COPD

1. CChhrroonniicc Bronchitis
Chronic bronchitis
Chronic Bronchitis is a respiratory condition that involves inflammation of the bronchial tubes
(medium-sized airways) and bronchioles (the smaller branches of the bronchi) resulting in
excessive secretions of mucus and tissue swelling that reduces the diameter of the bronchial
tubes, making it progressively more difficult to breath. It leads to persistent coughing and
production of sputum (phlegm) and mucus on a daily basis for at least three months per year,
two years in a row. In the majority of patients both CB and emphysema co-exist, usually in
heavy cigarette smokers.
Aetiology and prevalence
Atmospheric pollution and occupational dust exposure are minor aetiological factors in
chronic bronchitis and the dominant causal agent is cigarette smoke. Smoking also causes
emphysema.

2. Mechanism of airflow obstruction
In chronic bronchitis the fundamental cause of reduced ventilatory capacity and breathlessness
is the limitation of expiratory airflow. The disease is caused by an interaction between noxious
inhaled agents and host factors, such as genetic predisposition or respiratory infections which
cause injury or irritation to the respiratory epithelium of the walls and lumen of the bronchi
and bronchioles. Chronic inflammation, edema, temporary bronchospasm, and increased
production of mucus by goblet cells are the result. As a consequence, airflow into and out of
the lungs is reduced, sometimes to a dramatic degree.

3. Clinical features
Chronic bronchitis develops over many years and patients are rarely symptomatic before
middle age. Symptoms are initially minor, perhaps a morning cough productive of a little
sputum. The sputum may be clear, yellowish, or greenish depending on bacterial infection, and
sometimes tinged with blood if small blood vessels are ruptured due to constant coughing.
Initially breathlessness is on exertion but exercise capacity progressively and slowly
deteriorates and eventually patients become respiratory cripples distressed even at rest.
Patients with predominant bronchitis are prone to periodic infections. Eventually patients with
chronic bronchitis develop severe hypoxia and other complications.

4. CChhrroonniicc BBrroonncchhiittiiss
Management
Restoration of normal function is not possible in chronic bronchitis. The aim of therapy must
therefore be to reduce disability by tackling the interrelated problems of airways obstruction,
recurrent infections, breathlessness, hypoxia and poor exercise tolerance. Factors aggravating
chronic bronchitis, particularly cigarette smoking, must be withdrawn.
Oxygen therapy
During acute exacerbation of chronic bronchitis, O2 therapy is necessary to avoid death from
hypoxia. Studies suggest that long-term controlled O2 therapy can benefit patients with severe
airways obstruction who have severe hypoxia and who refrain from smoking cigarettes. It is
necessary to administer O2 virtually continuously, including during sleep. The administration
of continuous O2 presents considerable practical and financial difficulties.
Cessation of cigarette smoking
Tobacco smoke damages the bronchial tree and produces airflow limitation by a number of
different actions. Smoke impairs mucociliary clearance and causes bronchial smooth muscle to
contract by stimulating receptors and provoking the release of inflammatory mediators. In
addition, smoke increases mucus production and causes mucous gland hypertrophy. Smokers
are predisposed to bronchial infection and consequent inflammation. It is therefore not
surprising that chronic bronchitis and emphysema are found in 15% of middle-aged males who
smoke moderately or heavily but are rare in non-smokers, and that deaths from bronchitis
increase with the amount smoked.
If patients with chronic bronchitis and emphysema stop smoking, the rate of decline in
pulmonary function is reduced to that of non-smokers. If patients stop smoking early in their
disease there is improvement in pulmonary function.
Diagnosing Chronic Bronchitis
Physicians diagnose chronic bronchitis by using a combination of medical history, physical exam, and
diagnostic tests. A history of a daily cough that lasts at least three months, especially if has occurred two years
in a row, fits the criteria for a clinical diagnosis of chronic bronchitis. A history of smoking and/or working
with noxious chemicals is also very relevant. The physical examination usually includes listening for wheezing,
determining if there is a prolongation of exhalation, and looking for evidence of cyanosis, which are all signs of
airflow obstruction. A sputum sample showing neutrophil granulocytes (inflammatory white blood cells) and a
positive culture for pathogenic microorganisms such as Streptococcal species are also indications that the
patient might have chronic bronchitis. However, for expectorated sputum samples to be considered valid,
conventional wisdom is that there should be fewer than 10 squamous cells and more than 25 white blood cells
per high-power microscopic field.
A chest X-ray is often taken if bronchitis is suspected to help rule out other lung conditions such as pneumonia,
tuberculosis, or bronchial obstructions.