Chapter 153 Bronchitis and Pneumonia
Bronchitis is inflammation of the mucous membranes of the bronchi, the airways that carry airflow from the trachea into the lungs. Pneumonia is inflammation of the lungs. Both acute bronchitis and pneumonia are characterized by the development of a cough with or without the production of sputum. Acute bronchitis often occurs during the course of an acute viral illness such as the common cold or influenza. Viruses cause about 90% of cases of acute bronchitis.
Although pneumonia may appear in healthy individuals, it is usually seen in those who are immune-compromised, particularly drug and alcohol abusers. The growing population of those with chronic lung diseases and other debilitating illnesses and a history of the use of respiratory therapy, immunosuppressive drugs, and other such technologies have contributed to the further increase of nosocomial and opportunistic pneumonias, which have high mortality rates. Acute pneumonia is the seventh leading cause of death in the United States.1 It is particularly dangerous in the elderly.
In healthy individuals, pneumonia most often follows an insult to the host defense mechanisms: viral infection (especially influenza), cigarette smoke and other noxious fumes, impairment of consciousness (which depresses the gag reflex, allowing aspiration), neoplasms, and hospitalization (Table 153-1). In immunocompetent, nonelderly adults, cigarette smoking is the strongest independent risk factor for invasive pneumococcal disease.2
|Viral (influenza)||20 (3)|
|Bacterial superimposed on viral||6|
|Unknown cause (Legionnaires’ disease, toxic)||38|
Data from Branch WT Jr. Office practice of medicine. Philadelphia: Saunders, 1982:57-76.
The airway distal to the larynx is normally sterile owing to several protective mechanisms, both mechanical and humoral. The mucus-covered ciliated epithelium that lines the lower respiratory tract propels sputum to the larger bronchi and trachea, evoking the cough reflex. The respiratory secretions contain substances that exert nonspecific antimicrobial actions: alpha1 antitrypsin, lysozyme, and lactoferrin. At the level of the alveoli, potent defense mechanisms are present, including alveolar macrophages, a rich vasculature capable of rapidly delivering lymphocytes and granulocytes, and an efficient lymphatic drainage network.
The diagnosis of acute bronchitis is usually made by ruling out other causes of an acute cough—such as pneumonia, the common cold, acute asthma, or an exacerbation of chronic obstructive pulmonary disease.
In patients with the presumed diagnosis of acute bronchitis, viral cultures, serologic assays, and sputum analyses should not be routinely performed because the responsible organism is rarely identified in clinical practice.
In patients with acute cough and sputum production suggestive of acute bronchitis, the absence of the following findings reduces the likelihood of pneumonia sufficiently to eliminate the need for a chest radiograph: (1) heart rate greater than 100 beats per minute; (2) respiratory rate greater than 24 breaths per minute; (3) oral body temperature above 38° C; and (4) chest examination findings of focal consolidation, egophony, or fremitus.
Examination of the sputum suggestive of infection includes the presence of blood; thick, opaque sputum colored yellow, green, or brown and a positive Gram stain. Sputum culture and sensitivity are not always helpful in identifying the cause of pneumonia due to contamination of the sample with throat or mouth bacteria.
A urine test (Binax NOW, Binax Inc., Scarborough, Maine) can detect Streptococcus pneumonia or Legionella pneumophila antigens within 15 minutes. It may identify up to 77% of pneumonia cases and may rule out the infection in 98% of patients who do not have S. pneumoniae. However, the test is not very useful in diagnosing S. pneumoniae as a cause of pneumonia in children, since the organism is so common in this population whether or not they have pneumonia. L. pneumophila is the bacterium that causes Legionnaires’ disease and sometimes pneumonia.
A chest x-ray is nearly always taken to confirm a diagnosis of pneumonia, but it is not imperative that it be positive to make the clinical diagnosis. A positive chest x-ray for pneumonia may reveal lung infiltrates or complications of pneumonia such as pleural effusions.
Viral pneumonia is most often caused by one of several viruses: adenovirus, influenza, parainfluenza, and respiratory syncytial virus. Viral pneumonia is responsible for about 30% of cases of pneumonia and will often develop as a complication to an upper respiratory infection caused by one of the viruses. People who are at risk for more serious viral pneumonia often are immunocomprimised. Antibiotics are of no value in viral pneumonia.
Mycoplasmal pneumonia is caused by Mycoplasma pneumoniae.Mycoplasma is a genus of bacteria that lack cell walls. Various studies suggest that M. pneumoniae is responsible for 15% to 50% of all cases of pneumonia in adults and even more than those in school-age children. It is often referred to as “walking pneumonia.” Antibiotics are usually not necessary but may speed recovery. Effective classes of antibiotics that may be effective against M. pneumoniae include macrolides, quinolones, and tetracyclines.
Pneumococcal pneumonia (due to Streptococcus pneumoniae) is the most common bacterial pneumonia and the most common cause of pneumonia requiring hospitalization. Careful clinical judgment is necessary in determining the severity of the disease and the status of the patient’s immune system because it is often necessary to administer antibiotics or to refer for hospitalization, especially for elderly or immunocompromised patients.
Unfortunately, most reports show an increase not only of resistance rates to antibiotic therapy but also of the proportion of highly resistant strains.3–5 In two multinational studies, the worldwide prevalence of penicillin- and macrolide-resistant S. pneumoniae ranged from 18% to 22% and from 24% to 31%, respectively.6,7 Given this information, it is important to consider natural treatments in cases resistant to antibiotics or as an adjunctive treatment to strengthen the immune response and increase the therapeutic effect.
Regardless of the form of bronchitis or pneumonia, the basic approach is to use an expectorant, mucolytic, and immune supportive nutrients to help resolve it. Although antibiotics are of limited value in acute bronchitis, they definitely have their place in treating pneumonia.
Botanical expectorants have a long history of use in bronchitis and pneumonia. Because impaired cough reflexes have been thought to play a role in recurrent bronchitis and pneumonia,8 it seems reasonable that these botanicals would be useful in helping relieve this condition and preventing recurrences. Botanical expectorants act to increase the quantity, decrease the viscosity, and promote expulsion of the secretions of the respiratory mucous membranes. Many also have antibacterial and antiviral activity. Some expectorants are also antitussives; however, Lobelia inflata, a commonly used expectorant, actually helps promote the cough reflex.9 Therefore Lobelia may be more effective at clearing the lungs than other expectorants when the cough is productive. Other commonly used expectorants include Glycyrrhiza glabra (licorice), Pelargonium sidoides (South African geranium), Hedera helix (ivy), and wild cherry bark.