Reviewed by Dr. Michael Iseman

Tuberculosis (TB) may be regarded in two categories: active disease or latent infection. The most common form of active TB is lung disease, but it may invade other organs, so-called "extrapulmonary TB."


Active TB Disease

Active TB is an illness in which the TB bacteria are rapidly multiplying and invading different organs of the body. The typical symptoms of active TB variably include cough, phlegm, chest pain, weakness, weight loss, fever, chills and sweating at night. A person with active pulmonary TB disease may spread TB to others by airborne transmission of infectious particles coughed into the air.

If you are diagnosed with an active TB disease, be prepared to give a careful, detailed history of every person with whom you have had contact. Since the active form may be contagious, these people will need to be tested, as well.

Multi-drug treatment is employed to treat active TB disease. Depending on state or local public health regulations, you may be asked to take your antibiotics under the supervision of your physician or other healthcare professional. This program is called "Directly Observed Therapy" and is designed to prevent abandonment or erratic treatment, which may result in "failure" with continued risk of transmission or acquired resistance of the bacteria to the medications, including the infamous multi-drug resistant TB (MDR-TB).


Miliary TB

Miliary TB is a rare form of active disease that occurs when TB bacteria find their way into the bloodstream. In this form, the bacteria quickly spread all over the body in tiny nodules and affect multiple organs at once. This form of TB can be rapidly fatal.


Latent TB Infection

Many of those who are infected with TB do not develop overt disease. They have no symptoms and their chest x-ray may be normal. The only manifestation of this encounter may be reaction to the tuberculin skin test (TST) or interferon-gamma release assay (IGRA). However, there is an ongoing risk that the latent infection may escalate to active disease. The risk is increased by other illnesses such as HIV or medications which compromise the immune system. To protect against this, the United States employs a strategy of preventive therapy or treatment of latent TB infection.

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