Tuberculosis (TB) is caused by a type of bacterium called mycobacterium tuberculosis.

TB is spread when a person with an active TB infection in their lungs coughs or sneezes and someone else inhales the expelled droplets containing TB bacteria.

However, although it is spread in a similar way to cold or flu, TB is not as contagious. You would usually have to spend prolonged periods in close contact with an infected person to catch the infection yourself.

For example, TB infections usually spread between family members who live in the same house. It would be highly unlikely to become infected by sitting next to an infected person on a bus or train.

Not everyone with TB is infectious. Generally, children with TB or people with TB that occurs outside the lungs (extrapulmonary TB) do not spread the infection.

Latent or active TB

Your immune system will usually be able to defeat the bacteria that cause TB. However, in some cases the bacteria infect the body but don’t cause any symptoms (latent TB) or the infection will begin to cause symptoms within weeks or months (active TB).

About 10% of people with latent TB develop active TB years after the initial infection. This usually happens when the immune system is weakened, for example during chemotherapy.

Increased risk

Anyone can catch TB, but people particularly at risk include:

• those living in environments where the level of existing TB infection is higher than normal
• people with health conditions such as HIV or whose circumstances mean they are less able to fight off a TB infection

Other things that can increase your risk of developing an active TB infection include:

• being in close contact with someone who is infected
• having lived in, travelled to or had visitors from parts of the world where TB is common
• being part of an ethnic group that originated in parts of the world where TB is still common
• having a weakened immune system because of HIV, diabetes or other medical conditions
• having a weakened immune system because of long courses of medication, such as corticosteroids, chemotherapy or tumour necrosis factor blockers (used to treat some types of arthritis) 
• being very young or very old – the immune systems of people who are young or elderly tend to be weaker than those of healthy adults
• being in poor health or having a poor diet due to lifestyle and other problems, such as drug misuse, alcohol misuse or homelessness
• living in poor or crowded housing conditions, such as prisons

Several tests are used to diagnose tuberculosis (TB), depending on the type of TB suspected.

Your GP may refer you to a TB specialist for testing and treatment if they think you have TB. 

Pulmonary TB

A diagnosis of pulmonary TB (TB that affects the lungs) can be difficult.

Several tests are usually needed, including a chest X-ray. This uses radiation to create an image of your lungs. If you have a TB infection, changes to the appearance of your lungs, such as scarring, should be visible on the X-ray.

Other tests may also be necessary to confirm a diagnosis. For example, samples of mucus and phlegm will also be taken and checked under a microscope for the presence of TB bacteria.

These tests are important in helping decide what will be the most effective treatment.

Extrapulmonary TB

If you have suspected extrapulmonary TB (TB that occurs outside the lungs), several tests can be used to confirm a diagnosis. These include:

• a computerised tomography (CT) scan – a series of X-rays of your body is taken at slightly different angles and a computer puts the images together to create a detailed picture of the inside of your body
• a magnetic resonance imaging (MRI) scan – a strong magnetic field and radio waves are used to produce detailed images of the inside of your body
• an ultrasound scan – high-frequency sound waves create an image of part of the inside of your body
• blood tests 
• urine tests
• a biopsy – a small tissue sample is taken from the affected site and tested for the presence of disease

You may also have a lumbar puncture. This involves taking a small sample of cerebrospinal fluid from the base of your spine. Cerebrospinal fluid is a clear fluid that surrounds the brain. The cerebrospinal fluid will be checked to see whether TB has infected your central nervous system.

Screening for latent TB

In some circumstances, you may need to be screened to check for a latent TB infection. This is when you have been infected with the TB bacteria but do not have any symptoms.

For example, you may need to be screened if you have been in close contact with someone known to have an active TB infection (an infection that causes symptoms), or if you have recently spent time in a country where TB levels are high.

If you have just moved to the UK from a country where TB is common, you may be screened when you arrive or your GP may suggest screening when you register as a patient.

