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Tuberculosis

Tuberculosis - Conditions & Treatments | SingHealth

Tuberculosis - What is it for

Tuberculosis - Conditions & Treatments SingHealth

Tuberculosis, or TB for short, is a disease caused by bacteria called Mycobacterium tuberculosis. Tuberculosis is a serious disease that can cause a person to become very sick if not treated appropriately. 

Tuberculosis is caused by infection from the microbe, Mycobacterium tuberculosis. Although the most common site of infection is the lung, tuberculosis may also cause infections in other parts of the body, such as bone, joints, lymph nodes, gastrointestinal tract, kidneys, intestines, covering of the heart known as the pericardium, brain, and liver. 

Not all persons develop tuberculosis when exposed to the Mycobacterium tuberculosis. Once exposed, some people may not develop tuberculosis, others may develop latent infection (where there are no signs and symptoms) whilst others may develop active infection or disease (either early after exposure or many years later when the latent tuberculosis reactivates).

How is tuberculosis spread?

Tuberculosis is spread through the air from one person to another. The bacteria is passed through the air droplets when someone who is sick with has tuberculosis in the lung coughs, laughs, sings, or sneezes. When you breathe air that has the tuberculosis bacteria, you may get an infection without a disease process (latent TB). This means you have dormant bacteria in your body that does not make you sick and cannot be passed to anyone else. If these dormant bacteria wake up and multiply, you will get sick with TB disease (active TB).

If you have tuberculosis infection, the chances of getting an active infection disease increases if you have HIV infection or other health problems such as diabetes that make it difficult for your body to fight bacteria. 

You cannot get tuberculosis bacteria from sharing drinking containers or eating utensils, sharing cigarettes, or saliva shared from kissing.

Can tuberculosis affect other parts of the body?

Tuberculosis usually affects the lungs, but it can also affect other parts of the body such as lymph nodes, bones and joints, kidneys, intestines, covering of the heart known as the pericardium, brain and liver.

Tuberculosis - Symptoms

Patients with tuberculosis disease may complain of persistent cough, sometimes this may be productive of blood-stained sputum, fever and chills, night sweats, loss of appetite, loss of weight, and easy fatigability.

As mentioned earlier, people who develop latent infection are asymptomatic When active infection develops, it typically runs a sub-acute to chronic course. You may experience non-specific constitutional symptoms such as fatigue, unexplained weight loss and loss of appetite, night sweats and intermittent fevers. More specific symptoms would depend on the site of the actual disease. For example, in tuberculosis infection of the lung, you may experience prolonged cough and sputum production; and in lymph node disease, you may experience swelling of the lymph nodes.

Tuberculosis - How to prevent?

Childhood BCG (Bacillus Calmette-Guerin) vaccination is part of childhood vaccination in Singapore. BCG vaccination when administered during childhood is effective for the prevention of disseminated tuberculosis and tuberculosis meningitis in children. BCG vaccination only provides partial protection. You can still develop tuberculosis even if you have previously received the BCG vaccination in childhood.

For public health considerations, only those with active tuberculosis in the lungs/airways can spread it in the community through their respiratory secretions. When a person with active tuberculosis in the lungs/airways coughs, the microbe, Mycobacterium tuberculosis, can be aerosolized and therefore be passed to other individuals around them. It is therefore very important for patients who have tuberculosis in the lungs/airways to be identified, diagnosed and treated early to prevent the spread of this infection in the community.

Tuberculosis - Causes and Risk Factors

Tuberculosis - Diagnosis

A screening chest radiograph can be done. Though a normal radiograph does not exclude tuberculosis, there is a much lower likelihood of having tuberculosis disease (active TB) of the lung if the radiograph is normal. Latent tuberculosis is diagnosed by a skin test or a blood test. It is a measure of immunity against Mycobacterium tuberculosis. 

Active tuberculosis, on the other hand, is diagnosed by sending body fluid/ tissue samples (e.g. blood, sputum, or body tissue) to the laboratory to be incubated. The diagnosis of active tuberculosis is confirmed when the incubated samples are found to be positive for growth of Mycobacterium tuberculosis. This process may take up to 2 months as it is a slow growing organism. Nowadays, modern technology such as DNA testing has allowed for easier and more rapid diagnosis. Nonetheless, the diagnosis of active tuberculosis infection can remain difficult and all the available testing methods may still yield a negative result. In such cases, the diagnosis and management depends very much on the clinical acumen and judgement of the physician.

Tuberculosis - Treatments

Tuberculosis disease (active TB) can be treated very effectively with a combination of appropriate drugs. Treatment may take up to 6 months or more, but as long as they are taken as prescribed, the disease usually can be cured. Latent tuberculosis treatment is usually with a single drug, and administered for a few months, the duration is dependent on the medication selected. Active tuberculosis, however, needs to be treated with a combination of anti-tuberculosis medications. Treatment duration is prolonged and may run from 6 months or longer depending on the severity, site of the infection as well as the selection of medications used for the treatment of tuberculosis. Lung infection is usually treated for 6 months. During treatment, the physician will be closely monitoring the patient for any medication related side effects such as drug allergy, liver inflammation, kidney impairment or suppression of blood counts. As treatment course is prolonged, patients need to be reminded to be compliant to daily medications to prevent the development of treatment failure or drug resistant tuberculosis. When you are on tuberculosis medications, you need to inform your doctors of other medications that you are taking due to the possibility of drug interactions.

More reading

American Lung Association: http://www.lungusa.org/
CDC: http://www.cdc.gov/tb

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  • Updated on 2018-05-20T16:00:00Z

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