Pulmonary tuberculosis (TB) is a contagious bacterial infection that mainly involves the lungs, but may spread to other organs.
TB; Tuberculosis - pulmonary
Pulmonary tuberculosis is caused by the bacteria Mycobacterium tuberculosis (M. tuberculosis). You can get tuberculosis by breathing in air droplets from a cough or sneeze of an infected person.
In the United States, most people will recover from primary TB infection without further evidence of the disease. The infection may stayasleep or nonactive (dormant) for years and then reactivate.
Most people who develop symptoms of a TB infection first became infected in the past. However, in some cases, the disease may become active within weeks after the primary infection.
The following people are at higher risk for active TB:
- People with weakened immune systems, for example due to AIDS, chemotherapy, or antirejection medicines given after an organ transplant
Your risk of contracting TB increases if you:
- Are in frequent contact with people who have the disease
- Have poor nutrition
- Live in crowded or unsanitary living conditions
The following factors may increase the rate of TB infection in a population:
- Increase in HIV infections
- Increase in number of homeless people (poor environment and nutrition)
- The appearance of drug-resistant strains of TB
In the United States, there are approximately 10 cases of TB per 100,000 people. However, rates vary dramatically by area of residence and socioeconomic class.
- Cough (sometimes producing phlegm)
- Coughing up blood
- Excessive sweating, especially at night
- Unintentional weight loss
Other symptoms that may occur with this disease:
- Breathing difficulty
- Chest pain
Signs and tests
Examination may show:
- Clubbing of the fingers or toes (in people with advanced disease)
- Enlarged or tender lymph nodes in the neck or other areas
- Fluid around a lung
- Unusual breath sounds (crackles)
Tests may include:
- Biopsy of the affected tissue (rare)
- Chest CT scan
- Chest x-ray
- Interferon-gamma blood test such as the QFT-Gold test to test for TB infection
- Sputum examination and cultures
- Tuberculin skin test
The goal of treatment is to cure the infection with drugs that fight the TB bacteria. Treatment of active pulmonary TB will always involve a combination of many drugs (usually four drugs). It is continued until lab tests show which medicines work best.
You may need to take many different pills at different times of the day. This may be difficult for some people. However, it is very important that you take the pills the way your health care provider instructed.
When people do not take their tuberculosis medications as recommended, the infection becomes much more difficult to treat. Sometimes, the drugs no longer help treat the infection.
Treatment usually lasts for 6 months, but longer courses may be needed for people with AIDS or who get better slowly.
You may need to be admitted to a hospital to avoid spreading the disease to others until you are no longer contagious.
Your doctor or nurse is required by law to report your TB illness to the local health department. Your health care team will be sure that you receive the best care for your TB.
You can ease the stress of illness by joining a support group where members share common experiences and problems.
Symptoms may improve in 2 - 3 weeks. A chest x-ray will not show this improvement until later. The outlook is excellent if pulmonary TB is diagnosed early and treatment is begun quickly.
Pulmonary TB can cause permanent lung damage if not treated early.
Medicines used to treat TB may cause side effects, including liver problems. Other side effects include:
- Changes in vision
- Orange- or brown-colored tears and urine
Calling your health care provider
Call your health care provider if:
- You have been exposed to TB
- You develop symptoms of TB
- Your symptoms continue despite treatment
- New symptoms develop
TB is a preventable disease, even in those who have been exposed to an infected person. Skin testing (PPD) for TB is used in high risk populations or in people who may have been exposed to TB, such as health care workers.
A positive skin test indicates TB exposure and an inactive infection. Discuss preventive therapy with your doctor. People who have been exposed to TB should be skin tested immediately and have a follow-up test at a later date, if the first test is negative.
Prompt treatment is extremely important in controlling the spread of TB from those who have active TB disease to those who have never been infected with TB.
People who have had BCG may still be skin tested for TB. Discuss the test results (if positive) with your doctor.
See also: Tuberculosis - pulmonary
Miliary tuberculosis; Tuberculosis - disseminated; Extrapulmonary tuberculosis
Causes, incidence, and risk factors
Tuberculosis infection can develop after inhaling droplets sprayed into the air from a cough or sneeze by someone infected with the Mycobacterium tuberculosis bacteria. Small areas of infection, called granulomas (granular tumors), develop in the lungs.
The usual site of tuberculosis is the lungs, but other organs can be involved. In the U.S., most people with primary tuberculous get better and have no further evidence of disease. Disseminated disease develops in the small number of infected people whose immune systems do not successfully contain the primary infection.
