COPD is a chronic, irreversible obstruction of air flow. The airflow limitation is usually progressive and is believed to reflect an abnormal inflammatory response of the lungs to noxious particles or gases.it is characterized by:
• Airway inflammation
• Reduction in maximum expiratory flow
• An episodic exacerbations of airflow obstruction
• Progressive decline of lung function as demonstrated by forced expiratory volume (FEV).
• Dyspnea(shortness of breath)
• a persistent cough
• sputum or mucus production
• wheezing
• chest tightness and
• Tiredness.
Risk factor:
Smoking is the major risk factor for COPD and often a consequence of habitual cigarette smoking , but 15% patients are non-smokers. Heavy tobacco exposure is a common underlying theme in this disorder. COPD is the fourth leading cause of death in adult population.
Diagnosis:
The diagnosis of COPD should be considered in anyone who has dyspnea, chronic cough or sputum production, and/or a history of exposure to risk factors for the disease such as regular tobacco smoking. No single symptom or sign can adequately confirm or exclude the diagnosis of COPD, although COPD is uncommon under the age of 40 years
Disorders associated with COPD:
• Chronic bronchitis
• Bronchiectasis
• Emphysema
• Small airway disease(bronchiolitis)
Emphysema:
Emphysema is a chronic obstructive air way disease characterized by permanent enlargement of airspaces distal to terminal bronchioles. Histologically there is thinning and destruction of alveolar walls. Terminal and respiratory bronchioles may be deformed due to loss of septa that help tether the structure in parenchyma. With loss of elastic tissue in alveolar septa there is loss of traction in small airways so they tend to collapse during expiration. In addition to alveolar loss number of alveolar capillaries also diminishes, which is an important cause of chronic airway obstruction. Individuals with pure emphysema are characterized as “pink puffers”.
ANATOMIC SITE: acinus
PATHOLOGICAL CHANGES: air space enlargement, wall destruction
ETIOLOGY: tobacco smoke
SIGNS/SYMPTOMS: dyspnea
Chronic bronchitis:
Chronic bronchitis is defined as persistent productive cough for at least 3 consecutive months or 2 consecutive years. The histological feature of chronic bronchitis is the enlargement of the mucus secreting glands present in mucosal lining of large airways. It is characterized by goblet cell metaplasia, mucus plugging, inflammation and fibrosis. In severe cases there is complete obliteration of the lumen due to fibrosis (bronchiolitis obliteration). Chronic obstructive component largely results from small airway disease and co-existent emphysema.
ANATOMIC SITE: bronchus
PATHOLOGICAL CHANGES: mucus gland hyperplasia, hyper secretion
ETIOLOGY: tobacco smoke, air pollutants
SIGNS/SYMPTOMS: Cough sputum production.
Small airway disease:
ANATOMIC SITE: bronchiole
PATHOLOGICAL CHANGES: inflammatory scarring, obliteration of bronchioles
ETIOLOGY: tobacco smoke, air pollution
SIGNS/SYMPTOMS: cough, dyspnea
BROCHIECTASIS:
Bronchiectasis is a condition in which damage to the airways causes them to widen and become flabby and scarred. In bronchiectasis, your airways slowly lose their ability to clear out mucus. When mucus can\'t be cleared, it builds up and creates an environment in which bacteria can grow. This leads to repeated, serious lung infections. Each infection causes more damage to your airways. Over time, the airways lose their ability to move air in and out.
ANATOMIC CHANGES: bronchus
PATHOLOGICAL CHANGES: airway dilation and scarring
ETIOLOGY: persistent and severe infection
SIGNS/SYMPTOMS: cough, purulent sputum, fever
Treatment:
Bronchodilators:
Bronchodilators are medicines that relax smooth muscle around the airways, increasing the caliber of the airways and improving air flow. They can reduce the symptoms of shortness of breath, wheeze and exercise limitation, resulting in an improved quality of life for people with COPD.
β2 agonists:
β2 agonists stimulate β2 receptors on airway smooth muscles, causing them to relax. Salbutamol and terbutaline are widely used short acting β2 agonists and provide rapid relief of COPD symptoms. Long acting β2 agonists (LABAs) such as salmeterol and formoterol are used as maintenance therapy and lead to improved airflow, exercise capacity, and quality of life.
Anti-cholinergic:
Anticholinergic drugs cause airway smooth muscles to relax by blocking stimulation from cholinergic nerves. Ipratropium is the most widely prescribed short acting anticholinergic drug. Like short-acting β2 agonists, short-acting anti-cholinergic provide rapid relief of COPD symptoms and a combination of the two is commonly used for a greater bronchodilator effect. Tiotropium is the most commonly prescribed long-acting anticholinergic drug in COPD.
Other medications:
Theophylline is a bronchodilator and phosphodiesterase inhibitor that in high doses can reduce symptoms for some people who have COPD.
Supplemental oxygen:
Supplemental oxygen can be given to people with COPD who have low oxygen levels in the body. Oxygen is provided from an oxygen cylinder or an oxygen concentrator and delivered to a person through tubing via a nasal cannula or oxygen mask. Supplemental oxygen does not greatly improve shortness of breath but can allow people with COPD and low oxygen levels to do more exercise and household activity. Long-term oxygen therapy for at least 16 hours a day can improve the quality of life and survival for people with COPD.
Surgery:
Surgery is sometimes helpful for COPD in selected cases. A bullectomy is the surgical removal of a bulla, a large air-filled space that can squash the surrounding, more normal lung and Lung volume reduction surgery is done. Lung transplantation is sometimes performed for severe COPD, particularly in younger individuals.
Diagnostic tests:
• Chest x-ray the classic signs of COPD are over expanded lung (hyperinflation), a flattened diaphragm, increased retrosternal airspace, and bullae. It can be useful to help exclude other lung diseases, such as pneumonia, pulmonary edema or a pneumothorax
• Pulmonary function tests with measurements of lung volumes and gas transfer may also show hyperinflation and can discriminate between COPD with emphysema and COPD without emphysema.
• A high-resolution computed tomography scan of the chest may show the distribution of emphysema throughout the lungs and can also be useful to exclude other lung diseases.
Management strategies:
• Smoking cessation,
• vaccinations
• Rehabilitation, and drug therapy (often using inhalers)
• Some patients go on to require long-term oxygen therapy or lung transplantation
By
Fatima Fayyaz
DP01083-203
Doctor of Pharmacy
University of Lahore
