Tuberculosis, also called TB, is a contagious disease that usually affects the lungs, but can spread to other parts of the body. Like the common cold, it spreads through the air, but only people who are sick with TB in their lungs are infectious.

How common is TB?
TB is not a new disease. It has been around for centuries, but since the 1990s the incidence of new cases has increased dramatically. Globally there are about 8.8 million people with TB with the largest number of cases in South-east Asia and sub-Sahara Africa. It is estimated that 1.6 million deaths result from TB in 2005.

What causes TB?
TB is caused by the bacilli mycobacterium tuberculosis; a slow growing organism that thrives in areas of the body that are rich in blood and oxygen e.g. the lungs. When infectious people who harbour the TB bacilli cough, sneeze, talk or spit, they propel the TB germs into the air. A person needs only to inhale a small number of these bacilli to be infected. A person can be infected with the bacilli but does not actually have TB disease. Only a few persons (about 5-10%) who are infected with the TB organism go on to develop the disease. People who do have the disease are said to have “active” TB. Healthy people who get infected with TB bacilli are able to fight off the infection and do not get TB disease. The bacteria are dormant (inactive) in their lungs (inactive or dormant TB). If the body in not able to fight off the infection and the bacteria continues to grow, active TB develops.

How can your doctor check for TB?
The most commonly used method to check for TB is the tuberculin skin test (PPD). If you have a positive PPD, it means you have been exposed to a person who has active TB. A positive tuberculin test does not necessarily mean you have TB disease. If your tuberculin test is positive your doctor will arrange for you to have a complete physical examination: including a chest X-ray and a sputum sample taken to identify the TB bacilli. Your doctor might arrange for other investigations to make the diagnosis of TB disease.

What are the symptoms of TB?
If you have inactive TB (dormant or latent TB), you will not have any symptoms unless the disease becomes active. The symptoms of active TB include the following:
• Not feeling well
• Persistent cough that produces thick or bloody sputum
• Feeling tired
• Weight loss
• Difficulty breathing
• Fever or sweating at nights (called night sweats). This is different to hot flashes in menopausal or peri-menopausal women.

What is the treatment for active TB?

If you have active TB, your doctor will often recommend four medications and these should be taken for at least six months.Individual must not skip a single dose. Direct observational treatment ensures that individuals follow medication instructions which often results in improve cure rates. The individuals will need regular checkups and various investigations for the rest of their lives to ensure that they stay free of disease. Almost every individual who has TB disease and takes his/her medications as prescribed can be cured from the disease. Latent cases of TB should also be treated with medications.

Have you been exposed to TB organism?

If you think you have been exposed to an individual who has active TB you should contact your health care provider as soon as possible and do not wait until you have symptoms.

Conclusion

Tuberculosis (TB) is a contagious disease caused by a slow growing bacillus. Only individuals who have active TB are infectious and spread the infected organisms through the air. It is estimated that one-third of the world’s population is currently infected with TB bacilli, but only 5-10% of them become sick and develop active TB at some time during their life. Active TB can be successfully treated with use of a combination of medications, but left untreated the TB bacilli can spread to other organs like the kidneys, bones spine and the brain and can possible result in death. If you think you have been exposed to an individual with active TB please see your health care provider for testing for TB as soon as possible.

Ask Your Doctor is a health education column and is not a substitute for medical advice from your physician. Dr. Brett Hodge is an obstetrician/gynecologist and family doctor who has over 20 years in clinical practice.

Dr. Hodge has a medical practice in the Johnson Building in The Valley.

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