Tuberculosis (TB) is an infectious disease caused by the bacteria mycobacterium tuberculosis, that usually attacks the lungs, but can attack almost any part of the body. Tuberculosis is spread from person to person through the air. TB is a serious world-wide problem, especially in Africa where the spread is facilitated by HIV/AIDS (which weakens immunity if untreated) and other factors like poverty, poor nutrition, inadequate healthcare, etc. Estimates suggest that TB kills some 1.5 million people worldwide each year.
When people with TB in their lungs or throat cough, the bacteria that cause TB may be spread into the air (so-called “droplet spread”). If another person breathes in these bacteria there is a chance that they will become infected with tuberculosis.
TB is usually spread between family members, close friends, and people who work or live together. TB is spread most easily in closed spaces over a long period of time whereas casual once-off contact does not usually lead to spread.
There is a difference between being infected with TB and having TB disease.
- Someone who is infected with TB has the TB bacteria in their body. The body’s defences are still protecting them and they are not sick or infectious to others. It is thought that some 25% of the world’s population have this form of latent TB, with the figure likely to be higher is certain areas like Africa.
- Someone with TB disease is sick (the bacteria has overwhelmed the body’s defences) and can spread the disease to other people.
When someone becomes infected with tuberculosis that does not mean they will get TB disease. Only about 10 per cent of these people will develop TB disease in their lifetime. The other 90 percent will never get sick from the TB germs or be able to spread them to other people.
High-risk groups include:
- HIV positive people
- People with suppressed immunity (diabetics, people on chemotherapy)
- People living in areas with high incidence of TB (e.g. Africa)
- Residents of long-term care facilities (nursing homes, prisons, some hospitals)
- People who are malnourished
- Alcoholics
- Drug users
Symptoms include:
- Cough
- Fatigue
- Weight loss
- Loss of appetite
- Fever
- Coughing up blood
- Night sweats
- Chest pain
- Symptoms from other systems (brain, kidneys, liver, etc.) if the TB has spread
Tests used to confirm the diagnosis include:
- Chest X-Ray usually shows typical changes, but the appearances can be confused with other lung conditions.
- Skin testing (mantoux test, tuberculin test) may help to show whether a person has antibodies to TB.
- Sputum (mucous) from the chest is tested to confirm the presence of mycobacterium tuberculosis.
Treatment for TB depends on whether a person has TB disease or only TB infection.
- TB infection: A person who has become infected with TB, but does not have TB disease, may be given preventive therapy. Preventive therapy aims to kill germs that are not doing any damage right now, but could break out later. Isoniazid (INH) is usually given in this setting.
- TB disease: The patient usually gets a combination of several drugs (most frequently INH plus two to three others such as rifampicin, pyrazinamide, and ethambutol), usually for six to nine months. The patient will probably begin to feel better only a few weeks after starting to take the drugs.
Hospitalisation is only needed when the person is very ill. Most people can return to work within a few weeks, and will not be a risk to work colleagues at this stage – most patients stop being infectious within 2-3 weeks of starting proper treatment.
In areas where TB remains common, BCG vaccination is given routinely, to all children. This does help to reduce the risk of contracting TB (20% reduced risk) and of becoming ill with TB (60% reduced risk) and so it remains important today.
Resistance: If the medicine is taken incorrectly (or stopped prematurely) and the patient becomes sick with TB a second time, the TB may be harder to treat this time around, because it has become drug resistant. This means that the TB germs in the body are unaffected by some drugs used to treat TB. Multi-drug resistant TB is very dangerous, so patients should be sure that they take all of their medicine correctly and complete the course.
TB generally responds well to treatment but resistance is a growing problem around the world. In addition, those who are HIV positive do not do well if they are not on HIV treatment and their immunity is very low.
Tuberculosis (TB) is an infectious disease caused by bacteria that primarily attack the lung. Anyone can get TB but those with suppressed immunity (HIV/AIDS, diabetes, chemotherapy) are most at risk. 90 percent of infected people do not get ill because their body’s defences cope. Symptoms may include cough, weight loss, fever, night sweats, and chest pain. Diagnosis is usually confirmed by Chest X-Ray appearance and sputum (mucous) testing for the presence of the bacteria. Treatment uses multiple antibiotics over a long period (from 3-9 months) and is usually effective but compliance is important to prevent resistance (where bacteria do not respond to treatment) and complications.
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