Updated: November 21, 2017
Tuberculosis or TB is a contagious infection that usually attacks the lungs which is caused by a type of bacteria called Mycobacterium tuberculosis(MTB).
The bacteria that cause tuberculosis are spread from one person to another through tiny droplets released into the air through coughs and sneezes. It can also spread to other parts of the body, like the brain and spine.
A physical examination will be done by your doctor to check your lymph nodes for swelling and will use a stethoscope to listen carefully to the sounds your lungs make while you breathe. They will also ask about symptoms and medical history as well as assess your risk of exposure to TB. Different type of test done to diagnose TB include:
The most common diagnostic test for TB is a skin test where a small injection of PPD tuberculin, an extract of the TB bacterium, is given just below the inside forearm.
Within 48 to 72 hours, a health care professional will check your arm for swelling at the injection site. A hard, raised red bump signifies that you are likely to have TB infection. The size of the bump determines whether the test results are significant.
A false-positive test may happen if you have been vaccinated recently with the bacillus Calmette-Guerin (BCG) vaccine. This may also happen with people who sometimes do not respond to the TB skin test, for example children, older people and people with AIDS. A false-negative result can also occur in people who have recently been infected with latent TB.
Blood tests may be used to confirm or rule out latent or active tuberculosis by measuring your immune system's reaction to TB bacteria. Examples of TB blood tests are QuantiFERON-TB Gold in-Tube test and T-Spot. A blood test may be useful if you are at high risk of TB infection but have a negative response to the skin test, or if you have recently received the BCG vaccine.
A chest X-ray or a CT scan can be done which will show white spots in your lungs where your immune system has walled off TB bacteria, or it may reveal changes in your lungs caused by active tuberculosis. CT scans provide more detailed images than X-rays.
If your chest X-ray shows signs of tuberculosis, your doctor may take samples of your sputum to test for TB bacteria. Sputum samples can also be used to test for drug-resistant strains of TB which will helps your doctor choose the medications that are most likely to work. These tests can take 4 to 8 weeks to be completed.
TB can be cured with the right diagnosis and medication . The precise type and length of antibiotic treatment depends on a person's age, overall health, potential resistance to drugs, whether the TB is latent or active, and the location of infection such as the lungs, brain or kidneys. People with latent TB may need just one kind of TB antibiotics, whereas people with active TB particularly if it is a drug-resistant strain will often require a prescription of multiple drugs.
Antibiotics are usually required to be taken for a relatively long time. The standard length of time for a course of TB antibiotics is about 6 to 9 months. The most common medications used to treat tuberculosis are Rifampin, Isoniazid, Pyrazinamide and Ethambutol.
If you have drug-resistant TB, a combination of antibiotics called fluoroquinolones and injectable medications, such as kanamycin, amikacin or capreomycin are generally used for 20 to 30 months. Some types of TB are resistance to these medications as well.
Although side effects of medicines are uncommon, when they do occur, they can be quite serious. All tuberculosis medications can be highly toxic to your liver. Potential side effects should be reported to a doctor which include:
It is crucial that you should finish the full course of therapy and take the medications exactly as prescribed by your doctor even if the TB symptoms have gone away. After a few weeks, you won't be contagious and you may start to feel better. Any bacteria that have survived the treatment could become resistant to the medication that has been prescribed and could lead to developing MDR-TB in the future which is is much more dangerous and difficult to treat.
Directly observed therapy (DOT) may be recommended which involves a healthcare worker administering the TB medication to ensure that the course of treatment is completed.