostic strategies, management protocols, infection control practices, and vaccination updates. This episode also covers what healthcare providers need to know about post-exposure prophylaxis, respiratory precautions, and managing occupational exposures.

Learning Objectives

1. Understand the clinical progression of pertussis through its three distinct stages and identify key symptoms, including age-specific presentations in infants and older children.
2. Implement effective management strategies for pertussis, including supportive care, appropriate antibiotic regimens, and post-exposure prophylaxis for contacts and healthcare providers.
3. Promote pertussis prevention by understanding vaccination schedules (DTaP vs. Tdap), addressing vaccine hesitancy, and adhering to infection control protocols in clinical settings.

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How about a fun AI song about whooping cough?

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References

StatPearls
Lauria AM, Zabbo CP. Pertussis. [Updated 2022 Oct 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519008/

AAP Pediatrics in Review
Heather L. Daniels, Camille Sabella; Bordetella pertussis (Pertussis). Pediatr Rev May 2018; 39 (5): 247–257. https://doi.org/10.1542/pir.2017-0229

UpToDate

Yeh S et al. Pertussis infection in infants and children: Clinical features and diagnosis. UpToDate. Available at: https://www.uptodate.com. Accessed December 3, 2024.

MMWR

Seither R, Yusuf OB, Dramann D, et al. Coverage with Selected Vaccines and Exemption Rates Among Children in Kindergarten — United States, 2023–24 School Year. MMWR Morb Mortal Wkly Rep 2024;73:925–932. DOI: http://dx.doi.org/10.15585/mmwr.mm7341a3

Transcript

Note: This transcript was partially completed with the use of the Descript AI

Welcome to PEM Currents, the pediatric emergency medicine podcast. As always, I’m your host, Brad Sobolewski, and today we’re talking about pertussis, a disease that is challenging clinicians and public health officials alike. Despite being vaccine preventable, Pertussis is on the rise, yet again, fueled by declining vaccination rates, waning immunity, and the fact that people can’t stop coughing on each other.

In this episode, we’ll go over clinical presentation, diagnosis management, infection control, and post exposure protocols. So pertussis, or whooping cough, is caused by Bordetella pertussis, a gram negative coccobacillus. It definitely spreads via respiratory droplets, and has no environmental or animal reservoirs, making humans the sole carriers.

The incubation period averages about 7 to 10 days, and the disease progresses through some distinct clinical stages, which I will go over in a moment. Pertussis has been recognized since the 16th century. I was not practicing medicine back then. Um, with the first documented epidemic occurring in Paris in 1578.

Bordetella pertussis was isolated in 1906 by Belgian researchers, Jules Bordet and Octave Gengou, I hopefully I pronounced them right, but they’re long gone, so they won’t be mad at me,, leading to the development of a whole cell pertussis vaccine in the 1940s. Introduction of the DTP, the diphtheria tetanus pertussis vaccine, dramatically reduced disease incidence overall.

In the 1990s, we got the acellular pertussis vaccine, the DTaP, which replaced the whole cell formulation due to concerns about some side effects. So pertussis remains endemic in many regions of the world despite vaccination efforts. During the 23 24 school year, DTaP coverage among kindergartners in the United States dropped to 92.

3%, which is below the 95 percent threshold needed for herd immunity. That is is why we’re seeing an outbreak now. This is a pretty troubling trend that began during the COVID 19 pandemic and has just gotten worse since. The exemption rate for vaccines rose to 3. 3 percent. This is the highest on record.

Non medical exemptions accounted for over 93 percent of these exemptions. And 14 states in the U. S. have reported exemption rates exceeding 5 percent. Idaho is leading at 14. 3 percent. So the implications of these declining vaccination coverage rates are significant and that’s why we’re seeing more and more outbreaks, especially putting our vulnerable populations at highest risk.

Alright, let’s get back to the clinical presentation. Wait, what’s that sound? Hold on. Coughing. Yeah, so that’s the whoop and the cough of pertussis. And I’d wager that many of you have not yet heard that clinically, so that’s why I included it on this episode. So here’s the stages of disease. First is the catarrhal stage, which lasts one to two weeks.

You have rhinorrhea, mild cough, and a low grade fever, if any. You are highly contagious during this phase, but it’s often unrecognized as pertussis. Then, in the next two to eight weeks, you have the paroxysmal stage. You have these severe paroxysms of coughing, the inspiratory whoop right beforehand, post tussive emesis.

Infants, especially under six months of age, may present atypically with just apnea, cyanosis, or bradycardia. for that. Following that, you have the convalescent stage, which lasts weeks to months. You have gradual resolution of symptoms, though residual cough may persist. That’s why they call it the 100 day cough.

Aside from coughing forever, there’s some important complications you need to be aware of. And they can be severe, especially, as I noted earlier, in young infants. So respiratory complications include apnea, secondary bacterial pneumonia, and pulmonary hypertension. Children encephalopathy, often due to hypoxia.

And the mechanical complications can include rib fractures, subconjunctival hemorrhage, and even rectal prolapse due to intense coughing and valsalva. Greater than 50 percent of kids under 12 months of age with pertussis could require hospitalization. 50 percent of those kids will have apnea, 20 percent will have pneumonia, and up to 1 percent will die.

