Asthma
Causes, Tests and Treatment for Asthma
Asthma is a condition that affects the lungs causing reversible airway inflammation and constriction that results in symptoms including wheeze, coughing, chest tightness and shortness of breath, which is more commonly known as an asthma attack.1
Asthma is a very common condition that affects over 300 million people worldwide and can affect adults as well as children. Asthma is a chronic condition that has no definitive cure, however inhaled medications, or puffers, are usually very effective at controlling the symptoms of asthma and preventing serious asthma attacks. Some people (especially children) may "grow out" of suffering from asthma, but others may have the disease for their entire lives.
Causes of Asthma
Asthma is caused by reversible inflammation of the small air passages or tubes of the lung (bronchi and bronchioles). This results in a narrowing of the tubes or passages and a reduced airflow to the rest of the lung.
When the airways are inflamed, the muscles around them tighten. This narrows the airways even more and allows less air to flow into the lungs. The walls of the airways can also swell, making the airways even narrower. Cells in the airways may make more mucus than normal. Mucus is a sticky, thick liquid that can further narrow the airways.2
Asthma is caused by a number of different environmental and genetic factors. Sometimes asthma is classified into allergic (atopic) and non-allergic (non-atopic) causes. Asthma is caused by "triggers" that result in the airway reacting to it and becoming inflamed. There are a wide variety of triggers that can cause asthma in different people including:
- pollens
- dust or mould
- animal dander or fur
- smoke or fumes
- sulfites (in food or wine)
- perfumes
- upper respiratory tract infection
- exposure to cold or heat
- physical exertion or exercise
- emotional excitement or stress
- medications
These are only some of the more common triggers, however there are many other causes that are not listed above.
The exact reason of what causes asthma and why some people are more sensitive to these "triggers" is not fully understood, but it is thought to be due to an overactive immune or allergic (atopic) response. Therefore people who have other allergic conditions such as hayfever and eczema are much more likely to suffer from asthma than those who do not have any allergies.3
Symptoms of Asthma
The symptoms of asthma are only present when a person is suffering from an asthma attack. An attack can be mild, moderate or severe and are usually caused by a trigger (see above). Wheeze is usually the most common symptom associated with asthma and is characterized by an audible noise when the person is breathing out (exhaling), however the absence of a wheeze does not mean that a person is not suffering from asthma. Common asthma symptoms include:
- wheeze
- cough
- chest tightness
- shortness of breath
More severe symptoms of an asthma attack will cause difficulty speaking, rapid, shallow breathing, bluish tinge around the lips and fingers and in the worst case loss of consciousness (fainting) and potential death.
Tests for Asthma
Investigations and tests for asthma are based on the severity and frequency of symptoms. Depending on whether a person is suffering from an asthma attack at the time or is currently well affects the type of tests performed to diagnose asthma. Some of the tests that are used to diagnose asthma include:
Peak Flow Meter
This is a simple tube that measures how forcefully you can blow out air from your lungs.
Spirometry
Spirometry is also known as lung function testing and involves a machine that measures how forcefully and the volume of air that you can blow out of your lungs. An inhaled medication may also sometimes be given during the test and the results compared to before the medication was given.
Oximetry
This involves placing an electronic probe on your fingertip that measures the concentration of oxygen in your blood.
Chest X-ray
This will sometimes be performed to assess the volume of your lungs and also whether there is any associated chest infection that may be the trigger of an asthma attack.
A clinical assessment by a health professional is also a very important part of diagnosing asthma and will include listening to the chest with a stethoscope, assessing vital signs and looking for other clinical signs of asthma.4
Treatment of Asthma
Management or treatment of asthma involves reducing the frequency and severity of asthma attacks. Reducing exposure to identified triggers that may cause an asthma attack in a specific individual may help, but inhaled medications (commonly known as puffers) or sometimes oral medications (tablets) often help to reduce the airway inflammation that results from exposure to a trigger.
There are 2 main types of using inhaled medication to treat asthma:
Relievers or Rescuers
Relievers or rescuers for asthma are usually a short-acting beta agonist (SABA) inhaled medications that help to reduce airway muscle spasm (bronchospasm) during an asthma attack. Common relievers or rescuers include:
- albuterol or salbutamol (Ventolin)
- terbutaline (Bricanyl)
- pirbuterol (Maxair)
Another form of inhaled medication that acts as an anticholinergic and also reduces bronchospasm is called ipratropium (Atrovent, Apovent or Aerovent) and can be used as a reliever or rescuer if the above SABAs are not well tolerated.
Preventers or Controllers
Preventers or controllers for asthma are usually longer acting inhaled medications that either are made up by a inhaled corticosteroid (ICS) or long-acting beta agonist (LABA).There are also combined inhaled medications that include a long-acting beta agonist (LABA) and an inhaled corticosteroid (ICS). These medications act by reducing inflammation and bronchospasm of the airways over a longer period, and usually are administered twice a day (morning and night). Common preventers include:
ICS
- beclometasone (Qvar)
- budesonide (Pulmicort)
- fluticasone (Flixotide or Flovent)
- ciclesonide (Alvesco)
- mometasone (Asmanex)
- triamcinolone (Azmacort)
LABA
- salmeterol (Serevent)
- eformoterol (Foradile or Oxis)
Combined
- budesonide and eformoterol (Symbicort)
- fluticasone and salmeterol (Seretide or Advair)
Other medications used as preventers more commonly in children include montelukast (Singulair or Accolate) and nedocromil sodium (Tilade or Intal) which both reduce airway inflammation.
Occasionally oral corticosteroids (tablets) may be required to treat moderate to severe asthma attacks that will require a short course of higher dose steroids that help to reduce airway inflammation. Some common oral steroids used to treat asthma include Prednisone, Redipred, Decadron, Deltasone, Medrol, Orapred, Pediapred and a variety of others.5
Other treatments are sometimes used including treating underlying upper respiratory tract infections or allergic (atopic) conditions.
There are also a range of complementary or alternative therapies that are used by long-term asthma sufferers that can sometimes provide some improvement in symptoms. These include breathing techniques, yoga, vitamins and supplements, acupuncture, homeopathy and traditional chinese medicine.
If you think you may have any symptoms of asthma please see a qualified medical practitioner who will assist you in diagnosis and appropriate treatment. If you are suffering from any severe symptoms of asthma including extreme shortness of breath, difficulty speaking or collapse you should seek urgent medical assistance.
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References for Asthma Resources
1. Wikipedia. "Asthma". Retrieved 28 January 2011.
2. Neil K. Kaneshiro, MD. "Bronchial Asthma". PubMed Health. Retrieved 14 July 2010.
3. George C. Schiffman, MD, FCCP. "Causes of Asthma". eMedicineHealth. Retrieved 27 March 2009.
4. Roger W. Harms, M.D. "Symptoms of Asthma". Mayo Clinic. Retrieved 27 May 2010.
5. WebMD. "Causes and Treatment of Asthma". Retrieved 30 March 2009.
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