If you need to be screened for TB, you may be referred to Public Health England (PHE) or a local TB clinic. PHE helps protect public health by providing support and advice to organisations such as the NHS.

PHE or your local TB clinic will be your point of contact if you are involved in an outbreak of TB or need to be screened. See the PHE website or your local hospital website for more information about how they are involved in cases of TB.

Mantoux test

The Mantoux test is a widely used test for latent TB. It involves injecting a substance called PPD tuberculin into the skin of your forearm.

If you have a latent TB infection, your skin will be sensitive to PPD tuberculin and a hard red bump will develop at the site of the injection, usually within 48 to 72 hours of having the test. If you have a very strong skin reaction, you may need a chest X-ray to confirm whether you have an active TB infection. 

If you do not have a latent infection, your skin will not react to the Mantoux test. However, as TB can take a long time to develop, you may need to be screened again within a year.

If you have had the Bacillus Calmette-Guérin (BCG) vaccination, you may have a mild skin reaction to the Mantoux test. This does not mean you have latent TB, but that your immune system (the body’s natural defence against infection and illness) recognises TB.

Interferon gamma release assay (IGRA)

The interferon gamma release assay (IGRA) is a newer type of blood test for TB that is becoming more widely available. 

The IGRA may be used to help diagnose latent TB:

• if you have a positive Mantoux test 
• as part of your TB screening if you have just moved to the UK from a country where TB is common
• as part of a health check when you register with a GP
• if you are about to have treatment that will suppress your immune system
• if you are a healthcare worker 

Tuberculosis (TB) is a bacterial infection spread through inhaling tiny droplets from the coughs or sneezes of an infected person.

It is a serious condition but can be cured with proper treatment.

TB mainly affects the lungs. However, it can affect any part of the body, including the bones and nervous system.

Typical symptoms of TB include:

• having a persistent cough for more than three weeks that brings up phlegm, which may be bloody
• weight loss 
• night sweats 
• high temperature (fever)
• tiredness and fatigue
• loss of appetite

You should see a GP if you have a cough that lasts more than three weeks or if you cough up blood.

Read more about the symptoms of tuberculosis.

What causes tuberculosis?

TB is caused by a bacterium called mycobacterium tuberculosis.

TB that affects the lungs is the only form of the condition that is contagious and usually only spreads after prolonged exposure to someone with the illness. For example, TB often spreads within a family who live in the same house.

In most healthy people, the immune system (the body’s natural defence against infection and illness) kills the bacteria and you have no further symptoms.

However, sometimes the immune system cannot kill the bacteria, but manages to prevent it from spreading in the body. This means you will not have any symptoms, but the bacteria will remain in your body. This is known as latent TB. 

If the immune system fails to kill or contain the infection, it can spread to the lungs or other parts of the body and symptoms will develop within a few weeks or months. This is known as active TB.

Latent TB could develop into an active TB infection at a later date, particularly if your immune system becomes weakened.

Read more about the causes of tuberculosis.

How is tuberculosis treated?

With treatment, a TB infection can usually be cured. Most people will need a course of antibiotics, usually for six months.

Several different antibiotics are used. This is because some forms of TB are resistant to certain antibiotics. If you are infected with a drug-resistant form of TB, treatment can last as long as 18 months.

If you are in close contact with someone who has TB, tests may be carried out to see if you are also infected. These can include a chest X-ray, blood tests and a skin test called the Mantoux test.

Read more about diagnosing tuberculosis and treating tuberculosis.

Vaccination

The Bacillus Calmette-Guérin (BCG) vaccine can provide effective protection against TB in up to eight out of 10 people who are given it.

Currently, BCG vaccinations are only recommended for groups of people who are at a higher risk of developing TB.

This includes children living in areas with high rates of TB or those who have close family members from countries with high TB rates.

It is also recommended that some people, such as healthcare workers, are vaccinated due to the increased risk of contracting TB while working.

Read more about tuberculosis vaccine.