Encephalopathy occurs in about 20 percent of mortality cases, probably due to hypoxia, or maybe the toxin produced by the bacteria itself. So, making the diagnosis of pertussis starts with high index of clinical suspicion. Early diagnosis, as you’d suspect, is critical to limiting disease spread and initiating treatment.

So, PCR testing, which is widely available now, has high sensitivity in the first three to four weeks and is the preferred diagnostic test. Culture is the old gold standard, but it’s slower and less sensitive. It can take up to a week to grow. CBC might show significant lymphocytosis, um, most often in infants, but it ain’t going to make the diagnosis of pertussis for you.

And a chest x ray will just show you some non specific findings, such as peribronchial thickening in severe cases. And unless you’re worried about concomitant bacterial pneumonia, you probably don’t need a chest x ray to make the diagnosis of pertussis. You can get an isolated pertussis PCR, or Or it can come as part of a respiratory panel.

But remember those comprehensive viral respiratory panels cost 1, 600. So if you’re just worried about pertussis, don’t get the whole panel. So management starts with supportive care. Infants with apnea, cyanosis, or feeding difficulties should obviously be admitted to the hospital. They may need oxygen and or nutritional support.

And you definitely have to watch those kids very closely for the complications such as hypoxia and secondary infections. Remember, a tiny baby with pertussis can go apneic at a moment’s notice even without a persistent cough. Antibiotics reduce transmission. But do not significantly alter disease progression once the paroxysmal stage begins.

So again, you are treating with antibiotics to prevent more people from getting sick, more so than shortening the duration of illness. The main antibiotic that we use is azithromycin. For infants under 6 months of age, that’s 10mg per kg daily for 5 days. For children older than 6 months of age, 10mg per kg, max of 500mg on day 1, followed by 5mg per kg per day, max of 250mg on days 2 through 5.

That is the same dosing that you can give to a grown up. An alternative treatment, you would be trimethoprim sulfamethoxazole for patients who are allergic to macrolides. Post exposure prophylaxis is recommended for household contacts, so the people that the index patient lives with, any high risk individual, and infant, pregnant women, or immune compromised individuals that have been in any sort of contact with the person with pertussis, and and a health care worker exposed without appropriate PPE.

Again, pertussis spreads through respiratory droplets. So this necessitates strict infection control. So that starts in triage. So if you think that a patient has pertussis, then they need to be place on droplet precautions as soon as they are assessed. You wear a surgical mask and eye protection, so goggles or a face shield, and you want to maintain these precautions for five days after starting effective antibiotics or for 21 days if the patient is untreated.

As a clinician, Just ask yourself, did you wear appropriate PPE, mask and goggles? Don’t get lazy. Was the exposure prolonged or close? And rely on infection control in your institution to help decide whether or not you need post exposure prophylaxis. If you’re vaccinated and you wore PPE, you don’t need anything.

Unless you have symptoms. If you’re vaccinated and you did not wear PPE, then prophylaxis is recommended. If you’re unvaccinated and not up to date, well then what are you doing in healthcare? And immediate prophylaxis and vaccination update are required. And, okay, ’cause I just mentioned it. Let’s talk about vaccines.

So first I wanna talk about DTaP, dt, lowercase a uppercase p and t dap. Uppercase T D A P. So DTAP contain higher concentrations of diphtheria and pertussis antigens. It’s used for children under seven years of age. TDAP contains lower antigen concentrations and it’s designed for adolescents and adults to reduce reactogenicity.

There is no standalone pertussis vaccine. I’ve had patients say, well, I don’t want tetanus. Just give me the pertussis one. Well, tough Schenectes. We do not have a pertussis vaccine. alone. It’s only available in combination with diphtheria and tetanus toxoids, DTaP or Tdap. The combined vaccine boosts efficacy and ensures broader protection against all of the included infections.

Now the routine vaccination schedule, which if you are a pediatric resident, you know, like the back of your hand, the DTAP is administered at 2, 4, 6, and then between 15 and 18 months with a booster at 4 to 6 years. The Tdap is one dose at 11 to 12 years and then during every pregnancy to confer passive immunity to the newborns.

And again, depending on when you’re listening to this, you may be in the midst of a pertussis outbreak. And if you listen to this a few years later, after the original publication date in the fall of 2024, and you’re seeing another pertussis outbreak, well, dang it, we haven’t done our job. We need to strengthen school vaccination requirements.

We need to educate parents about vaccine safety and the risks of exemptions. And we need to broadly improve and ensure access to vaccinations through our community clinics. Thanks. Alright, so that’s it for this episode on Pertussis, which remains a significant public health challenge due to its severe complications in young patients and the ongoing decline in vaccination coverage.

Healthcare providers play a vital role in diagnosing and managing it, preventing its spread, and educating patients and families about the benefits of vaccination. Infection control practices and post exposure protocols are critical for protecting both clinicians and close contacts and other exposures.

Thank you so much for listening to this episode. I hope you found it educational and informative. If there’s other topics that you want to hear about, let me know. I’m on X, I’m on Blue Sky, I’m on Mastodon, I take emails, you can leave a comment on the blog, you can leave a review on your favorite podcast site, any feedback is good feedback, and encourage your colleagues to listen, and as the kids say, like and subscribe, I told my 12 year old I would say that at the end of the episode.

For PEMCurrents, the Pediatric Emergency Medicine Podcast, this has been Brad Sobolewski, see you next time.