Asthma

Asthma is a disease in which the patient will wheeze. However not everyone who wheezes has asthma and this often presents some challenges to the physician, especially in the first year or so of life. Isolated wheezing can occur with minor airways obstruction, for example when “something goes down the wrong way” and along with the spluttering goes a short lived wheeze. You can also get a wheeze with chest infections such as bronchitis but in both of these scenarios, the external stimulus to wheezing is temporary, and once it has been removed the wheeze disappears. In people with asthma, something else is going on which causes them to wheeze with far more minor stimulations and this can be associated with shortness of breath, waking up at night short of breath and in some cases can even be life-threatening.

So what happens in asthma? First a quick anatomy lesson, inhaled air enters the lungs via your windpipe that then divides into two main branches or bronchi with one to the right lung and one to the left lung. These main bronchi continue to divide into smaller and smaller tubes finally ending in what we term the alveolus, which is where the business end of oxygen and carbon dioxide transfer happens. But it’s in the smaller tubes, or airways, where asthma has its pathological effects. The walls of these small tubes are encircled by a muscle that helps control the diameter of the tube and in asthma this muscle tends to get thicker and more reactive to normal stimuli. The lining of these fine tubes has a special membrane which secretes a watery mucous to trap any dust particles. These dust particles are then gently wafted towards the outside by microscopic cilia (which are like tiny hairs) to be coughed up or swallowed depending on the quantity produced. In asthma, this inner surface becomes inflamed and thick and in combination with the thickened muscular layer causes the overall inner diameter of the tube to be narrower in the resting state! Also the mucous produced tends to become thicker and stickier and more difficult to push towards the outside.

It's important to understand what is happening in asthma so that you can understand why there are two arms to the current approach to managing and controlling the problem. Doctors talk about 'relievers' which are aimed at reducing the spasm in those circular muscles and help open up the airways during an asthma attack. But if the underlying inflammation and thickening are not also targeted, then the disease will not be fully controlled and hence the second string to the medical bow are the 'preventers'. Preventers are generally inhaled steroids and designed to counteract the inflammation and thickening of the airways. It is vitally important that all patients with asthma, or parents of children with asthma, have a basic understanding of what is happening with the disease and remain committed to good preventative measures. The cornerstone of good preventative measures is correct use of appropriate inhalers and to know what to do in the case of unexpected deterioration during an asthma attack. It is also important that people with asthma do not smoke and avoid all exposure to tobacco smoke and toxic fumes.

Asthma does tend to run in families, it is associated with skin conditions such as eczema and dermatitis and people with asthma do tend to suffer more from allergies. When diagnosing a patient who presents with a wheezy cough, all of the above mentioned factors need to be taken into account and investigated appropriately. If the diagnosis of asthma is confirmed, then all asthma patients, their families and schools should be given an asthma action plan so that their asthma can be managed effectively and there is a plan for emergency situations.

Finally, everyone, including people with asthma, can do a great deal to improve fitness and health by being fit and active, keeping to a healthy weight, not smoking and getting an annual flu shot.

HBF Family Doctor Duncan Jefferson.

HBF Health Funds, the largest health insurance provider in Western Australia.