This Kid Had Bronchiolitis

"Heart rate 162, respirations 75, and his sat is only 86%... Her temp is 38.8."

She had nasal flaring, coarse lung sounds with inspiratory/expiratory wheezing, and some subcostal and intercostal retractions with slightly sunken fontanels and an occasional cough. 

She was sleepy, but she interacted with her mom okay. Mom was VERY anxious.

The patient was a 5-month-old female without any medical problems or known allergies. She had coryzal symptoms - the hallmarks of an upper respiratory tract infection - for the last 1-2 days before her difficulty breathing started tonight. She lives with Mom, Dad, and an older brother - all of whom have been well. It's believed she "picked up a bug" from daycare.

It was the beginning of January - right in the middle of RSV season. We did this call every night. This kid had bronchiolitis.

Bronchiolitis is an acute inflammatory disease, usually caused by a viral infection of the lower respiratory tract. This is generally only a problem in kids < 2 years old and is primarily caused by RSV.

Spoiler alert: This kid ended up being RSV-positive.

What happens is RSV gets down into the lower airways and wreaks a bunch of havoc. Any bug being where it shouldn't be causes a reaction from the body. The body tries to get rid of invaders by throwing water and WBCs at it - causing inflammation and edema. So you get this inflammatory response and edema in the airways. Then, RSV does something extra special - it directly attacks the ciliated epithelial cells in the airway causing narcosis and sloughing of the dead cells into the lumen. Along with inflammation and this sloughing you get increased mucus production. The body attempts to get rid of the debris.

Normally how this works is that debris gets caught up in the mucus and the whole mess is moved up the ciliated escalator to the throat/mouth where it gets coughed up. That's the whole greenish/yellow phlegm grossness that's normally seen with viral illness. In RSV however, because those ciliated cells get destroyed, there is no cilia to move the mucus up... so it builds up in the airway.

So now you have this situation where there are these smaller, lower airways that are swollen, inflamed, covered in mucus, with these balls of debris/mucus stuck in there, narrowing the lumen even more.

In adults, this is usually fine. Adults airways are big enough and their cough is generally strong enough to still move air and cough the crap up. Little kids, however, esp those under the age of 2, have REALLY tiny airways. They are super easy to block... So you get both mucus plugging resulting in areas of collapse and luminal narrowing, similar to asthma. Ultimately, this all results in hypoxia, V/Q mismatch, atelectasis, and compensatory hyperventilation.

These kiddos almost always present with standard upper respiratory symptoms, also called coryzal symptoms. These usually include nasal congestion, rhinorrhea (runny nose), sore throat, and cough accompanied by some anorexia and sometimes a low-grade fever. After a couple of days of these symptoms, the kid usually begins to have a bit of a wheeze and some SOB as the lower airways become affected. After that, you get increased WOB, tachypnea, coarse lungs, accessory muscle usage, grunting, lethargy, etc., usually around days 3-4 (if at all). In wee little ones (<6 months) apnea can actually be an associated symptom.

The differential for these patients usually includes bronchiolitis, pneumonia, and asthma, unless the patient has a weird history of congenital heart disease, interstitial lung disease, etc. Usually, asthma isn't diagnosed in kids under 2-3. Unless they also have a history of eczema, reactive airway disease, or a lack of preceding respiratory symptoms. You can also have asthma that is triggered by a respiratory infection, so it can be very hard to differentiate. Pneumonia isn't very common in kids and a major cause of pneumonia in kids is RSV/respiratory viruses. Patients can have concurrent pneumonia with their bronchiolitis - the two are not mutually exclusive. Personally, I err on the side of bronchialitis in kids under 2 with SOB.

When we talk about bronchiolitis we are talking about a spectrum of disease. These kids can run the gambit from mild, essentially perfectly fine with a cough, to extremis. Mild cases, and even most moderate cases, are usually self-limiting and don't require intervention. They can be managed at home with minimal training and equipment. More severe patients often require oxygenation or ventilation support and admission into the hospital. Technically this kiddo is very sick. They have severe bronchiolitis.

So how do we treat it? What do we do?

Really, not a lot. The name of the game is supportive care. The key is to support breathing.

Airway management is important, but not for intubation. In fact, you want to avoid that if at all possible... For me, when I think of "airway" for these kids, I'm thinking of suctioning. More specifically, nasal suctioning. I always try to suction these kids out.

We did this - there was a transient increase in SpO2 and a decrease in WOB, but not sustained.

Next is breathing, right? And this is the key for these kids. They have both a V/Q mismatch problem and a hypoxia problem. Once they get tired, they have a hypercardia problem. The goal is a SpO2  >90% in the acute setting. Generally, these kids do well with CPAP or high-flow nasal cannula (HFNC), both of which have been shown to reduce the work of breathing. Unfortunately, most EMS systems are unable to support the use of HFNC due to a lack of equipment (ventilator capable of HFNC) and oxygen reserves - it should be noted that some ALS services do use this intervention. CPAP, particularly nasal CPAP with a RAM cannula, is the other option. Neither has been show to be superior to the other.

We did not carry either option for a kiddo this small. We simply placed them on a NC at 6 LPM which improved the SpO2 to 91% - I'll take it.

From a circulatory perspective, these kids tend to be dehydrated. In a mild case, an IV is almost never required. However, in this particular case, we felt it beneficial. We were able to get access pretty easily, actually. We initiated a fluid bolus.

Really, that's it 99% of the time.

The American Academy of Pediatrics does not recommend the routine use of albuterol, epi, or steroids in bronchiolitis. None of them have proven benefits. Some sources essentially say you can try albuterol, esp. if there is a family history of asthma, but if there isn't an improvement, stop. So we stopped there.

But before I end the post, I want to address intubation... There are times these kids may need to be intubated. These are a minority of cases, even in severe disease, and this by no means should be a first-line procedure. However, some indications where it can be considered include persistent hypoxia despite other appropriate interventions (aka failing CPAP/HFNC), depressed mental status, severe hypercarbia, and fatigue with poor respiratory effort (kiddo is getting tired). Again, this is a last resort and can almost always be avoided in the prehospital environment. These kid's mucus plugging and airway restriction gets much worse post-intubation and they are a disaster to manage on a vent.

The name of the game: Supportive care.

Thanks for reading! Check out the references and as always, if you have any questions, post them below!

-Dean Stockley

References:

Carter, H & I Barata. Ch 18: The Not-So-Happy Wheezer. Pediatric Medical Emergencies. Oxford University Press, 2020.

Ostermayer, D., R. Donaldson, P. Lin, et al. Bronchiolitis (peds). WikiEM. Last edited Nov 2023. Access from: https://wikem.org/wiki/Bronchiolitis_(peds)

Piedra, PA. Bronchiolitis in infants and children: Treatment, outcome, and prevention. UpToDate. Last updated Nov 2023. Accessed from: https://www.uptodate.com/.../bronchiolitis-in-infants-and…

Shorette, A. Case 4. Pediatric Emergency Medicine: Chief Complaints and Differential Diagnosis. Cambridge University Press, 2018.

W Brunow de Carvalho, MC Machado Fonseca, C Jonston & DG Nichols. Ch. 25: Pneumonia and Bronchiolitis. Roger's Handbook of Pediatric Intensive Care, 5th Ed. Wolters Kluwer, 2017.