Tuberculosis (TB) is a bacterial disease that mainly affects the lungs. It is caused by the bacteria Mycobacteria tuberculosis and is spread through airborne droplets from an infected person.
Before the discovery of certain antibiotic drugs in the 1940s, TB was the leading cause of death in the United States. Even though TB is not as common as it once was in the U.S., there has been a resurgence in recent years due to HIV, AIDS, and the spread of drug-resistant forms of TB. It is still a major health problem throughout the world, especially in poor countries.
If you have been exposed to TB, you may be infected but have no symptoms and not be contagious. Between 20 to 30% of people exposed to a person with active TB become infected. For that reason, doctors usually distinguish between infection (or a positive TB test) and an active infection. After you are infected, your immune system will attack the bacteria. Your body may kill all the bacteria, the bacteria may remain in your body but not cause an active infection, or you may develop the disease. TB can affect other areas of your body outside of the lungs, but lung infection is most common. Typically, TB bacteria that grow in the lungs may cause:
- Mild fever
- Night sweats
- Loss of appetite, weight loss
- Cough, with or without mucus and pus
- Coughing up blood
- Chest pain from inflammation in the lungs
- Difficulty breathing
- Swollen glands
- Sore throat
Who Is Most at Risk?
Because TB is only spread through inhalation of infected respiratory particles in the air, you are not likely to contract the infection through other means, such as handshakes or sharing dishes and utensils. People with TB are most likely to spread it to people with whom they spend the most time, such as family members, friends, classmates, and coworkers. Risk factors for developing TB include:
- Working in the health care profession or as an embalmer
- Being born in, or spending time in, a country where TB is common (for instance, most countries in Latin America and the Caribbean, Africa, and Asia, excluding Japan)
- Living in overcrowded, unsanitary settings where TB is common (for example, homeless shelters, migrant farm camps, prisons and jails, and some nursing homes or long-term care facilities)
- Having HIV or AIDS. As HIV attacks the immune system, existing TB infections may become active, or it may make it easier for someone to catch TB. The TB bacteria, in turn, cause the HIV virus to replicate more quickly.
- Using medications that suppress the immune system (Remicade, Enbrel)
- Organ transplantation
- Having no or inadequate access to health care
- Having diabetes (the risk of contracting TB is 2 to 3 times higher among people who have diabetes compared to people who do not have diabetes)
- Having a rheumatic disease
If your doctor suspects a TB infection, you will need a skin test. A positive reaction to the test means you are likely infected with TB, although false positive and false negative results are possible. To confirm the diagnosis and determine if the infection is active, you may need to have samples taken of your sputum (mucus and other material coughed up from the lungs) or stomach fluid to check for TB bacteria, as well as a chest x-ray.
Tuberculosis Prevention and Treatment
TB is difficult to treat so prevention is important. Prevention of TB begins with rapid diagnosis and treatment to avoid spread to noninfected persons. In countries where TB is common, a vaccine called BCG may be administered. However, the vaccine causes a false positive on the skin test and is not very effective in adults, so it is rarely given in the U.S.
If you are at risk, you should be tested for TB every 6 months. If you test positive but have no signs of active infection, you may be given the medication isoniazid to prevent an active infection.
The most important way to keep TB from spreading is for infected people to take their medications exactly as prescribed. If you do not take all of your medications, you run the risk of developing multidrug resistant TB, which you can then spread to others. Drug resistant TB is a major health problem in the U.S. and around the world. If you have TB, keeping all of your clinic appointments is essential so that your doctor can check for side effects from the drugs and evaluate the effectiveness of the treatment. If you are sick enough with TB to go to a hospital, you may be put in a special room with air vents that keep the TB bacteria from spreading. You will most likely be prevented from leaving your room while you are contagious (about 2 weeks after treatment begins). People who come into the room will wear special face masks to protect themselves from TB bacteria and to prevent the spread of TB bacteria to others.
If your doctor suspects TB, treatment may begin before all lab tests return. This may include more than one anti-TB drug. Emergency treatment may be necessary if, for example, you are coughing up blood.
TB bacteria die very slowly. It takes 6 months to a year for the medicine to destroy all of the TB bacteria, longer for multidrug resistant TB. If you have TB, you will need to take several different drugs. You will be tested first for drug resistance to determine the most effective combination of drugs to prevent the bacteria from becoming resistant to the drugs. The most common drugs used to fight TB are:
- Isoniazid (INH)
U.S. public health policy requires health care providers to report cases of TB and to treat or quarantine all people infected. Most people may remain at home, but all should be kept from any new contacts for at least 2 weeks after treatment begins. The elderly and those who are acutely ill or have multidrug resistant TB should be hospitalized for the first few weeks of treatment.
It is essential to take all TB medication exactly as prescribed in order to cure TB and prevent drug resistance. Doctors will collect and test sputum samples monthly. If tests are still positive after 3 months of treatment, the infection is considered multidrug resistant and a change in medications is in order.
- Infants born to mothers with infectious TB should be separated from the mother until she is no longer contagious. The infant should then be tested for TB at 4 to 6 weeks and 3 to 4 months.
- Women can be treated for TB during pregnancy and while breastfeeding but should avoid streptomycin and pyrazinamide.
Since effective treatment of TB depends on taking multiple antibiotic drugs for an extended period of time, it is essential that you consult with your health care provider before using complementary or alternative therapies, including taking herbs and vitamin supplements.