Pulmonary tuberculosis (TB) is a slowly developing bacterial lung infection characterized by progressive necrosis of lung tissue. An inflammatory response begins with phagocytosis. Growths of inflamed, granular-appearing tissue (granulomas) form and, when they calcify, leave lesions that may be visible on an x-ray. The lymph and blood generally are affected.
Pulmonary TB is a common cause of death in the world. The arrival of nearly 400,000 immigrants and over 50,000 refugees per year from overseas contributes to the rise of TB in the United States. The incidence of TB also is increasing due to homelessness, substance abuse, and HIV infection – all related to individuals who are less likely to receive adequate medical attention. In general, TB is more common among elderly persons, the urban poor, and members of minority groups.
Pulmonary TB is caused by Mycobacterium tuberculosis. The infected individual’s immune system usually is able to wall the bacteria into a tubercle or tiny nodule. The bacteria can lie dormant for years and then reactivate and spread when conditions are favorable. The disease is transmitted in aerosol droplets exhaled by infected individuals. Note: Although the lungs are the organs most commonly infected, the bacteria can infect other parts of the body as well.
Signs and Symptoms
Pulmonary TB may be asymptomatic. The onset generally is insidious. When symptoms are present, they are often vague and may include cough, lassitude, malaise, fatigability, night sweats, anorexia, afternoon fever, weight loss, pleuritic chest pain, hemoptysis, and wheezing.
FIGURE. Anteroposterior x-ray of a patient diagnosed with advanced bilateral pulmonary tuberculosis. (Centers for Disease Control and Prevention, 1972.)
A thorough physical examination, chest x-ray or CT scan, bronchoscopy, and positive tuberculin test often confirm the diagnosis. The tuberculin test of choice is the Mantoux test, which consists of an intradermal injection of a purified protein derivative (PPD) of the tuberculin bacillus. The TB skin test cannot determine if the disease is active. This determination requires sputum analysis (smear and culture) in the laboratory. The sensitive PCR (polymerase chain reaction) test can detect the genetic material of the bacteria, usually within a few days. The bacteria may be identified in the sputum, urine, body fluids, or tissues of the client. Pulmonary and pleural biopsies may be ordered.
Drug therapy is indicated in every case of pulmonary TB. There are many TB drugs, however, and these can be used in a number of different ways. To prevent the development of resistance, TB drugs are administered in combinations of two or more (usually four) in most instances. Prolonged use of about 6 months is essential. Bed rest and isolation are indicated until the person is strong enough to resume activities.
A whole-foods and nutritious diet combined with vitamin supplements can be helpful. Enhancing the body’s immune response with fresh air, rest, light exercise, and relaxation will prove beneficial.
Teach clients to cough and sneeze into tissues and to properly dispose of all secretions. Remind them of the importance of taking all their medications. Teach family members about the infectious nature of the disease and proper medication regimen. Individuals exposed to someone with pulmonary TB disease should contact their primary care provider or local health department about getting a TB skin test.
The prognosis for an individual with active pulmonary TB is good if the disease is detected early and if the client follows the prescribed regimen of drug therapy. However, if strains of bacteria are resistant to two or more of the major antituberculosis agents, mortality rates increase.
Preventive measures include proper infection control, tuberculin testing of persons known to have been in close contact with infected persons, and treatment of individuals reacting to the tuberculin testing. Generally, a person with a positive tuberculin reaction is put on 1 year of isoniazid prophylactically. Use of the bacille Calmette-Guerin (bCG) vaccination should be considered only for very select persons who meet specific criteria and in consultation with a TB expert.