Asthma

Background

 

Asthma is defined as reversible airway obstruction. Our airways start with our windpipe or trachea, and then divide into two main air tubes to each lung. They continue to divide into smaller and smaller tubes until they end in the air sacs where oxygen and carbon dioxide are exchanged. Asthma affects the small air tubes called bronchioles.

 

During an asthma attack the air tubes become narrowed, making it harder for air to move through them. This results in symptoms such as coughing, a sensation of chest, heaviness, or the feeling of it being hard to breathe. Most commonly in young children we see them using extra muscles to breathe. This is called work of breathing. See this video: https://www.youtube.com/watch?v=Radr3Fr_Nro. If the air tubes are narrowed enough, you can hear the air moving through them, similar to when you purse your lips to whistle. This noise is called wheezing. Wheezing is a breathing out noise.

 

This picture shows how the airways become narrowed. As a result, the amount of room for the air to move through is smaller.

 

 

There are two main things that happened to cause narrowing of the air tubes, inflammation and bronchoconstriction. Inflammation means, swelling, and bronchoconstriction means squeezing.

 

Our air tubes are lined with the same kind of tissue that lines the inside of our nose. This tissue is called mucosa. When we get sick, such as from a viral infection, that tissue gets swollen, and secretes mucus. If the virus moves down into our lungs, the same thing can happen in our air tubes resulting in less space for the air to move through. This is inflammation.

 

The walls of our air tubes have muscle in them. If the muscles get irritated, they squeeze which narrows the airways.

 

There are many different triggers for asthma. Some cause inflammation, some cause bronchoconstriction, and some cause combinations of both. Everyone has different triggers and different degrees of inflammation and bronchoconstriction from any specific trigger. Regardless, it results in narrowing of the airways, which makes it harder to breathe.

 

Common triggers include viral infections, cold air, exercise, allergies, strong smells, and chemical irritants.

 

What To Do

 

As there are two different components to asthma (inflammation and bronchoconstriction), we need to use two different types of medication to treat it.

 

1. Inhaled steroids- these treat the inflammation. The most commonly used inhaled steroid in paediatrics is called fluticasone (brand name Flovent). It is an orange puffer. There are 3 different dose strengths that are each a different shade of orange. As inflammation is a chronic process, the inhaled steroid medication is often called the preventative medicine. This is because it doesn't work immediately. Your child needs to be on it on a regular basis to prevent them from having inflammation when exposed to a trigger. It will work in reducing inflammation once it's already happened, but at that point, your child is already sick and symptomatic, which is too late and defeats the purpose.

 

2. Bronchodilators - these treat the bronchoconstriction. The usual bronchodilator is called salbutamol (brand name Ventolin). This is the blue puffer. As the bronchodilator medications work fairly quickly, they are called reliever medications. They are used only when needed.

 

These puffers must be used with a spacer. It doesn't matter how old you are, if you don't use a spacer all you're doing is spraying the medication in your mouth and it doesn't get into your lungs where it's needed.

 

For kids over the age of 11, there are other kinds of inhalers that don't need spacers. Many of these are also combination products with the inhaled steroid and the bronchodilator in one inhaler.

 

As everyone's asthma is different, your child will be given an asthma action plan. This includes which inhaled steroid and bronchodilator to use, what dose, and when they should be used. There will be a maintenance plan, which is what medications to use when your child doesn't have symptoms, and with the intent to prevent them from having a symptom flare. There will also be instructions on how to manage symptoms. There are other medications that are used to manage asthma in certain circumstances. Montelukast is an antihistamine that has a good effect in people who have an allergic component to their asthma. In the case of a significant asthma flare other drugs may be added to the treatment plan, most usually an oral steroid called dexamethasone.

 

Just as everyone's asthma is different, the types of symptoms that they have may vary. They may also be different with different triggers. The parents of young children will need to learn their child’s symptoms. A common misconception is that parents think that every cough is asthma. There are many different kinds of coughs and only some of them are asthma. Children with asthma can still have other kinds of coughs. If you are not sure, you can always try the reliever medication to see if it works. Older children can tell you if they are having symptoms and if they need the reliever medication.

 

When To Be Concerned:

 

The doctor will discuss something called "the safety line" in your child's asthma action plan. This is the amount of reliever medication you can use. If the maximum number of puffs is not relieving symptoms or your child needs to use the reliever medication more frequently than every four hours then they need to be seen by a doctor. Depending on how much trouble breathing they are having will be how you decide where and when they need to be seen. If they are really struggling or a maximum number of reliever puffs doesn't do very much then obviously you go immediately to the emergency department. However, if your child is fairly comfortably when you are at the safety line, then it could wait until the next morning to be seen in clinic. You as a parent, need to make that decision based on how your child looks. However, it is important that you always get seen when your child hits the safety line.

 

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