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What System Is Tuberculosis From?

Tuberculosis is an ancient and lethal enemy of the human race; the earliest evidence of TB in humans goes back more than 3000 years. Today, one-third of the world's population is infected, according to the Centers for Disease Control, and nearly two million people die of TB every year. Tuberculosis generally infects the lungs or respiratory system but can sometimes attack other parts of the body as well.

  1. The TB Bacterium

    • The bacterium that causes tuberculosis is called Mycobacterium tuberculosis or MTB. Inside the lungs, it's engulfed by a macrophage, a kind of white blood cell that eats invaders; the macrophage, however, is unable to digest MTB as it would other bacteria, and the TB germ can actually continue to replicate inside the macrophage. Most infections with MTB are latent, meaning that there are no symptoms and the person with the infection cannot spread the disease. Typically the body successfully "walls off" the bacteria in one of the alveoli of the lungs. The bacteria may then lie dormant, often for many years; sometimes it will later reactivate to develop into an active infection. A mere 10 percent of people with a latent infection with MTB will ever go on to develop an active infection. Only people with active infections can transmit the disease.

    Respiratory System

    • MTB typically infects the alveoli of the lungs, which are part of the respiratory system. From there, however, it can sometimes migrate to other regions of the body, including the lymph nodes (part of the lymphatic system) and the meninges or membranes of the central nervous system. This is an especially common problem in immunocompromised patients like people with HIV. TB lung infections are also called pulmonary tuberculosis; infections that have spread beyond the lungs to other parts of the body are called extrapulmonary tuberculosis.

    Lymph System

    • The most frequently observed form of extrapulmonary TB is lymphadenitis or inflammation of the lymph nodes. The most common site of infection is in the neck, where TB infection of lymph nodes causes characteristic swelling.

    Central Nervous System

    • MTB can occasionally infect the meninges or membranes that envelop the nervous system, causing meningitis (inflammation of the meninges). This condition can rapidly become extremely dangerous. Symptoms may include headache, fever, vomiting, confusion and personality changes. In patients with tubercular meningitis, physicians will often continue antibiotic treatment for even longer than usual.

    Gastrointestinal System

    • Swallowing infected sputum can sometimes spread the infection to the gastrointestinal system(the digestive tract); the bacteria can also infiltrate the gastrointestinal system from adjacent organs. Common symptoms are rectal bleeding, abdominal pain, diarrhea and fever.

    Genitourinary System

    • Tuberculosis can sometimes infect the genitourinary tract and infect the kidneys or the reproductive system. In some cases the prostate gland, the testes, the ovaries or the endometrium of the uterus can become infected.

    Musculoskeletal System

    • Extrapulmonary TB can spread to bones and joints, causing joint swelling, pain, and decreased range of motion. The spine is a common site of infection in these cases.

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