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"Simple chronic bronchitis" refers to a productive cough for at least 3 months of the year for 2 consecutive years. It af-fects 10 to 25 per cent of the adult population. Cough with sputum production is more common in men than in women and more common in persons over the age of 40 than in younger in-dividuals. All forms of chronic bronchitis are strongly linked to cigarette smoking. Thus, a large proportion of cigarette smok-ers, particularly those over age 45, fit the diagnostic criteria for simple chronic bronchitis. Some occupations (e. g., those involving dust, handling grain, and mining) are associated with an abnormally high incidence of chronic bronchitis, even after statistics are corrected for smoking habits. Few individu-als with simple chronic bronchits consult a physician, and then the visit is usually prompted by acute or recurrent respiratory tract infections or wheezing in addition to chronic cough. Chronic asthmatic bronchitis tends to develop in elderly indi-viduals, most commonly, they are smokers.
Three direct effects of inhaling bronchial irritants cause chronic bronchitis:1. stimulation of mucus secretion in the air-ways, 2. impaired mucus clearance due in part to interference with ciliary activity, and 3. lowered resistance to bronchopul-monary infection because of disturbed alveolar macrophage function. Cough develops owing to accumulation of secretions. As a result of bacterial colonization by organisms usually found in the nasopharynx, normally sterile bronchi now harbor or-ganisms.
Although cigarette smoking is the most important of the identifiable causal factors, not all smokers experience mucus hypersecretion, and no more than 15 to 20 per cent develop airflow obstruction. Little is known about the reasons for the variable susceptibility to hypersecretion and airflow obstruction in smokers or why reversible airways obstruction develops in many patients with chronic bronchitis. Retention of secretions may be a major factor in some instances. Immunologic factors and other mediators of bronchoconstriction may play a role, since some patients have subacute or chronic bronchospasm re-sembling classic asthma.
Pathology Enlargement of mucous glands in the large airways, the most characteristic abnormality, is primarily due to increased numbers of their constituent cells (hyperplasia) rather than to enlargement of cells (hypertrophy). Retained bronchial secretions and variable degrees of inflammatory changes in the bronchial wails are also identified. Narrowing or obliteration of some small airways, increased mucus in these airways, and scattered centrilobular emphysema may be found, even though clinically significant obstruction is absent. Since asymptomatic smokers may have similar small airways and emphysematous changes, it is unclear whether these alter-ations are related to simple chronic bronchitis, except through a common association with cigarette smoking.
Clinical Manifestations When the disease is mild, cough occurs when the patient arises or usually after he or she smokes the first cigarette of the day. The cough is productive of a small amount of mucoid sputum and occurs most regularly in the winter months. As the severity increases, the patient coughs throughout the day, symptoms are present throughout the year, sputum volume increases, and episodes of severe coughing develop. Near the end of a severe paroxysm of coughing, wheezing may occur, probably owing to cough-in-duced bronchospasm. Lying down may induce wheezing, which is probably caused by retained secretions, for cough often provides relief.
Sympotoms associated with purulent sputum, suggesting overgrowth of bacteria, may reappear after a viral respiratory infection. Hemophilus influezae and Streptococcus pneumoniae may be present, but sputum cultures usually show normal na-sopharyngeal flora.
Bacterial organisms probably represent secondary pathogens rather than being the primary cause of these exacer-bations of symptoms. During exacerbations, various degrees of bronchospasm may also develop, blurring the distinction be-tween such episodes and asthma. Whereas blood-streaked spu-tum is noted occasionally, severe or repeated hemoptysis may indicate a more serious entity, such as a pulmonary neoplasm.
The sputum may become chronically purulent as the dis-order progresses, and the term mucopurulent bronchitis may be applied at this stage of the disease. Rarely, drug-resistant organisms (e. g., Pseudomonas aeruginosa) are identified on sputum cultures, especially if the patient has received multiple antibiotics.
In mild disease, the physical examination may be normal. As the disease advances, variable coarse crackles, which may clear or change location with coughing, and scattered wheezes are heard. A forced expiratory maneuver often induces a wheeze or a paroxysm of coughing.
If reversible airways obstruction is present, the patient may resemble the typical asthmatic person, with wheezing and slowing of forced expiration as prominent features.
Laboratory Findings The chest radiograph, blood counts, and the differential smear are all normal in the uncom-plicated case. Leukocytes and a mixed flora of organisms are noted on sputum examination. Although spirometry often shows some slowing of forced expiration, flow rates may be normal in simple bronchitis. Individuals with chronic asthmat-ic bronchitis may have severe airways obstruction even between acute attacks. During episodes of bronchospasm in patients with asthmatic bronchitis, functional abnormalities are more severe, and both blood and sputum eosinophilia may her pre-sent.
Course and Prognosis In patients with simple chronic bronchitis, symptoms may fluctuate widely.Increased cigarette use, inclement weather, and acute respiratory infec-tions all tend to enhance cough and sputum production. Cessa-tion of smoking in mild cases usually leads to disappearance of symptoms. A slight reduction in ventilatory function is com-mon in simple chronic bronchitis, but progressive respiratory insufficiency does not necessarily develop.
The long-term outcome of patients with asthmatic bron-chitis has not been studied extensively. Some patients may be-come asymptomatic for years after an intial excellent response to therapy, while others require progressively more medication to control bronchospasm. Progress to irreversible airways ob-struction occurs in at least a few patients despite good medical management.
