Tuberculosis, commonly known as TB, is a bacterial infection which affects the lungs. It is a serious condition which can spread to the bones and nervous system, causing symptoms including weight loss, a severe and persistent cough and sweats during the night.
This is a condition that used to be very common and remains a major global health threat. However, since antibiotics and vaccinations were introduced in the UK, the number of cases of the disease has decreased significantly. In less developed countries, tuberculosis is a common problem and contributed to 1.7 million deaths in 2009. In the last 20 years, there has been a steady increase in the number of cases of tuberculosis in the UK. This is largely due to the increase in immigration, as cases are more common among ethnic minorities originating from countries where the infection is still widespread. In the UK, the incidence of tuberculosis was 21 times higher among people who were not born in the UK than those who were born in the country in 2009.
What causes tuberculosis?
Tuberculosis is caused by a strain of bacteria known as the mycobacterium tuberculosis. The infection is spread by droplets of infected saliva, which are released when you sneeze or cough. Although tuberculosis is contagious, it is not as infectious as the common cold and you have to spend a long time with an infected person to catch the infection. It is highly unlikely that you would develop the infection from sitting next to somebody who has it. Anyone can be infected but there are certain factors that increase your risk:
- Continual close contact with somebody who has the infection (for example, if you are living with an infected person).
- Visiting or travelling to a country where tuberculosis is common.
- Having a weakened immune system (this can be caused by conditions such as HIV, taking medication such as steroids or receiving treatment such as chemotherapy).
- Age: very young and old people have a higher risk, as their immune systems are weaker.
- Living in poor housing conditions and being in poor health.
- Ethnicity: people from ethnic minorities originating from countries where tuberculosis is common have a higher risk of being infected.
Symptoms of tuberculosis
Symptoms of tuberculosis do not become apparent until the infection has spread to the lungs, which is known as pulmonary tuberculosis. Symptoms include:
- Weight loss.
- Loss of appetite.
- A persistent cough.
- Coughing up phlegm and, in some cases, blood.
- Fever (a high temperature).
- Generally feeling unwell.
- Breathlessness, which tends to get progressively worse.
In some cases, TB can spread to other parts of the body, including the lymph nodes, bones, joints and the nervous system. This is known as extrapulmonary tuberculosis and symptoms include:
- Swollen lymph nodes (painless).
- Discharge of fluid from the lymph nodes.
- Bone and joint pain.
- Lack of movement in the joints.
- Weakened bone tissue.
- A stiff neck.
- Passing blood in the urine.
- Blurred vision.
It is important to see your GP if you experience a cough for more than three weeks, you cough up blood or if you have symptoms that get worse or do not go away.
How is tuberculosis diagnosed?
If you have symptoms associated with tuberculosis your doctor will ask you questions about the symptoms, medical history and order relevant tests. The tests used will depend on the type of tuberculosis your doctor suspects. For pulmonary TB a chest X-ray is usually sufficient to make a diagnosis, but samples of phlegm and mucus will also be analysed to check for the presence of the bacteria that causes tuberculosis. If your doctor suspects that you may have extrapulmonary tuberculosis, they will refer you to a specialist and order a number of tests, including:
- A CT scan.
- MRI scan.
- Blood sample.
- Ultrasound scan.
- Urine test.
In some cases, patients may be screened for latent tuberculosis, which occurs when a patient is infected but does not have any symptoms. Screening may be carried out if you have been in close contact with someone who has the infection, or if you have recently moved to the UK from a country where tuberculosis is common.
Treatment for tuberculosis
Treatment for tuberculosis usually lasts for around six months. If you are diagnosed with pulmonary tuberculosis, you will be cared for by a team comprised of specialist doctors (including a pulmonologist) and nurses, your GP, and a health visitor and key worker will also be assigned. Pulmonary TB is treated with two main types of antibiotics, known as rifampicin and isoniazid, every day for six months, and two medications, known as ethambutol and pyrazinamide every day for the first two months of the treatment course. In most cases, people are no longer infectious after two weeks, but it is essential to complete the course of antibiotics. Treatment for extrapulmonary tuberculosis is similar to treatment for pulmonary tuberculosis. However, you may need to take antibiotics for twelve months rather than six. If your heart or lungs have been affected, you may be prescribed corticosteroids.
Treatment is usually recommended for people with latent tuberculosis if they are aged under 35, they work in the healthcare industry or they have HIV.
If you are diagnosed with tuberculosis it is important that you try to prevent the infection from spreading. You should cover your mouth when you cough or sneeze, throw away used tissues, open windows at home and stay away from individuals while you are infectious.
There is a vaccination that can help protect against tuberculosis, known as BCG (Bacillus Calmette-Guerin). The vaccination is recommended for people who live in high risk areas and have a parent or grandparent who were born in a country where Bacillus Calmette-Gueri is common. Vaccinations are also advised for people who work in the healthcare industry, veterinary practice or prison force. Immunisation may also be recommended if an individual has been exposed to an infected person but hasn’t developed the infection. However, the vaccination is not usually given to people with latent TB because it does not provide any benefits and can cause side-effects.