There are two types of obstructive lung diseases, asthma and COPD. Asthma is characterised by normal lung function in most asthmatic people when not having an asthma attack, whereas people with COPD never have a normal lung function, they have chronic obstruction. Neither asthma nor COPD are clearly defined diseases, they represent two different groups of diseases in which the symptoms may vary.
In the case of asthma, there is usually a great sensitivity to airborne substances in the environment which as they are inhaled, give rise to irritation and asthma symptoms such as cough, whistling breathing sounds (wheezing) and shortness of breath. People with COPD may also experience problems when they inhale irritating substances, but often not to the same degree as the asthmatics. Asthma often first appears in childhood or in adolescence (but may in a few cases start at adult age) and often appears together with allergies to pollen, pets, dust mites and/or other allergy provoking substances and allergens. Asthma often makes its debut with acute problems, and treatment often leads to most asthmatics being able to live their lives free, or almost free from symptoms. Asthmatic people have, just like people with COPD, periods of deterioration, which may be caused by infections, exposure to allergies and other factors. Asthma does not lead to emphysema or respiratory failure and death from asthma is rare unless the asthma is uncontrolled.
People with COPD are often affected by the disease later in life, the disease is uncommon in people under the age of 45, and there is no connection between allergies and COPD. The disease makes its debut slowly, and people with COPD usually are able to "get used" to having symptoms. They might not think much about their clinical state slowly getting worse and that they are more and more out of breath from even a little physical effort. The connection between COPD and that the person during later years has suffered from longer lasting airway infection is not always observed. In those who suffer from the most severe COPD, respiratory failure is developed which often implies limitations of daily life and, apart from previously mentioned symptoms, an abnormal tiredness that remains despite resting.
In the case of other types of lung diseases that comes with reduced ventilation the results of spirometry are often not of an obstructive nature, but restrictive. A restrictive lung function reduction signifies that the lungs are "too small" in general. This type of lung function reduction is observed in pulmonary fibrosis, different diseases coming from inhalation of inorganic materials (silicosis, asbestos among others), neurological diseases, etc.
UK/GEN/15/0058a Date of preparation: December 2015