Mycoplasma pneumoniae

In this episode we dive into the resurgence of Mycoplasma pneumoniae—an atypical bacterial cause of community-acquired pneumonia that’s making waves in pediatric emergency medicine. We’ll cover its clinical presentation, epidemiology, diagnostic approach, and management, including why standard beta-lactam antibiotics won’t work. Plus, we’ll discuss whether M. pneumoniae even needs to be treated in the first place!

Learning Objectives

• Describe the clinical presentation, epidemiology, and complications of Mycoplasma pneumoniae infections in pediatric patients, including its atypical manifestations.
• Differentiate Mycoplasma pneumoniae pneumonia from typical bacterial and viral pneumonia based on history, physical exam findings, and diagnostic testing.
• Assess the current evidence for antibiotic treatment of Mycoplasma pneumoniae and justify treatment decisions based on patient presentation, severity, and potential complications.

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References

Vallejo, Jesus G. “Mycoplasma Pneumoniae Infection in Children.” UpToDate, 1 Nov. 2024, www.uptodate.com/contents/mycoplasma-pneumoniae-infection-in-children.

Garcia T, Florin TA, Leonard J, Shah SS, Ruddy RM, Wallihan R, Desai AP, Alter S, El-Assal O, Marzec S, Keaton M, Yun KW, Leber AL, Mejias A, Cohen DM, Ramilo O, Ambroggio L; Children’s Hospitals Initiative for Research in Pneumonia (CHIRP). Clinical Features and Management Strategies in Children With Mycoplasma Pneumoniae. Pediatr Emerg Care. 2025 Feb 17. doi: 10.1097/PEC.0000000000003338. Epub ahead of print. PMID: 39960098.

Gao L, Sun Y. Laboratory diagnosis and treatment of Mycoplasma pneumoniae infection in children: a review. Ann Med. 2024 Dec;56(1):2386636. doi: 10.1080/07853890.2024.2386636. Epub 2024 Aug 3. PMID: 39097794; PMCID: PMC11299444.

Shah SS. Mycoplasma pneumoniae as a Cause of Community-Acquired Pneumonia in Children. Clin Infect Dis 2019; 68:13.

“Mycoplasma Pneumoniae Infections Have Been Increasing.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 18 Oct. 2024, www.cdc.gov/ncird/whats-new/mycoplasma-pneumoniae-infections-have-been-increasing.html.

Transcript

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

 Welcome to PEMCurrents, the Pediatric Emergency Medicine Podcast. As always, I’m your host, Brad Sobolewski, and today we’re focusing on a pathogen that has been making waves in pediatric emergency departments across the country. Mycoplasma pneumoniae. Whether you know it or not, you’ve likely seen a surge where you work.

Patients are presenting with community acquired pneumonia that isn’t responding to standard beta lactam antibiotics, or with parents who are just concerned that their child has walking pneumonia. That’s because mycoplasma pneumonia is just a little bit different than most of the pathogens that we deal with in children.

So let’s dive in. So, what is it? Microbiology lecture. Warning, med school trigger. Uh, so Mycoplasma pneumoniae is a small, obligate intracellular bacterium and it lacks a cell wall. So that’s why it doesn’t respond to beta lactam antibiotics like penicillin and amoxicillin and cephalosporins. Instead, it requires macrolides, tetracyclines, or fluoroquinolones for treatment.

It’s spread via respiratory droplets and thrives in crowded environments such as schools and daycare centers. It binds to the epithelial cells in the upper and lower respiratory tract, triggering an immune response that leads to mucosal damage, increased mucus production, and impaired gas exchange. So mycoplasma pneumonia infections have been on the rise, especially in children.

After a lull during the COVID 19 pandemic, cases reemerged in 2023 and continued to climb into 2024. Historically, mycoplasma pneumonia has been most common in children aged 5 to 17 years and young adults. But what’s new is that we’ve seen a striking increase in infections among children aged 2 to 4.

Per the CDC, diagnosed mycoplasma infections increased steadily through the summer of 2024, peaking in August for 2 to 4 year olds and 5 to 17 year old age groups. There’s also been an increase in diagnosis in those under 12 months of age. This is all notable because these infections have historically been thought to affect school aged children much, much more than younger children.

All right, let’s talk about clinical features. So the incubation period for mycoplasma pneumonia can be around two to three weeks. Symptoms often start gradually, with fever, headache, malaise, and sore throat, preceding the onset of a persistent dry cough. Unlike classic or typical bacterial pneumonia, which has abrupt onset in focal lung findings, mycoplasma pneumonia patients often present with a prolonged worsening cough that can persist for weeks to months.

The name walking pneumonia was coined because people with this mild form of respiratory infection can still walk around and do their normal activities. It’s attributed to, but not exclusive to, mycoplasma disease. Now some patients can develop severe pulmonary complications, fortunately those are rare.

These include respiratory failure, pleural effusions, necrotizing pneumonia, and pyema. Beyond the lungs, mycoplasma pneumonia is a weird bug, and it can also cause some extra pulmonary manifestations. So you can get mucocutaneous disease, including erythema multiforme. and mycoplasma induced rash and mucositis, also known as RIME, and even Stevens Johnson syndrome.

Patients can get joint pain, you can have a hemolytic anemia due to IgM antibodies causing an autoimmune hemolysis, or even neurological complications such as meningoencephalitis, seizures, transverse myelitis, or even Guillain Barre syndrome. Alright, so making the diagnosis starts with having a firm understanding of bacterial versus viral etiologies of pneumonia.

And generally, we should make this diagnosis clinically. So typical bacterial pneumonia, like streptococcus pneumoniae, is more likely when symptoms such as fever, chills, cough, and focal chest pain start abruptly. These patients often have respiratory distress or tachypnea and focal lung findings like rails or crackles or decreased breath sounds.