Disseminated disease can occur within weeks after the primary infection, or may lie dormant for years before causing illness. Infants, the elderly, and those infected with HIV are at higher risk for the disease worsening, because of their weaker immune systems.
In disseminated disease, organs and tissues affected can include:
- Bones and joints
- Cervical lymph nodes
- Larynx (voice box)
- Lining of the abdominal cavity (peritoneum)
- Lining of the brain and spinal cord (meninges)
- Lining of the heart (pericardium)
- Organs of the male or female urinary and reproductive systems
- Small bowel
The risk of catching TB increases when you are in contact with people who have the disease, if you live in crowded or unsanitary conditions, and if you have poor nutrition.
Another matter of concern is the development of drug-resistant strains of TB. Incomplete treatment of TB infections (such as not takingmedications for the prescribed length of time) can contribute to the development of drug-resistant strains of bacteria.
The primary infection usually has no symptoms.
Symptoms of disseminated tuberculosis include:
- General discomfort, uneasiness, or ill feeling (malaise)
- Shortness of breath
- Weight loss
Other symptoms that can occur with this disease:
- Abdominal swelling
- Joint pain
- Pale skin due to anemia (pallor)
- Swollen glands
Signs and tests
A physical exam may show:
- enlarged liver
- enlarged lymph nodes
- enlarged spleen.
Tests for tuberculosis include:
- Biopsies and cultures of affected organs or tissues
- Bronchoscopy for biopsy or culture
- Chest x-ray
- Fundoscopy may reveal retinal lesions
- Open lung biopsy
- Pleural biopsy
- Sputum cultures
- Tuberculin skin test
This disease may also alter the results of the following tests:
- Mycobacterial culture of bone marrow
- Peripheral smear
- Serum calcium (may be elevated)
The goal of treatment is to cure the infection with antitubercular drugs. These drugs include:
- Isoniazid (INH)
- Para-aminosalicylic acid (PAS)
Daily oral doses are continued for 1 year or longer. Directly observed therapy, in which a health care provider watches the patient take the prescribed antitubercular drugs, is the most effective strategy for some patients. In this case, drugs may be given 2 or 3 times per week, as prescribed by a doctor.
For atypical tuberculosis infections, or drug-resistant strains, other drugs may be used to treat the infection. Treatment starts with a minimum of three drugs.
Hospitalization may be necessary to prevent spreading the disease to others until the infectious period is over, usually 2-4 weeks after the start of therapy. People can continue their normal activities after the infectious period.
Most disseminated forms of TB respond well to treatment.
All medications used to treat TB can have side effects. Rifampin, pyrazinamide, and isoniazid may cause liver inflammation. Rifampin may also turn the tears and urine an orange or brown color, and can stain contact lenses and undergarments. Ethambutol may reduce vision or cause color blindness.
Other complications include:
- Adult respiratory distress syndrome (ARDS)
- Drug resistance
- Relapse of the disease
- Respiratory failure
· Calling your health care provider
· Call your health care provider if you know or suspect that you have been exposed to TB. All forms of TB need prompt evaluation and treatment.
· The vaccine BCG is sometimes given to people who don't have tuberculosis, but who have been or may be exposed to people with untreated TB. Its effectiveness is unclear. It is rarely used in the United States but is often used abroad, in countries with higher rates of tuberculosis.
risk for Infection [spread/reactivation]: risk factors may include inadequate primary defenses (decreased ciliary action/stasis of secretions, tissue destruction/extension of infection), lowered resistance/suppressed inflammatory response, malnutrition, environmental exposure, insufficient knowledge to avoid exposure to pathogens, or inadequate therapeutic intervention.*
ineffective Airway Clearance may be related to thick, viscous, or bloody secretions; fatigue/poor cough effort, and tracheal/pharyngeal edema, possibly evidenced by abnormal respiratory rate, rhythm, and depth; adventitious breath sounds (rhonchi, wheezes), stridor, and dyspnea.
risk for impaired Gas Exchange: risk factors may include decrease in effective lung surface, atelectasis, destruction of alveolar-capillary membrane, bronchial edema; thick, viscous secretions.*
Activity Intolerance may be related to imbalance between O2 supply and demand, possibly evidenced by reports of fatigue, weakness, and exertional dyspnea.
imbalanced Nutrition: less than body requirements may be related to inability to ingest adequate nutrients (anorexia, effects of drug therapy, fatigue, insufficient financial resources), possibly evidenced by weight loss, reported lack of interest in food/altered taste sensation, and poor muscle tone.
risk for ineffective Therapeutic Regimen Management: risk factors may include complexity of therapeutic regimen, economic difficulties, family patterns of health care, perceived seriousness/benefits (especially during remission), side effects of therapy.*