Asthma Symptoms Pathophysiology Triggers Severity Of Asthma

Asthma Symptoms Pathophysiology Triggers Severity Of Asthma

Updated on July 5, 2024

Do you know about asthma symptoms, the pathophysiology of asthma, triggers of asthma, and the severity of asthma? Asthma is a very common condition that often comes up when you are talking about NCLEX-RN, HAAD, MOH, and DHA or any Govt exams for nursing officers in India. This review of Asthma is part of the series for nurses preparing to sit licensing exams which includes NCLEX-RN, HAAD, MOH, and DHA. Although the content is mainly focused on nurses, anyone who would like to know about asthma can get piece of knowledge about Asthma. Let’s continue with the topic.

Asthma Symptoms Pathophysiology Triggers And Severity Of Asthma

This is part 1 of the review of asthma. In this article, Rinta Rajan explaining about the pathophysiology, triggers and severity of asthma.

When you are talking about NCLEX-RN, HAAD, MOH and DHA or any Govt exams for a nursing officer in India, a very common condition that often comes up is Asthma. Before we get started I would like to inform you that the topic review of Asthma is in two parts. In this article, Part 1 we will be dealing with certain aspects of Asthma and Part 2 will deal with the rest of the nursing management, medical management interview questions or discussions about Asthma.

What is Asthma?

Asthma is a chronic inflammatory disorder that obstructs the small airways. This is primarily a problem of the smaller airways In the image you can see the larger Airways and smaller airways.

Asthma Symptoms Causes
Asthma Symptoms Causes

As much predominantly of problems, there is inflammation and constriction of the smaller airways. If you take a closer look at these smaller airways we have a layer which is the lumen. After that, a layer of cells contains mucus-producing cells and many other cells that are lying over there. There is a layer of mucus kind of covering the lumen. Then you have a third layer known as the lamina propria. In a short while, we will be talking about what is lamina propria. Finally, we have an outer layer which is a layer of smooth muscle. So this is what the normal smaller Airways Cut section looks like. It’s important to remember all of these layouts because we are going to talk a lot about these layers as they progress in this topic.

Asthma symptoms – closer view of layers

Now let’s take a closer view of each of these layers and what happens in each of these layers.

Asthma layers
Asthma – Closer view of layers

As we have already mentioned we have this layer of mucus and outside that layer of mucus we have another layer of cells. So all those cells produce mucus and many other cells and outside that layer, we have another layer which is known as the lamina propria. And outside the lamina propria, we have a layer of smooth muscle.

We have a layer of cells, the mucus-producing cells also known as the Goblet cells, lamina propria. Then the basement membrane. Then you come to the layer which is the lamina propria layer. The lamina propria contains small capillaries, it also contains mast cells. In a short while, we come to mast cells. For the time being you need to remember that there are cells in the lamina propria. There are also many other special cells, WBC cells, T helper cells, and immune cells present. And finally, outside that, we have the layer of smooth muscles. So this is what is present in a normal person.

How does the same structure look in a person who had as a person who has asthma?

In a person who has asthma, what is going to happen is, that the mucosal layer is going to be a lot thicker because there is a lot of mucus production. Now since there is a lot of mucus production you have many Goblet cells. So mucus-producing cells are more in number as compared to a normal person. Somebody who does not have asthma has less number of Goblet cells, mucus-producing cells.

For somebody who already has more Goblet the basement membrane is thicker. So you got a thicker basement membrane. As we have already discussed we are talking about the lamina propria. In a patient who has asthma or who is asthmatic, they have more number of mast cells. Also, have a larger number of Eosinophils and other immune cells, WBC or T helper cells whatever it is.

Before we go into what are the implications of all of these we are going to take a closer look at our mast cell. Mast cell contains pockets and inside them and this is filled with histamine. So this has got a batch of histamines inside them. So we are talking about histamine.


Histamines are responsible for allergic reactions. Histamines mediate or they are the main ingredients for allergic reactions. This is why in allergy we provide patients with anti-histamine medications and antihistamine works against the histamine. So histamines are a very very important thing when we are going to be talking about asthma and hence mast cells have got their own significance.

What are mast cells going to do?

Now you can appreciate the fact that what are mast cells going to do? The number of mast cells in an asthmatic patient is high, which means that there is going to be large amounts of histamine fills. The number of mucous glands, the mucus-producing cells are high which means that there is going to be more amount of mucus production. And now you know that this could be more amount of mucus production. The lumen is going to be much narrower than you would expect in a normal person because of a lot of mucus production, because of this thickening of this layer. All of this is going to constrict and the lumen is going to be narrower or smaller in a patient who has asthma. That’s basically the difference between an airway of a normal healthy adult and the airway of an asthmatic patient.

