Pulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs. It may spread to other organs.
TB; Tuberculosis - pulmonary
Pulmonary tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis (M. tuberculosis). You can get TB by breathing in air droplets from a cough or sneeze of an infected person. The resulting lung infection is called primary TB.
Most people recover from primary TB infection without further evidence of the disease. The infection may stay inactive (dormant) for years. In some people, it becomes active again (reactivates).
Most people who develop symptoms of a TB infection first became infected in the past. In some cases, the disease becomes active within weeks after the primary infection.
The following persons are at high risk of active TB:
- People with weakened immune systems, for example due to AIDS, chemotherapy, diabetes, or medicines that weaken the immune system
Your risk of catching TB increases if you:
- Are around people who have TB (such as during overseas travel)
- Live in crowded or unclean living conditions
- Have poor nutrition
The following factors can 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
The primary stage of TB does not cause symptoms. When symptoms of pulmonary TB occur, they can include:
- Breathing difficulty
- Chest pain
- Cough (usually with mucus)
- Coughing up blood
- Excessive sweating, especially at night
- Weight loss
Exams and Tests
The doctor or nurse will perform a physical exam. This may show:
- Clubbing of the fingers or toes (in people with advanced disease)
- Swollen or tender lymph nodes in the neck or other areas
- Fluid around a lung (pleural effusion)
- Unusual breath sounds (crackles)
Tests that may be ordered include:
The goal of treatment is to cure the infection with medicines that fight the TB bacteria. Treatment of active pulmonary TB will always involve a combination of many medicines (usually four medicines). All medicines are continued until lab tests show which medicines work best.
You may need to take many different pills at different times of the day for 6 months or longer. It is very important that you take the pills the way your health care provider instructed.
When people do not take their TB medicines as instructed, the infection can become much more difficult to treat. The TB bacteria can become resistant to treatment. This means the medicines no longer work.
When there is a concern that a patient may not take all the medicines as directed, a health care provider may need to watch the person take the prescribed medicines. This approach is called directly observed therapy. In this case, medicines may be given 2 or 3 times a week, as prescribed by a doctor.
You may need to stay at home or be admitted to a hospital for 2 to 4 weeks 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 ensure that you receive the best care.
You can ease the stress of illness by joining a support group. Sharing with others who have common experiences and problems can help you feel more in control.
Symptoms often improve in 2 to 3 weeks after starting treatment. A chest x-ray will not show this improvement until weeks or months later. Outlook is excellent if pulmonary TB is diagnosed early and effective treatment is started quickly.
Pulmonary TB can cause permanent lung damage if not treated early.
Medicines used to treat TB may cause side effects, including:
- Changes in vision
- Orange- or brown-colored tears and urine
- Liver inflammation
A vision test may be done before treatment so your doctor can monitor any changes in the health of your eyes.
When to Contact a Medical Professional
Call your health care provider if:
- You think or know you have been exposed to TB
- You develop symptoms of TB
- Your symptoms continue despite treatment
- New symptoms develop
TB is preventable, even in those who have been exposed to an infected person. Skin testing for TB is used in high risk populations or in people who may have been exposed to TB, such as health care workers.
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.
A positive skin test means you have come into contact with the TB bacteria. It does not mean that you have active disease or are contagious. Talk to your doctor about how to prevent getting tuberculosis.
Prompt treatment is extremely important in preventing the spread of TB from those who have active TB disease to those who have never been infected with TB.
Some countries with a high incidence of TB give people a BCG vaccination to prevent TB. But, the effectiveness of this vaccine is limited and it is not routinely used in the United States.
People who have had BCG may still be skin tested for TB. Discuss the test results (if positive) with your doctor.
Ellner JJ. Tuberculosis. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 332.
Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Mandell GL, Bennett JE, Dolan R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 250.
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.