How common is TB?

Before antibiotics were introduced, TB was a major health problem in the UK. Nowadays, the condition is much less common. However, in the last 20 years TB cases have gradually increased, particularly among ethnic minority communities who are originally from places where TB is more common.

In 2011, 8,963 cases of TB were reported in the UK. Of these, more than 6,000 of these cases affected people who were born outside the UK.

It is estimated that one-third of the world’s population is infected with latent TB. Of these, about 10% will become active at some point.

The Map of Medicine is used by doctors throughout the NHS to determine the best treatment options for their patients. NHS Choices offers everyone in England exclusive and free access to this cutting-edge internet resource, which lets you see exactly what your doctor sees.

The information in the Map has been approved by the UK’s leading clinical experts, is based on the best available clinical evidence, and is continually updated. To take advantage of this unique resource go to:

Map of Medicine: tuberculosis

Map of Medicine: pleural effusion

The symptoms of tuberculosis (TB) depend on where the infection occurs.

TB usually develops slowly. Your symptoms might not begin until months or even years after you were initially exposed to the bacteria.

In some cases the bacteria infect the body but don’t cause any symptoms, which is known as latent TB. It is called active TB if the bacteria cause symptoms.

Read more about the causes of tuberculosis.

Pulmonary tuberculosis (TB)

A TB infection of the lungs is known as pulmonary TB. In the UK, just over half of TB infections are pulmonary TB.

Symptoms include:

• a persistent cough of more than three weeks that brings up phlegm, which may be bloody 
• breathlessness, which is usually mild to begin with and gradually gets worse
• lack of appetite and weight loss
• a high temperature of 38ºC (100.4ºF) or above
• night sweats 
• extreme tiredness or fatigue
• unexplained pain for more than three weeks

When to get medical help

You should see your GP if you have a cough that lasts for more than three weeks or if you cough up blood.

Read more about coughing up blood.

Extrapulmonary tuberculosis (TB)

In some cases, TB can occur outside the lungs, which is known as extrapulmonary TB.

Extrapulmonary TB is more common in people with a weakened immune system, particularly people with an HIV infection. You are also more likely to develop extrapulmonary TB if you have previously been infected with TB but haven’t had any symptoms (a latent TB infection).

A TB infection can affect the:

• lymph nodes (lymph node TB)
• bones and joints (skeletal TB)
• the digestive system (gastrointestinal TB)
• the bladder and reproductive system (genitourinary TB)
• the nervous system (central nervous system TB)

These types of extrapulmonary TB can cause additional symptoms, which are described below.

Lymph node TB

Lymph nodes are small glands that are part of the immune system. They remove unwanted bacteria and particles from the body. Symptoms of lymph node TB include:

• persistent, painless swelling of the lymph nodes, which usually affects nodes in the neck, but swelling can occur in nodes throughout your body 
• over time, the swollen nodes can release fluid through the skin

Skeletal TB

Symptoms of skeletal TB include:

• bone pain
• curving of the affected bone or joint
• loss of movement or feeling in the affected bone or joint
• weakened bone that may fracture easily

Gastrointestinal TB

Symptoms of gastrointestinal TB include:

• abdominal pain
• diarrhoea 
• rectal bleeding 

Genitourinary TB 

Symptoms of genitourinary TB include:

• a burning sensation when you urinate
• blood in your urine 
• a frequent urge to pass urine during the night
• groin pain

Central nervous system TB

Your central nervous system consists of your brain and spinal cord. Symptoms of central nervous system TB include:

• headaches
• being sick 
• stiff neck
• changes in your mental state, such as confusion
• blurred vision
• fits (seizures)

Treatment for tuberculosis (TB) depends on which type you have, although a long course of antibiotics is most often used.

While TB is a serious condition that can be fatal if left untreated, deaths are rare if treatment is completed.

For most people, hospital admission during treatment is not necessary.