What are the triggers for an asthmatic attack? – Asthma symptoms

What are the triggers or in other words the precipitating factors for an asthmatic attack or exacerbation of asthma? We know that if somebody has asthma, it doesn’t mean that all the time they need to have the symptoms of asthma. They can be perfectly alright, but at certain points of time when there is a precipitating event, even there is a trigger that can lead to exacerbation of the symptoms, or in other words that can lead to an asthmatic attack. So these precipitating factors or these triggers are going to be different in different individuals. But I have tried to cover up as many triggers as possible but there could be other triggers also to somebody to get an asthmatic attack.

Precipitating factors
Asthma Precipitating factors

1. Environmental triggers – Asthma

The first kind of trigger is environmental triggers or factors. Environmental factors can include dust, pollution or fumes coming from the exhaust. It can also include animal dander, pollen, fragrances from certain perfumes, it can happen due to cigarette smoke, it can happen even when there is a sudden change in the weather. So climatic conditions or weather conditions can also trigger an asthmatic attack. So all of these come under environmental factors.

2. Physiological factors – Asthma

Next, we have the physiological factors. In physiological factors, it could be because of an underlying disease condition or some other free moment condition that the client already has. For example, this could be any kind of viral upper respiratory tract infection, it could be Sinusitis, it could also be in certain cases because of Gastroesophageal Reflux disorder or it can also be hormonal changes that can trigger an asthmatic attack. It can also happen because of stress which is the gain of physiological factors.

3.  Medication – precipitating factor of asthma

The third kind of precipitating factor is medication. To be very specific one common medication that can cause an asthmatic attack is Aspirin which is acetylsalicylic acid. Another medication is beta-blockers. Beta-blockers can trigger an asthmatic attack. In some people, NSAIDs can also trigger an asthmatic attack.

4. Occupational exposure – precipitating factor of asthma

The Fourth kind of precipitating factor is occupational exposure. The occupational exposure is getting exposed to certain metal salts, asbestosis. It could be because of certain dust or fumes at workplaces, it could be because of plastic if it is a plastic production unit or industrial chemicals. So all of these can trigger an asthmatic attack.

5.  Food additives – precipitating factor of asthma

And finally, we also have certain food additives which can be a trigger to asthmatic patients. Food additives include such as sulphites, it could also be monosodium glutamate which is a very common food additive. And it could also be that some people can have dried shrimp, beer or wine as a trigger for asthma. 

As mentioned before it is not necessary that everybody is going to have the same kind of precipitating factors and triggers, it could differ from person to person.

What happens when there is an exacerbation of asthma?

What exactly happens when an allergen or a trigger reaches the airways of an asthmatic patient?

Take a look at what exactly happens when an allergen for a trigger reaches the airways of an asthmatic patient. From the previous drawings that we have already seen that we have got a layer of mucus. So that is the second layer of cells, these are mucus-producing Goblet cells and then comes the lamina propria layer, blood cells, mast cells, certain immune cells and finally a layer of smooth muscles.

Exacerbation of asthma
What exactly happens when an allergen or a trigger reaches the airways of an asthmatic patient?

Now let’s just say that we have allergen coming. So let’s say that there is a trigger there is an allergen that has come in, it could be animal dander, dust or anything for that matter. Now when these allergens come in we know that in order to get rid of this foreign body of allergens that coming in, goblet cells are going to produce a lot of mucus. So there is increased mucus production, that’s one thing.

Now when these allergens are coming in something happens in this lamina propria. It’s normal for the body to release certain antibodies when it detects that there is an allergen coming in. And the body produces IGE which is Immunoglobulin E. Function of immunoglobulin E is to fight against the allergen. So now we have these allergens and the body produced this Immunoglobulin E.

Now we also have allergens. Immunoglobulin E binds to the allergens. We have the Immunoglobulin E and the allergens bound. So Immunoglobulin E is binding to the allergens. After it binds to the allergens what it does is it goes to the mast cells. Now Immunoglobulin E and the allergens complex reaches the mast cells. Mast cells have receptors.  Immunoglobulin E and the allergens complex is going to bind to the mast cells. So that is going to happen.

So we have all of these IGE and allergen complex coming in attaching to this mast cell preceptor. As a result, what is going to happen?