Differential Diagnosis A persistent, productive cough not attributable to an upper respiratory tract disorder, and al-lergic reactoin of the airways, a specific endobronchial disease, or parenchymal lung disease justifies the diagnosis of chronic bronchitis. Exclusion of a parenchymal lesion requires a chest radiograph. Moreover, a careful upper airway examination should be done, and physical findings, such as a persistent, lo-calized wheeze, must be sought to identify a localized airways disorder. Cystic fibrosis must be excluded in children and in young adults who have severe symptoms of chronic bronchitis. In addition, in individuals with one of the immotile cilia syn-dromes, symptoms of chronic bronchitis may be noted.
When there is no identifiable source of chronic bronchial irritation, the diagnosis of simple chronic bronchitis should be made with caution. Sputum and blood eosinophilia should be sought in a nonsmoking patient whose symptoms are associated with exposure to allergens or in a patient with episodes of com-bined wheezing and dyspnea. Asthmatic bronchitis, which may respond to bronchodilators or corticosteroids, is suggested by high eosinophil levels.
Bronchoscopy and even bronchography or a computed to-mography(CT) scan of the chest may be indicated to rule out an endobronchial lesion or localized bronchiectasis in patients with severe or repeated hemoptysis or with physical findings suggesting localized disease. In the routine case, these proce-dures are not indicated.
Severe mucopurulent bronchitis may be difficult to distin-guish from bronchiectasis. In fact, in persons with severe bronchitis, the bronchi may show mild, diffuse, cylindrical di-latation. Saccular bronchiectasis is suggested by 1.repeated pneumonias in the same lung zone, 2.honeycombed areas on the chest radiograph, and 3.recurrent hemoptysis. Bronchog-raphy provides an accurate diagnosis, but this invasive proce-dure is usually indicated only if resection of the bronchiectatic area or areas is considered. Otherwise there is little difference between the therapy for mucopurulent bronchitis and that for bronchiectasis. CT of the chest has been used successfully to diagnose localized and diffuse bronchiectasis.
Treatment Cigarette smoking should stop, and any oth-er bronchial irritants should be removed initially, since this step alone may relieve the symptoms. If the symptoms persist after the maximal effort to avoid provoking factors, the follow-ing measures are applied.
Antibiotic Therapy Infection is considered present when the patient is producing a noneosinophilic, purulent sputum. A 7 to 10 day course of tetracycline or ampicillin (
The antibiotic may have to be changed on the basis of drug susceptibility studies when resistant organisms are cul-tured from the sputum. (For severe, purulent exacerbations, penicillin has proved to be inadequate therapy. )
Bronchodilators The bronchodilator agents are the mainstays for managing bronchospasm associated with simple chronic bronchitis and for control of any reversible component of COPD. They are also useful in conjunction with bronchial hygiene therapy, described below. Both of the main classes of bronchodilators, the methylxanthines and the beta-adrenergic agonists, help to relieve bronchospasm and to prevent recur-rent attacks. The inhaled route of administering beta-adrener-gic drugs is usually more effective and rapid in relieving bron-chospasm than the oral route. Patients must be carefully in-structed, however, in the proper technique for utilizing in-halers. Inhaled atropine may exhibit a combined beneficial ef-fect of reducing copious amounts of sputum and partially reliev-ing bronchospasm in the person with severe bronchitis.
Corticosteroids When significant airways obstruction persists or recurs in the patient with asthmatic bronchitis in spite of maximal therapy with bronchodilators, corticosteroids are indicated. If the patient is ambulatory, modest dosages (e. g., 20 to 40 mg of prednisone per day) are administered for several days and then tapered to the lowest dose that will sus-tain improvement. Often, improvement is rapid, and the drug can be discontinued in 7 to 10 days. Thereafter, a short "burst" of corticosteroids is used to treat occasional relapses. In some patients, tapering corticosteroids leads to recurrence
Once bronchospasm has been relieved and a maintenance dose of corticosteroid achieved, an inhaled, poorly absorbed preparation such as beclomethasone should be added. This medication is inhaled from a pressurized container, two to four puffs (100 to
After the addition of an inhaled agent, the dose of oral prednisone should be reduced slowly (over several months) to avoid adrenal insufficiency in corticosteroid-dependent patient who has received months or years of systemic medication. In up to 30 per cent of patients, oropharyngeal candidiasis occurs because of inhaled corticosteroids. This condition responds, however, to specific therapy and rarely requires discontinua-tion of the inhaled preparation. Nasal symptoms, previously controlled by oral prednisone, may recur, requiring reinstitu-tion of oral agents.
Bronchial Hygiene These measures are designed to clear retained bronchial secretions. Deep breathing followed by de-liberate coughing is the most important maneuver. Sputum production may be more effective if the most involved lung re-gions are in the superior position (postural drainage) and chest percussion and vibration are applied.
Bronchial hygiene measures may be better tolerated and more effective if the patient is premedicated with an inhaled bronchodilator and then inhales a bland mist to loosen secre-tions. Although some patients are convinced of its efficacy, objective benefits of bland mist therapy have been difficult to establish. Because patients' reactions to this therapy vary, only measures that prove effective should be continued, since the full program is uncomfortable and time consuming.
To avoid inspissation of secretions, patients should be en-couraged to keep well hydrated. Intravenous fluids may be re-quired for acute exacerbations. Although the efficacy of expec-torant medications has not been established, some authorities recommend 10 to 12 drops of a saturated solution of potassium iodide three times daily. This program is associated with a high rate of side effects, some severe; yet it does seem benefi-cial in some patients. Cough syrups and lozenges have little ef-fect on the viscosity of bronchial secretions, but they may re-lieve a "tickle" in the throat of many persons with bronchitis. Cough sedatives should be used only for acute episodes of a se-vere, nonproductive cough and are otherwise contraindicated.