A typical bacterial pneumonia, like mycoplasma pneumonia, presents with a gradual onset of fever, headache, malaise, sore throat, followed by the worsening non productive cough. It’s often accompanied by wheezing and or rails, and fever and illness are typically milder. than in the classic bacterial pneumonia.

Now viral pneumonia, which is also all over the place, and due to RSV, parainfluenza, influenza, adenovirus, and more, is more common in children under 5 years of age. The cough develops gradually following an upper respiratory tract infection, and lung findings are diffuse and bilateral, often with wheezing.

Think of viral pneumonia like bronchiolitis, but in a preschooler instead of a baby. And so while mycoplasma pneumonia is often a clinical diagnosis based on presentation, there is some confirmatory testing. PCR testing of the nasopharynx, or throat, is highly sensitive and specific. You can get serology, which will detect IgM and IgG antibodies.

It’s useful, but it takes longer to result. The caveat of these serologic tests is that There’s probably a lot of seropositivity without symptoms in the general population. So basically, many people could have positive mycoplasma without symptoms. There are no distinguishing features on blood labs like CBC and blood culture, which are generally not necessary in these patients unless they’re critically ill.

And the chest x ray findings, if you need them, will typically show bilateral patchy infiltrates, though some cases can have unilateral lobar consolidations. So as you might imagine, chest x rays aren’t as useful as you’d think in diagnosing mycoplasma. When it comes to management, first and foremost, supportive care.

Treat fever, ensure adequate hydration, and provide respiratory support as needed, like if kids need oxygen, that sort of stuff. Cough suppressants and cough medicines are generally ineffective and no better than honey, and really not recommended in many age groups, but if you’ve got a middle schooler or teenager and parents want to try it, eh, have at it.

Or don’t. Before I talk about antibiotics, I do want to bring up the question as to whether or not we actually have to treat mycoplasma in the first place. Studies supporting antibiotic treatment of documented mycoplasma pneumoniae in children are limited. Supports provided predominantly by in vitro studies, a randomized trial in military recruits, and some observational studies in which inclusion of mycoplasma pneumoniae specific therapy was associated with a decreased risk of treatment failure.

So, whether that’s a change in antimicrobial therapy or a hospital admission, or length of stay in children with community acquired pneumonia, but they didn’t have etiologic data in that study. There was a systematic review of 17 studies, including 4, 294 patients, where they found insufficient evidence for the efficacy of antimicrobial treatment of mycoplasma pneumonia, lower respiratory tract infection in children less than 17 years of age.

There was publication bias, heterogeneity, and lack of blinding. We also don’t know whether administration of antibiotics decreases the incidence or severity of associated mucocutaneous disease. And I’m not even going to get into pans or pandas here. I can’t bear it. So, yes, I’m going to talk about antibiotics.

But consider this scenario, you’ve got a kid, cough and wheezing, you think it’s a virus, maybe it actually is mycoplasma, there’s a good chance they’ll be fine anyway, even if you don’t treat it. So yes, think of mycoplasma pneumoniae, but don’t make it your sole focus when you’re really just dealing with viral pneumonia in a lot of kids.

Okay, the first line treatment is azithromycin. The ZBA is actually all right, so it’s 10 milligram per kilogram in one dose, max dose of 500 milligrams. That could be orally or IV on the first day, and then five milligram per kilogram in one dose. Maximum dose of 250 milligrams for the next four days. If azithro is unavailable, or in the case of an allergy, you could use doxycycline two to four mgs per kg per day, orally or iv.

in one or twice daily dosing. The max daily dose is 200 milligrams, and it’s done for seven days. Compared with other tetracycline antibiotics, doxy is much less likely to cause permanent tooth discoloration in young children, and it can be given safely for less than 21 days to children of all ages.

Tetracycline for kids greater than eight years of age, and azithromycin are also options, but azithromycin has lots of GI side effects. For immunocompromised children, especially with previous exposure to macrolides, fluoroquinolones like levofloxacin are an alternative initial agent. Fluoroquinolones are bacteriocidal rather than bacteriostatic, and the dosing for levofloxacin varies according to age.

So greater than six months but less than five years. Levofloxacin is 8 10 mg per kg per dose orally or IV every 12 hours. The max total daily dose is 750 mg and you treat for 7 10 days. For kids older than 5 years, you do Levofloxacin 10 mg per kg per dose once per day orally or IV. And that max dose is again, 750 milligrams per day for seven to 10 days.

All right, so let’s talk about some take home points. So mycoplasma pneumonia is back with a vengeance after the COVID 19 pandemic, and it is affecting younger children more than ever before, especially kids, two to four years of age. For most patients, it is a clinical diagnosis. You should think about it, though, in kids with classic presentations, or in a child who has failed treatment with beta lactams for a presumed community acquired pneumonia.

And don’t fear the Z Pak, right? If you diagnose mycoplasma pneumonia, macrolides and zithromycin are the first line treatment. Fluoroquinolones are good for immunocompromised children. Mycoplasma can cause extrapulmonary disease. So, go online and look up some pictures of the mucocutaneous manifestations.

There are also hematologic and neurologic complications. And keep an eye on outbreaks and community trends. The epidemiology is shifting, and infections are rising, so your hospital should have a local plan to deal with infection in your community. Thank you so much for listening to this episode. If you found it helpful, let me know.

Leave a review, send a message on social media or email, and share it with your colleagues and learners. And as always, as my 13 year old would say, don’t forget to like and subscribe. For PEMCurrents, the Pediatric Emergency Medicine Podcast, this has been Brad Sobolewski. See you next time.