Asthma (Part 2 of 3)

How is asthma diagnosed?

Sometimes symptoms are typical, and the diagnosis is easily made by a doctor. If there is doubt then some simple tests may be arranged. A peak flow meter is commonly used to help confirm that symptoms are due to asthma (see below). Sometimes a test called spirometry may be done to confirm the diagnosis. This involves breathing into a machine that measures the rate and volume of airflow in and out of your lungs.

What is the the peak flow meter?

This is a small device that you blow into. A doctor or nurse will show you how. It measures the speed of air that you can blow out of your lungs. No matter how strong you are, if your airways are narrowed, your peak flow reading will be lower than expected for your age, size, and sex. If you have untreated asthma, then you will normally have low and variable peak flow readings. Also, peak flow readings in the morning are usually lower than the evening if you have asthma.

You may be asked to keep a diary over two weeks or so of peak flow readings. Asthma is usually confirmed if you have low and variable peak flow readings over several days. Peak flow readings improve when the narrowed airways are opened up with treatment. Regular peak flow readings can be used to help assess how well treatment is working.

What are the treatments for asthma?

For most people with asthma, most of the symptoms can be prevented with treatment. So, you are able to get on with normal life, school, work, sport, etc.

Inhalers
Most people with asthma are treated with inhalers. Inhalers deliver a small dose of drug directly to the airways. The dose is enough to treat the airways. However, the amount of drug that gets into the rest of your body is small so side-effects are unlikely, or minor. There are various inhaler devices made by different companies. Different ones suit different people. A doctor or nurse will advise on the different types. See a separate leaflet called ‘Asthma - Inhalers‘.

Inhalers can be grouped into ‘relievers’, ‘preventers’ and ‘long acting bronchodilators’.

• A reliever inhaler is taken ‘as required’ to ease symptoms. The drug in a reliever inhaler relaxes the muscle in the airways. This makes the airways open wider, and symptoms usually quickly ease. These drugs are also called ‘bronchodilators’ as they dilate (widen) the bronchi (airways). There are several different reliever drugs. For example, salbutamol and terbutaline. These come in various brands made by different companies. If you only have symptoms every ‘now and then’, then the occasional use of a reliever inhaler may be all that you need. However, if you need a reliever inhaler three times a week or more to ease symptoms, a preventer inhaler is usually advised.
  
• A preventer inhaler is taken every day to prevent symptoms from developing. The drug commonly used in preventer inhalers is a steroid. There are various brands. Steroids work by reducing the inflammation in the airways. When the inflammation has gone, the airways are much less likely to become narrow and cause symptoms. It takes 7-14 days for the steroid in a preventer inhaler to build up it’s effect. Therefore, it will not give any immediate relief of symptoms. However, after a week or so of treatment, the symptoms have often gone, or are much reduced. It can take up to six weeks for maximum benefit. You should then not need to use a reliever inhaler very often, (if at all).
  
• A long acting bronchodilator may be advised in addition to a steroid inhaler. One may be needed if symptoms are not fully controlled by the steroid inhaler alone. The drugs in these inhalers work in a similar way to ‘relievers’, but work for up to 12 hours after taking each dose. They include salmeterol and formoterol. (Some brands of inhaler contain a steroid plus a long acting bronchodilator for convenience.)

Tablets to open up the airways
Most people do not need tablets as inhalers usually work well. However, in some cases a tablet (or in liquid form for children) is prescribed in addition to inhalers if symptoms are not fully eased by inhalers alone. Some young children use liquid medication instead of inhalers.

Steroid tablets
A short course of steroid tablets (such as prednisolone) is sometimes needed to ease a severe or prolonged attack of asthma. Steroid tablets are good at reducing the inflammation in the airways. For example, a severe attack may occur if you have a cold or chest infection.

Some people worry about taking steroid tablets. However, a short course of steroid tablets (for a week or so) usually works very well, and is unlikely to cause side-effects. Most of the side-effects caused by steroid tablets occur if you take them for a long time (more than several months), or if you take frequent short courses of high doses.