Tuberculosis (TB)

Tuberculosis is a serious disease that causes each year a significant number of deaths throughout the world. Although the infection rate in Canada is low, vigilance is still required.

One rarely becomes ill when exposed to the tuberculosis-causing bacteria. In most affected individuals, the bacteria remain dormant and cause no symptoms. This is known as latent infection.

When the immune system is weak, the bacteria can multiply and cause the active disease, with associated symptoms and affecting one or several organs. Being malnourished, undergoing cancer treatments or being HIV positive (the virus that causes AIDS) are but a few examples of factors that can weaken the immune system's defences. The bacteria can attack the lungs (the most common form of tuberculosis) as well as the bones, the kidneys, the brain, etc.

Causes

Tuberculosis is contagious and transmitted by droplets in the air usually coming from the cough or the sneezes of an infected person. The infected person must have active TB symptoms and the disease must also be active in the lungs. If all these factors are present, persons who are sick can transmit the tuberculosis bacteria to those with whom they have close or frequent contact, over an extended period of time, such as loved ones.

Symptoms

TB symptoms will vary depending on the organs affected by the disease. The most common symptoms, however, include:

• fatigue
• fever and chills
• agitation and night sweats
• loss of appetite and weight loss

Pulmonary tuberculosis, which affects the lungs, may also be accompanied by symptoms such as:

• increased respiration rate
• abnormal sputum colour or sputum laced with blood
• coughing

Other symptoms can appear depending on the location of the tuberculosis infection.

Diagnosis

In Canada, tuberculosis is a reportable disease which means that each case has to be reported to the government. The objective of this measure is to make prevention and nationwide reaction easier in the event of an epidemic.

Several tests can be used to diagnose tuberculosis. The disease can be identified with a tuberculin skin test (TST) even when individuals do not present any symptoms. The skin reaction is verified after the injection of a small amount of tuberculin. Tuberculin is a protein derived from tuberculosis bacteria. It can be requested that an X-ray of the lungs or a sample of sputum for lab analysis be made, to determine whether the disease is in an active phase.

Treatment

The treatment for tuberculosis generally involves taking a combination of antibiotics for several months. If the disease is diagnosed in a latent phase (when there are no symptoms), treatment may be shorter. It is extremely important to follow your health care professional's orders by the book and to see the treatment through to the end. Even though symptoms have diminished or disappeared, there may still be bacteria present and they could build resistance to the medications. This would make them more difficult to eliminate afterwards. The disease is no longer contagious after several weeks of treatment.

For more information:

• Canadian Lung Association