Pediatric (Childhood) Asthma: Diagnosis & Treatment

00:01 How do we truly diagnose asthma? On your exam they may mention spirometry with post bronchodilator response.

00:12 Typically, they’ll give something like a methacholine challenge and look to see if they can create bronchoconstriction.

00:19 A response of around 20% is indicative that this patient is reacting to the methacholine challenge.

00:28 The reality is that we don’t typically use this test, it’s probably not cost-effective.

00:34 The vast majority of children, we simply use a history of responsiveness to albuterol and other stigmata, like eczema, to make the diagnosis of asthma.

00:46 Rapid viral testing is not helpful.

00:49 Viruses can be a trigger for asthma.

00:52 Viruses can happen in patients with bronchiolitis, too And the sad issue is, is that if you look at healthy children walking down the street, one in four will test positive for a virus.

01:05 So, viral testing has a low positive and a low negative predictive value.

01:13 Consider allergy testing or pulmonary function testing really only in children who are over five years of age, who you’re having a hard time controlling or you’re really not certain of what the diagnosis might be.

01:27 For a child with a previous diagnosis of asthma, who is coming with an asthma exacerbation, we are not going to typically get labs or x-rays.

01:35 We simply treat the patient.

01:38 For hospitalized children with no history of wheezing, a chest x-ray is usually done.

01:44 This is because, again, while we’re going to start off presuming this child may have asthma, it’s also possible the child has another problem which you haven’t figured out yet.

01:54 An example would be a foreign body or another condition, maybe a pulmonary lymph node that’s compressing the airway.

02:02 This is the kind of thing where they can look very similar at first, and then over time you notice they really aren’t responding to the albuterol like you might expect.

02:10 A chest x-ray can sometimes be helpful in distinguishing between these problems.

02:16 So, back to asthma.

02:18 We have a patient who is coming in with an acuter exacerbation.

02:22 They’re wheezing, they’re right there in your office.

02:24 What are you going to do? Well, for the acute exacerbation, the mainstay is albuterol.

02:30 Albuterol is a powerful beta-agonist.

02:33 It’s going to cause bronchodilation and allow those airways to really open up.

02:38 Patients should feel relief relatively quickly.

02:42 There is an available levoalbuterol or racemic albuterol.

02:47 It’s more expensive, but not more effective, so most people don’t use it.

02:51 Sometimes we use it because it may have less cardiotoxicity to children with underlying cardiac conditions.

02:58 But for the vast majority of patients with asthma, it’s not necessary.

03:04 Additionally, during an acute exacerbation we are going to give systemic steroids.

03:09 This can be oral or it can be IV or it can be intramuscular.

03:14 Neither route is better than another, they all take about two hours to kick in.

03:19 If you recall, it’s a complicated pathway that steroids take to actually reduce inflammation.

03:26 The steroid has to make it into the nucleus of the cell, which then changes via transcription factors the production of both prostaglandins and leukotrienes.

03:36 There’s this back filled pathway that if you apply a steroid it takes about two hours before you’re going to really notice those steroids kicking in, but they will kick in in two hours, so get them started as soon as you can.

03:51 The other important thing in an acute exacerbation, it is a learning moment.

03:55 So perhaps not while they’re acutely ill, but after they’ve started to get better, it’s a good time to counsel about triggers because prevention is what asthma care is all about.

04:08 So in the acute setting you may see more than just albuterol used.

04:12 If the albuterol really isn’t turning the child around the corner, they may use continuous albuterol through a nebulized machine, but there are other medications that can help as well.

04:22 An example would be magnesium.

04:24 Magnesium is a 2+ ion just like calcium and, thus, is a competitive inhibitor in the sarcoplasmic reticulum of the smooth muscle cell inside the airway.

04:35 So the magnesium is going to allow that airway to relax.

04:39 Side effect though is that it really relaxes all your smooth muscle, and so, you may develop hypotension.

04:46 Terbutaline is sort of like IV albuterol, it’s intravenous.

04:51 But in children with albuterol, it’s given IV and it’ll cause more of that smooth muscle dilatation and usually a profound tachycardia.

05:00 Children on terbutaline are usually watched in the ICU setting.

05:05 When they’re in the ICU setting you’ll note that we like to avoid intubation.

05:11 If a patient is in respiratory distress from, say, a trauma or a bad pneumonia, we usually will go get around to intubating them pretty quickly.

05:20 In asthma, we’re going to generally drag our heels on that and the reason is, remember, asthma is a problem with getting the air out.

05:28 If I now intubate the child, I’m going to be pushing more air in, and I’m worried about a pneumothorax, where that lung may actually pop and air may escape into the side of my chest wall causing a pneumothorax.

05:41 That’s not very good.

05:43 There are some other agents that can help.

05:45 Ketamine is a bronchodilator and some of the inhalational agents like halothane or bronchodilators.

05:51 There are many different agents we can use in the ICU setting to help dilate those smooth muscles.

05:58 So in a hospitalized child who is not in the ICU, how are we going to manage these children? Well, generally, we’re going to start off with continuous albuterol.

06:06 In some places, they do that on the wards, in some places, that’s in the ICU setting only.

06:11 And generally, you’re going to have a continuous nebulizer of albuterol at very high doses.

06:17 Then, when the patient is feeling better, they’ll generally transition to every two hours or Q2.

06:23 We’ll watch them, we’ll use asthma scores to see how they’re doing, and once they’ve been stable for a few treatments we’ll switch them to Q4 or every four hours.

06:32 At that time, they’re almost ready to be discharged, and in most settings we’ll wait for two Q4 hour treatments, and if they’re still looking good they’re okay to go home.

06:42 We typically discharge them if they do not have an oxygen requirement, if they do not need albuterol more than every four hours for at least two episodes, and if they don’t have respiratory distress.