Chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is an umbrella term for a group of respiratory tract diseases that are characterised by airflow obstruction or limitation. It is usually caused by tobacco smoking. more...
Conditions included in this umbrella term are:
- chronic bronchitis
COPD is also known as CORD, COAD, COLD which respectively stand for chronic obstructive respiratory, airways, or lung disease. COPD has been referred to as CAL which stands for chronic airway limitation.
COPD is a chronic, progressive disorder related to tobacco abuse and characterized by airways obstruction (FEV1 <80% predicted and FEV1 / VC ratio <70%).
The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as "a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and associated with abnormal inflammatory response of the lungs to noxious particles or gases."
The main risk factor in the development of COPD is smoking. Approximately 15% of all chronic smokers will develop the disease. In susceptible people, this causes chronic inflammation of the bronchi and eventual airway obstruction. Other etiologies include alpha 1-antitrypsin deficiency (augmented by smoking), byssinosis, and idiopathic disease.
Among people over 70 who have never smoked, women make up 85 percent of those with COPD. This appears to be tied to decreases in estrogen as women age. Female mice that had their ovaries removed to deprive them of estrogen lost 45 percent of their working alveoli from their lungs. Upon receiving estrogen, the mice recovered full lung function. Two proteins that are activated by estrogen play distinct roles in breathing. One protein builds new alveoli, the other stimulates the alveoli to expel carbon dioxide. Loss of estrogen hampered both functions in the test mice. (Massaro & Massaro, 2004).
COPD is a progressive disease. Obstructive changes in spirometry and decreases in diffusion capacity are typically seen before symptoms occur. Early signs and symptoms are shortness of breath on exertion, recurrent respiratory infections or a morning cough. As the disease continues, the symptoms are seen with increased frequency and severity. In the late stages, the patient often experiences severe cough, constant wheezing, and shortness of breath with minimal exertion or rest. At this late stage, progression to respiratory failure and death is common. Progression is typically caused by the patient's continued exposure to tobacco smoke. Although medications often decrease symptoms, it is not believed that they prevent the progression if the patient continues to smoke.
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