Respiratory disease overview: an often undiagnosed condition

Diseases of the respiratory system are relatively common. Many viruses are spread by droplets in the air, and find a ready home in our throat and lungs. Colds and flu are the result. More serious infections such as pneumonia can occur and may be life-threatening in the very young and very old.

This review will focus on two common respiratory diseases: asthma and chronic obstructive airways disease (COPD).

COPD is almost exclusively a disease of smokers and begins to manifest itself in middle age. Meanwhile asthma often, though not exclusively, begins in childhood. It occurs when some trigger causes the larger airways to narrow down and tighten.

Lung disease is the third most common reason for acute hospital admission in Ireland. About one in seven Irish people have undiagnosed lung disease; for people who are aged 60 and over and who have a history of smoking, the level of undiagnosed disease is doubled.

COPD is an umbrella term for two diseases: chronic bronchitis (inflammation and narrowing of the airways) and emphysema (weakening of the structure of the lung). A progressive disease most often linked with smoking, it causes chronic breathlessness that can lead to severe disability.

Essentially, COPD limits the flow of air leading to excess air being trapped in the lungs after a person has breathed out. Known as “airtrapping” it is the main cause of breathlessness in a person with COPD. There are 12,000 confirmed admissions to hospital with COPD in Ireland every year and approximately 100,000 diagnosed with the condition, but the number of those undiagnosed is estimated to be twice that of those who are diagnosed.

During an Asthma attack the muscles in the walls of the breathing tubes tighten and this causes a reduction in the amount of air moving in and out of the lungs.

Ireland has the fourth highest prevalence of asthma in the world. One in five children and 1 in 10 adults here have the disease; this equates to almost 600,000 asthma sufferers in Ireland.

CAUSES, SIGNS AND SYMPTOMS

COPD consists of two overlapping conditions. The first is chronic bronchitis where the breathing tubes produce excessive amounts of mucus. This is often known as a smoker’s cough. Emphysema is where the interstitial part of the lung (the tissue and space around the air sacs of the lungs) is destroyed over years, usually by smoking. There is less surface area for oxygen to get across into the bloodstream leading to shortness of breath which can go on for years.

Apart from smoking another cause of COPD is deficiency of an enzyme called Alpha-1 antitrypsin. It is a protein which protects the lungs and people with lower than normal amounts of this protein are at an increased risk of developing COPD

People with COPD are prone to suffering acute exacerbations of the condition. When this happens theyexperience a rapid worsening of symptoms such as severe breathlessness, wheeze, nasal congestion and cough. Infected mucus in the lungs leads to a huge increase in the production of dirty sputum.

When your doctor examines you he may pick up signs of poor entry of air in to the lungs or you may have signs of an acute chest infection. COPD can be definitively diagnosed by undergoing pulmonary function tests, which show a characteristic pattern if you have the disease.

The following is a handy checklist for COPD.

1. Do you cough several times most days?

2. Do you bring up phlegm or mucus most days?

3. Do you get out of breath more easily than others your age?

4. Are you over 40 years old?

5. Are you a current smoker or an ex-smoker?

If you answer yes to three or more of these questions, then it’s worth asking your doctor if you might have the condition.

The exact cause of Asthma remains unknown. Sometimes it affects several family members. If you have parents or brothers and sisters with asthma or allergies such as eczema or hay fever, you are more likely to develop it.

Adults sometimes develop asthma after a respiratory tract infection. Whatever the trigger, the airways become over-sensitive and react to cold and dust, which normally would not cause a problem. As a result the muscles around the wall of the airway tighten up, making it difficult for air to flow in or out. The lining of the airways then gets swollen and sticky mucus is produced, clogging up the breathing passages.

The symptoms of asthma are wheeze, shortness of breath and coughing. Chest pain may occur. During an acute exacerbation these symptoms worsen and the person with asthma may find it difficult to speak.

Your GP will be able to diagnose asthma based on the pattern of your symptoms and whether you have a family history of the disease. An examination of the chest may reveal signs of the condition and your doctor will also ask you to blow into a peak flow meter. This is a hand -held gadget which gives an accurate measurement of how fast you can force air out of the lungs.

TREATMENT AND PREVENTION

The best way to avoid COPD is never to smoke. If you have started smoking then the sooner you stop the least damage will be done to your lungs.

There are a number of treatments available for COPD but unfortunately, no medical treatment has been shown to reverse structural damage already done to the lungs. But proper treatment does relieve symptoms, improves quality of life, reduces frequency of exacerbations and the need for hospitalisation.

Different types of inhalers are used to treat COPD. In addition you may be put on oral medication. During an exacerbation, your doctor may prescribe antibiotics and steroids to deal with the worsening of symptoms.

Asthma is treated using inhalers and drugs. There are two main types of inhaler: “preventers” and “relievers”. The preventer contains an anti-inflammatory drug that soothes the breathing tubes making them less irritable. Used on a regular basis, it can make a huge difference to the frequency of asthma attacks.

The other type, containing a bronchodilator, is used to relieve an asthma attack by relaxing the muscles in the breathing tubes.

During an asthma exacerbation, you may require drugs to be delivered by a nebuliser, an electronic device that delivers the medication in an aerosol mist for better delivery and absorption. And if this doesn’t quieten the attack, intravenous and subcutaneous injections of steroids and other drugs may be required.

If you need to be nebulised on a regular basis, this is a sign that your asthma is poorly controlled. It also means you are more likely to suffer a life-threatening attack in the future.

Other signs of poor control include coughing and shortness of breath occurring more than twice a week; being woken at night by symptoms more than once a week; experiencing some limits on your ability to carry out normal daily activities; and having to use additional reliever doses of inhaler on more than two days per week.

For the most effective asthma treatment, work out a treatment plan with your doctor. This involves routinely tracking symptoms and measuring how well your lungs are working.

The best way to track symptoms is to use an asthma diary. It allows you record whether you are short of breath or wheezing; note any sleep disturbance due to asthma symptoms; chest tightness; asthma symptoms during exercise; and any changes in the colour of your phlegm.

In addition, it facilitates a record of how many puffs of rescue inhaler you use as well as recording disruptions to work or school activities.

For those with allergies, avoiding them where possible will help reduce the number of acute attacks.

USEFUL RESOURCES

The Asthma Society of Ireland: asthma.ie,  Helpline 1850 44 54 64

The Irish Thoracic Society has a website for people with COPD. irishthoracicsociety.com/lung-disease/copd

Asthma UK: asthma.org.uk

The asthma society of Canada: www.asthma.ca

Dr Muiris Houston is a specialist in general practice and occupational medicine and a medical education consultant