Tuberculosis

What is Tuberculosis?
Tuberculosis (TB) is an infectious disease (usually involving the lungs) caused by a bacteria called Mycobacterium tuberculosis. It is spread through the air from person to person and generally requires prolonged or intense exposure to someone with active TB disease.

What are the symptoms of Tuberculosis?
Symptoms may vary from person to person, and generally include:

  • Weakness or fatigue
  • Loss of appetite
  • Weight loss
  • Fever and/or night sweats

Specific symptoms of TB disease in the lungs may include:

  • Prolonged cough
  • Chest pain
  • Coughing up blood

How is Tuberculosis spread?
TB is spread only from a person with active TB disease. The TB bacteria are released into the air in tiny droplets from the nose, mouth, or lung fluid of a person with active lung disease when he or she coughs, sneezes, laughs, sings, or speaks. Coughing spreads the most bacteria. These tiny droplets of bacteria must be inhaled to infect people. Those who are most often infected are people who share close spaces, usually over a prolonged period of time. TB is not spread by brief contact in large open areas or by handling objects previously handled by an infected person.

What is latent Tuberculosis?
In most people who are exposed to the TB bacteria and become infected, the body is able to fight off and inactivate the bacteria, even though the bacteria remain alive in the body and can become active later. This is called a latent TB infection. People with latent TB have no symptoms:

  • They do not feel ill
  • They cannot spread TB to others
  • They usually have a positive TB skin test (called a Mantoux test)
  • They can develop TB later in life if they do not receive prophylactic TB treatment

Many people who have latent TB never develop the disease — the disease remains inactive for a lifetime — but in others, especially those who may have a weakened immune system, the bacteria may become active and cause infectious TB.

What is active Tuberculosis?
TB bacteria become active if the immune system cannot prevent them from growing. As the active bacteria increase in the body, TB disease occurs. Some people develop TB soon after being exposed, before their immune system can fight off the TB bacteria. Others may become ill later when for some reason their immune system is weakened. Babies and young children, especially under the age of four, have immature immune systems and may be more susceptible to infection. Other people who may be more at risk of developing active TB include those with:

  • HIV or AIDs
  • Substance abuse
  • Silicosis
  • Diabetes
  • Cancer of the head or neck
  • Leukemia or Hodgkin’s disease
  • Severe kidney disease
  • Low body weight
  • Certain medical treatments such as corticosteroids, chemotherapy, or medications needed to prevent rejection after organ transplantation

How is Tuberculosis diagnosed?
A Mantoux skin test is performed. For those who may have been exposed to TB, a skin test is done at the time of known exposure and then repeated in 8 to 10 weeks. The second test in 8 to 10 weeks is very important because that is the length of time it usually takes for the skin test to become positive and indicate that the TB bacteria is present in the body. This only means the person has been infected, it does not mean they have active disease. Other tests, including a chest X-ray, are required for further evaluation. In most cases, prophylactic medications are prescribed to prevent the bacteria present from becoming active, both for now and for the future.