Bronchial Asthma

Bronchial asthma is a clinical condition where a reaction within the airways causes it to become narrowed, resulting in wheeze and breathlessness. It is a common condition that requires long term treatment that is aimed at reducing the number of attacks a patient experiences every year.

In this article, we shall discuss why asthma occurs, what symptoms and signs the patient may present with and how this condition can be managed.


Bronchial asthma is a common clinical condition, and can occur at any age. Studies have shown that over 23 million people worldwide suffer from asthma1, with adult men and women showing the same prevalence.

Why it occurs

The main underlying feature of bronchial asthma is inflammation of the airway. The inflammation is mediated via the protein immunoglobulin E (IgE), and results in recruitment of a number of different inflammatory cells. These release a number of mediators that result in the swelling (edema), mucus collection and narrowing of the airways (broncho-constriction).

As a result, the air can get trapped in the lungs and result in hyperinflation.

Narrowing of the airways that occurs in Asthma

In the presence of triggers of asthma such as dust, dog dander, pollen and cat fur (to name a few), mediators that cause inflammation are released, causing the airways to narrow significantly. This causes breathlessness and if untreated can result in severe asthma.

Clinical features

1. Symptoms

The primary symptom that patients present with in asthma is breathlessness with wheeze. The wheeze is usually expiratory and is easily audible with a stethoscope, unless the attack is severe, in which case the chest may be silent due to poor air entry.

Typically wheeze sounds like a musical note and has a high pitched character to it. Attacks of asthma are usually brought on by a viral or bacterial infection, and patients may cough out thick yellow phlegm. Recurrent dry cough can also be a symptom.
Patients may also experience breathlessness when trying to perform activities
of daily living, especially if the condition is poorly controlled. Exercise can
bring on asthma as well in susceptible patients.

Many patients with asthma start of by developing symptoms at night. This usually manifests as recurrent cough, and has been attributed to a greater degree of inflammation of the airways in the lungs.

2. Signs

On examination, patients appear short ofbreath, have a high respiratory rate (breathing may be shallow) and have low oxygen levels on pulse oximetry.

A pulse oximeter

Patients may have other signs suggestive of sinusitis, nasal polyps and rhinitis. In the case of severe attacks, the patients may be cyanosed (blue), will be unable to speak in full sentences due to extreme breathlessness and can have a high heart rate. Such patients require urgent admission and emergency treatment.

In patients who have associated signs of an allergic reaction, atopic dermatitis, skin eczema and even conjunctival redness may be seen.


A diagnosis of bronchial asthma is primarily made from clinical history. Patients usually have a family history of asthma, and may have had episodes of hay fever, sinusitis, rhinitis or nasal polyps. There are a number of tests that will be performed to confirm the diagnosis –

1. Blood tests – Patients who suffer from asthma have a high count of a particular cell called the eosinophil. This is a characteristic feature. Sputum samples will also have high eosinophil counts. However, an absence of eosinophilia does not rule out asthma as a diagnosis.

2. Pulse Oximetry – Here a probe is placed on a finger and an estimate of the amount of oxygen present in the blood is made. It is a useful non-invasive test, but is not as accurate as an arterial blood gas analysis.

3. Arterial blood gases – This involves taking a blood sample from an artery and determining the amount of oxygen and carbon dioxide in the blood. It is a good indicator of how severe the asthma is, and how it should be

4. Chest X-ray – This test helps determine whether there is an underlying infection in the chest. In the absence of an infection, the x-ray can be normal.

5. Pulmonary function tests – This is where the patient is asked to blow hard into a tube that is connected to a machine. The machine then provides an accurate reading of how much air there is in the lungs, how much the patient is able to blow out and in essence tell the doctor about what the lung capacity is. In asthma, this will be reduced, but the
degree of reduction is reversible with medication.

6. Skin allergy testing – This can be useful to identify any triggers that can result in an asthma attack.


The primary treatment strategy in asthma is opening up the airways using bronchodilator drugs. Treatment is offered in a step-wise approach, starting with preventative measures along with short acting or long acting drugs.

Different kind of inhalers used in Asthma

Rather than talk through individual drugs, let’s discuss the step wise approach as laid out by the National Heart, Lung and Blood Institute2

Degree of Severity First line treatment Other options


Degree of Severity


First line treatment

Other options

Intermittent asthma Short acting beta-2 agonist (Salbutamol)
Mild asthma Low dose inhaled steroid Long acting Theophylline or leukotriene modifier
Moderate asthma Steroid inhaler with long acting beta-2 agonist Theophylline and leukotriene modifier drugs
Severe asthma High dose steroids with long acting beta-2 agonists.
Leukotriene modifying drugs are also administered along with oral steroids
and oral beta-2 agonists.


Bronchial asthma is a common clinical condition that warrants early diagnosis. With the available options, patients can lead a good quality of life and enjoy the activities that they enjoy.


1. Tarlo SM, Balmes J, Balkissoon R, Beach J, Beckett W, Bernstein D, et al. Diagnosis and management of work-related asthma: American College Of Chest Physicians Consensus Statement. Chest. Sep 2008;134(3 Suppl):1S-41S.

2. National Heart, Lung, and Blood Institute. Education for a partnership in asthma care. Expert panel report 3: guidelines for the diagnosis and management of asthma. National Asthma Education and Prevention Program (NAEPP). Aug 2007.