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Asthma

Asthma is an inflammatory disorder.  Even in mild asthma there is inflammation. Recurrent episodes of wheezing asma, shortness of breath, chest tightness, coughing. The key symptom in kids is coughing. Not wheezing. Prolonged cough in children, especially at night or in the morning, is asthma until proven otherwise. Asthma obviously has three main components, and weíll talk about these in depth. The airway obstruction is due to bronchoconstriction, mucus production, as well as local edema. The inflammation is key and the inflammation leads to

Increased airway responsiveness; what this means is that the airways in asthmatics constrict too quickly, too easily. After you have a cold, and you are a little kid, and you get your asthma, for about the next six weeks any mild stimulus will make you react more quickly and more severely than if you had been fine for about two or three months. Those can be very non-specific stimuli, like cigarette smoke or change in temperature. Things like that. We see this as increased 

Onset of asthma; this is a childhood disease. Eighty percent of all asthmatics present by five-years-of-age. It is more common in boys in childhood. It is about equally common in boys and girls during teen years, and then it is more common in women as adults. The risk of developing asthma; very heavily weighted on a genetic basis. Overall the incidence of asthma around the country is about 7%, but if just one parent has asthma you jumped up to about a 

What about the wheezing infant? Weíve all had the kid who comes in with bronchiolitis. And he wheezes. Maybe he comes in a second time with a cold and he wheezes. What can you tell parents about the likelihood of them growing out of it? If you look at children who have wheezed once in the first three years of life - and these are usually due to things like RSV or other viral 

Common triggers; most common trigger, under about 3-5 years of age, RSV. Most common trigger after five-years-of-age thatís viral, is actually rhinovirus. Interestingly, a virus that 

Give oxygen, you can always take if off if they get better. Keep their O2 sats above 95%. You are not going to hurt them. Frequent high dose steroids and systemic steroids are other things that weíll talk about right now in more detail. Short-acting agonists. They are not going to ask you what the dose is, but they might say, "You have a child presenting with asthma, with wheezing, his peak flow is this Ö which one of the following might be reasonable treatments?" and certainly albuterol is the drug that we tend to use. High dose frequently, every 15 to 30 

Anticholinergics, ipratropium; a lot of stuff recently in Pediatrics and some of the other journals suggesting that if you use this in an acute asthmatic we can actually decrease hospitalization rates in the sickest of kids. It acts as an inhibitor of acetylcholine at the parasympathetic receptors, it takes a little longer to have an onset than albuterol, maybe works a little bit longer. The key

Oral steroids; these are the indications. These are pretty straightforward. If itís a severe exacerbation, moderate to severe, you just go ahead and use them. If they are not responding well to the albuterol, if they are using steroids recently, the fourth one there. You always go home with one more medication than 

Theophylline; fallen out of favor for most uses in asthma. It still has a few areas where we will consider using it. Not indicated in the emergency room. It wonít get kids out of the emergency room. It wonít help you prevent them from being admitted. Thereís no evidence in kids who are well enough to be on the hospital floor that it has any advantage over optimal beta agonist treatment. And certainly now, with the addition of ipratropium, really thereís not much use on the hospital floor. In the ICU itís still up for grabs. Nobody has ever really done hard-core studies looking at ICU patients, and yeah, to be honest, if youíve got a kid going down the tubes itís still used occasionally. And weíll talk about the limited role in chronic asthma.

Magnesium; itís been in the news on and off. It is a bronchodilator. It has an onset within a few minutes. We think it lasts about two or three hours. One big disadvantage, youíve got to give it IV. It doesnít work when itís nebulized and if you give it too fast it can cause a little hypotension and bradycardia. Exact role, still not known. If youíve got a kid real sick in the ER a lot of people will give a dose or two, but it actually isnít clear when it should be used.

When can you send the patient home? Basically when they are pretty much better. They shouldnít be hypoxic. They can have some wheezing but they should be better. And their peak flow should be about 70% and sustained, as a good rough guideline. The key thing is you have to be able to follow up on the patient, theyíve got to be able to give the medications, theyíve got to be able to come back if they get sicker.

Okay, letís talk real quickly about chronic asthma. The National Heart/Lung Institute has had two documents out over the last about five or six years. The Expert Panelís Report on Asthma. If you guys are actually general pediatricians and take care of asthmatics, get on their web site and download the Expert Panel II. A wonderful document talking about all the different aspects of asthma. This is the new classification therapy. Asthmatics are either intermittent, and by definition they have to be mild, and if they are not mild they become persistent asthmatics with varying severity. And weíll talk about how to treat each of these in a second. The way you categorize these kids into these areas depends on a couple of different things. It depends on how frequently they are having nocturnal symptoms, how often do they have breakthrough symptoms during the week that you have to use additional albuterol. How much is their asthma affecting their activity or their life? What is their normal peak flow when they are well. You donít need to know the details for the Boards, although it would be useful for you as a general pediatrician.

Our drugs are now in two groups; rescue agents, which are for your exacerbations, and the long-term control agents, which is the new preferred term. Notice that bronchodilators in general are not long term control agents. Kids arenít supposed to be on bronchodilators on a daily basis unless they are very very severe.

Letís talk about cromolyn. Still the first choice. Why? Not because itís the best drug but because it has no side effects. It tends to block the early and late response, it helps in exercise asthma, it reduces airway hyper-responsiveness, but itís slow. Generally it take 2-6 weeks before you see an onset and itís not effective in everybody. And thereís some evidence that it may not be all that effective in the young kids. Unfortunately thatís where we are using it a lot because it comes in a nebulized formulation and we donít have a nebulized steroid yet. The other thing is, if you use the MDI itís fairly expensive compared to inhaled steroids. But again, if they ask you, "What drug would be appropriate to start on a four-year-old who is having mild persistent asthma and needs a preventive drug?" this would be your first line drug.

Tilade or nedocromil; you can think of this - even though it is chemically different - think of it as a super-cromolyn. It has the same lack of any significant side effects and it works a little quicker. So you will actually see an improvement within a few days even. You often see changes in the pulmonary functions to as early as a few weeks. The only side effect is that in about 15-20% of patients theyíll take a puff on this thing and theyíll refuse to ever take it again and say it just tastes horrible. And youíll take it and take a puff and you donít taste a thing. "Are you crazy? Whatís wrong with you?" Thereís this idiosyncratic reaction to taste. But other than that, no real side effects. Again, itís indicated for mild persistent asthma and can be used for exercise induced asthma. So kind of cromolyn plus is the way to think of it.

Inhaled steroids; still far and away the best long-term preventive agent for asthma, period. The problem is potential side effects. If basically decreases the late response. It doesnít stop the initial bronchoconstriction but also deals with the hyper-responsiveness and you can see improvement within a few days in lung function, on inhaled steroids. Maxing out at about 2-4 weeks. You might want to know the dosage range for whatís considered low, medium, high, as a standard. Itís based off beclomethasone, which is the older steroid that weíve all used. About 200-400 mcg per day is low dose, and medium is 400-800. This will be useful when you talk about side effects.

What are the side effects of inhaled steroids? First of all, if you use a spacer, you decrease all of the side effects dramatically. Youíll see in the studies that look at effects on growth, the kids who use dry powder inhalers where a lot of it hits the back of the throat, or where they are not using a spacer, they have a lot more potential growth suppression than those that use a spacer. Use a spacer. It cuts down on side effects. In adults occasionally you get thrush or you get a