As a result, the mast cell is going to get destabilised and it’s going to open up and it’s going to throw out. In fact, all these pockets are going to burst open and are going to throw out all of that histamine. Now we need to remember that this is happening over here. So all these histamines are spilling out. Histamines are spilling out along with these mast cells also have something known as leukotriene. So the leukotrienes are also spilled out. So what do we have here?

We have here is, increased histamine release, as well as a lot of leukotrienes, are released. Along with that we also need to remember that we have got these immune cells over here. These immune cells are going to start inflammation the process of inflammation. So we got increased mucus production, we got a lot of histamine-releasing, leukotriene releasing, we got inflammation. And these histamines and leukotrienes are going to affect the smooth muscles and the smooth muscles are going to constrict which is going to lead to Bronchoconstriction. So this is what happens to a patient who has asthma and happens to come into contact with the trigger or a precipitating factor.

So there are a large amount of mucus production, extremely large amounts of mucus production, we have the smooth muscles constricting. So what’s going to happen specifically to the lumen. The lumen is going to be narrowed down further. And when the lumen is narrowed down further, the patient is not able to exhale the air. It going to cause problems with his oxygenation status.

So this is what happens in asthma, this is what happens when there is an exacerbation of asthma. 

Assessment findings – Asthma

What kind of assessment findings are you going to see?

Asthma Assessment findings
Assessment Findings Of Asthma

1. Restlessness – The client can have restlessness.

2. Wheezing – There is going to be wheezing because the lumen of the airways is narrowed down and the patient is finding it very difficult to exhale the air so wheezing is present. 

3. Crackles – Then Crackles that is inflammation so there is a chance that there are a lot of secretions are going to get formed and when air passes through all of the secretions the client can present with crackles.

4. Absent or diminished lungs sound – There is absent or diminished lungs sound because at certain areas in the lungs air may not reach.

4. Hyperresonance – There is hyper resonance, and this can happen because they can get trapped inside all the air that is not coming out. 

5. Use of accessory muscles for breathing – Because the patient is not able to maintain his oxygen level, so is trying hard to breathe and that causing the use of accessory muscles for breathing.

6. Tachypnea with hyperventilation – There can be Tachypnea with hyperventilation.

7. Prolonged exhalation – There is prolonged exhalation in an attempt to throw out all of that carbon dioxide.

8. Tachycardia – There is Tachycardia

9. Diaphoresis – There is Diaphoresis

10. Cyanosis  – There is Cyanosis

11. Decreased oxygen saturation levels – There can be a decrease in the oxygen saturation levels.

Also most of the time it is seen that the client has a cough. 

The severity of asthma 

Based on the severity of the symptoms asthma can be classified as:

  • Mild intermittent
  • Mild persistent
  • Moderate persistent
  • Severe persistent

What does this mean?

Mild intermittent asthma

It simply means that in mild intermittent asthma, as the name suggests, it is mild and intermittent. So it is not something that they continue, as it happens sometimes. So if you look at the frequency of the daytime symptoms, the date and symptoms are usually less than two per week and at night time symptoms are usually less than two per month. So the symptoms are so less as it is so mild, it is so intermittent and that at the most the patient may experience symptoms for 2 times a week during the day and night time which is a nocturnal symptom he may experience just less than 2 times in a month. 

Asthma severity
Asthma severity

Mild persistent asthma

If you look at the mild persistent once during the daytime symptom it could be more than two per week or equal to more than two per week and the nighttime symptoms can be more than two 2 per month.

Moderate persistent asthma

If you look at the moderate persistent, symptoms, the daytime symptoms can happen on a daily basis. The daytime symptoms are happening on a daily basis. It is moderate but it is persistent. And the nighttime frequency increases to more than once per week.

Severe persistent asthma

If you look at the severe persistent as the name suggests it’s absolutely severe, the daytime symptoms are continuous. So the client has continuous symptoms. And the nighttime symptoms are also continued throughout the night. So here we are talking about a very very severe condition, wherein the client has to be hospitalised and is a very high and very frequent exacerbation cause limitations in the activity of the client.

This is how asthma is classified according to its severity, that is severity based on the frequency of symptoms.

Why is this important to know the severity? It is important because based on the severity, the medical management, the medical treatment is going to be planned for this patient.


I hope asthma symptoms, the pathophysiology, what happens in asthma and the triggers are clear to you now. Do check out the part 2 article when it is published, where we will be discussing medical management and nursing management. 

If you or your family members have any asthma symptoms, don’t ignore them. Consult a doctor and follow his advice. Health is wealth.

Do you think any asthma symptoms were missed in the article?

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References: YouTube Rinta Rajan


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