Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the lungs, in which the airways become blocked, causing cough with mucus, wheezing, and shortness of breath.
Symptoms are most evident when significant lung damage has already occurred, and usually worsen with time. Although COPD has no cure, proper medication and lifestyle changes can reduce some of its symptoms.
The causes of COPD are not yet fully understood. However, long-term exposure to lung irritants, particularly cigarette smoke, is known to damage the lungs, as well as the airways. The disease is more common in middle-aged or older people, although it can also affect those under 40.
Types of COPD
There are two main types of COPD. One of them is a condition called emphysema, a lung disease in which the alveoli — the tiny air sacs where oxygen is exchanged in the lungs — become damaged and lose elasticity, causing airflow in the lungs to decrease.
The other type is chronic bronchitis, which leads the airways to become inflamed and enlarged, causing thick mucus to build up and block the narrowed airways.
Causes of COPD
Tobacco smoking is the main cause of COPD in developed countries, while in developing countries the disease is often caused by exposure to fumes from cooking oils or heating in poorly ventilated houses, as well as tobacco use. 85–90% of all COPD cases are caused by cigarette smoking.
Other causes include second-hand smoke, such as exposure to tobacco smoke exhaled by others or smoke from the burning end of cigarettes, exposure to chemical fumes, dust, or air pollutants.
In rare cases, mutations in the SERPINA1 gene, which provides instructions to make a protein called alpha-1-antitrypsin (AAT), may lead to the onset of COPD. AAT is produced in the liver to protect the lungs from harmful substances, such as cigarette smoke. A deficiency in this protein causes the lungs to become unprotected and increasingly damaged.
In rare cases, people with asthma, a chronic lung disease that causes the airways to become inflamed and narrower, also may be at risk of developing COPD when their disease is poorly managed.
Symptoms of COPD
Shortness of breath, even with non-strenuous exercise, is one of the hallmark symptoms of COPD. This is due to an airflow blockage, which is caused by inflammation and excessive mucus production in the airways. Shortness of breath also causes levels of oxygen in the blood to drop, which may lead some patients to develop cyanosis, or blueness, of the lips or fingernail beds.
Inflammation and narrowing of the airways may lead patients to experience wheezing while breathing. Persistent cough associated with excessive mucus production also is frequent.
Some people may experience flare-ups or sudden episodes of symptom worsening, that can last for days.
Other possible COPD symptoms at more advanced stages include lack of energy, unintentional weight loss, swelling in ankles, feet, or legs.
Diagnosis of COPD
COPD diagnosis usually involves a complete assessment of a patient’s medical and family history, complemented by a series of tests, particularly lung function tests and others that may help rule out other conditions that cause similar symptoms.
Spirometry lung function tests can be used to measure the amount of air one is able to breathe in and out, as well as breathing speed. These tests can be used not only to identify COPD but also to monitor and track its progression.
Imaging tests, including chest X-rays and computed tomography scans, and blood tests may be used to determine whether another condition, such as asthma, AAT deficiency, or heart failure, is causing the symptoms.
Treating COPD
Treatments for COPD can control symptoms, slow disease progression, reduce the risk of flare-ups, and improve patients’ ability to exercise.
The most important step in COPD treatment is to quit smoking. Patients usually are told to also avoid second-hand smoke exposure and other air pollutants at home and at work.
Most symptoms are managed with medications. Cough and shortness of breath may be eased with bronchodilators, which act by relaxing and opening up the airways, making it easier for patients to breathe.
Oral and inhaled corticosteroids also may be used to reduce airway inflammation and help prevent COPD flare-ups.
Other treatments include antibiotics to treat respiratory infections that can be more frequent among COPD patients, and oxygen therapy to improve blood oxygen levels.
Some patients may undergo pulmonary rehabilitation, a customized treatment program encompassing nutritional and psychological counseling that educates patients and helps them adopt strategies to breathe better and preserve their energy, ultimately improving their quality of life.
Surgery may be an option for some patients who have severe symptoms and fail to respond to pharmacological treatments. Surgical procedures used to treat COPD include lung volume reduction surgery (removal of small sections of damaged lung tissue), lung transplant, and bullectomy (removal of large air spaces that arise in the lungs when the walls of the alveoli are destroyed).