Chronic Bronchitis

Chronic bronchitis is a form of chronic obstructive pulmonary disease. It's marked by excessive production of tracheobronchial mucus that is sufficient to cause a cough for at least 3 months each year for 2 consecutive years.

The severity of the disease is linked to the amount of cigarette smoke or other pollutants inhaled and the duration of the inhalation. A respiratory tract infection typically exacerbates the cough and related symptoms. However, few patients with chronic bronchitis develop significant airway obstruction. About 20% of men have chronic bronchitis.

Causes and pathophysiology

Cigarette smoking is the most common cause of chronic bronchitis. Some studies suggest a genetic predisposition to the disease as well.

The disease is directly correlated to heavy pollution and is more prevalent in people exposed to organic or inorganic dusts and noxious gases. Children of parents who smoke are at higher risk for respiratory tract infections that can lead to chronic bronchitis.

Chronic bronchitis results in hypertrophy and hyperplasia of the bronchial mucous glands, increased goblet cells, ciliary damage, squamous metaplasia of the columnar epithelium, and chronic leukocytic and lymphocytic infiltration of bronchial walls. Additional effects include widespread inflammation, airway narrowing, and mucus within the airways- all producing resistance in the small airways and, in turn, a severe ventilation-perfusion imbalance.

Signs and Symptoms

• Cough that produces mucus, which may be blood streaked
• Shortness of breath aggravated by exertion or mild activity
• Frequent respiratory infections that worsen symptoms
• Wheezing
• Fatigue
• Ankle, foot, and leg swelling that affects both sides
• Headaches

Diagnostic tests

Chest X-rays may show hyperinflation and increased bronchovascular markings.

Pulmonary function tests demonstrate increased residual volume, decreased vital capacity and forced expiratory flow, and normal static compliance and diffusing capacity.

Arterial blood gas (ABG) analysis displays decreased partial pressure of arterial oxygen and normal or increased partial pressure of arterial carbon dioxide.

Sputum culture may reveal many microorganisms and neutrophils.

Electrocardiography may reveal atrial arrhythmias, peaked P waves in leads II, III, and aVF and, occasionally, right ventricular hypertrophy.

Treatment

The most effective treatment is for the patient to stop smoking and to avoid air pollutants as much as possible. Antibiotics can be used to treat recurring infections. Bronchodilators may relieve bronchospasm and facilitate mucus clearance. Adequate fluid intake is essential, and chest physiotherapy may be needed to mobilize secretions. Ultrasonic or mechanical nebulizer treatments may help to loosen and mobilize secretions. Occasionally, a patient responds to corticosteroid therapy. Diuretics may be used to treat edema, and oxygen may be necessary to treat hypoxia.

Prevention

Early recognition and treatment may prevent the progression of the disease in people who also stop smoking.