Pulmonary TB

If you are diagnosed with active pulmonary TB (TB that affects your lungs and causes symptoms), you will be referred to a specialist TB treatment team. This is a team of healthcare professionals with experience in treating TB.

Treatment team

Your TB treatment team may include: 

• a respiratory physician – a doctor who specialises in conditions that affect the lungs and breathing
• an infectious disease specialist 
• a TB nurse 
• a health visitor – a qualified nurse with extra training who helps families with babies and young children to stay healthy
• your GP
• a paediatrician (if necessary) – a doctor who specialises in conditions that affect children 

It is also likely that you will be assigned a key worker. This is usually a nurse, health visitor or social care support worker who will be the point of contact between you and the rest of the team and will help co-ordinate your care.

Antibiotics

Pulmonary TB is treated using a six-month course of a combination of antibiotics. The usual course of treatment is:

• two antibiotics – isoniazid and rifampicin – every day for six months 
• two additional antibiotics – pyrazinamide and ethambutol – every day for the first two months

However, you may only need to take these antibiotics three times a week if you need supervision.

It may be several weeks or months before you start to feel better. The exact length of time will depend on your overall health and the severity of your TB.

After taking the medicine for two weeks, most people are no longer infectious and feel much better. However, it is important to continue taking your medicine exactly as prescribed and to complete the whole course of antibiotics.

Taking medication for six months is the most effective method of ensuring that the TB bacteria are killed. If you stop taking your antibiotics before you complete the course or if you skip a dose, the TB infection may become resistant to the antibiotics. This is potentially serious, as it can be difficult to treat and will require a longer course of treatment.

If treatment is completed correctly, you should not need any further checks by a TB specialist afterwards. However, you may be given advice about spotting signs that the illness has returned, although this is rare.

In rare cases, TB can be fatal even with treatment. Death can occur if the lungs become too damaged to work properly.

Extrapulmonary TB

Extrapulmonary TB (TB that occurs outside the lungs) can be treated using the same combination of antibiotics as those used to treat pulmonary TB. However, you may need to take them for 12 months.

If you have TB that affects your brain, you may also be prescribed a corticosteroid, such as prednisolone, for several weeks to take at the same time as your antibiotics. This will help reduce any swelling in the affected areas.

As with pulmonary TB, it is important to take your medicines exactly as prescribed and to finish the course.

Latent TB

Latent TB is where you have been infected with the TB bacteria but do not have any symptoms of active disease. Treatment for latent TB is usually recommended for:

• people 35 years of age or under 
• people with HIV, regardless of their age
• healthcare workers, regardless of their age 
• people with evidence of scarring caused by TB, as shown on a chest X-ray, but who were never treated 

Treatment is not recommended for people who have latent tuberculosis and are over 35 years of age (and do not have HIV and are not healthcare workers). This is because the risk of liver damage increases with age and the risks of treatment outweigh the benefits for some people.

Latent TB is also not always treated if it is suspected to be drug resistant. If this is the case, you may be regularly monitored to check the infection does not become active.

In some cases, treatment for latent TB may be recommended for people requiring immunosuppressant medication. This medication suppresses the immune system (the body’s natural defence against illness and infection) and can allow latent TB to develop into an active form of the disease. This may include people taking long-term corticosteroids or people receiving chemotherapy.

In these cases, the TB infection should be treated before immunosuppressant medication begins.

Treatment for latent TB involves either taking a combination of rifampicin and isoniazid for three months, or isoniazid on its own for six months.

Side effects of treatment

Rifampicin can reduce the effectiveness of some types of contraception, such as the combined contraceptive pill. Use an alternative method of contraception, such as condoms, while taking rifampicin.

In rare cases, these antibiotics can cause damage to the liver or the eyes, which can be serious. Therefore, your liver function may be tested before you begin treatment. If you are going to be treated with ethambutol, your vision should also be tested at the beginning of the course of treatment.

Contact your TB treatment team immediately if you have any of the following symptoms:

• feeling sick or being sick 
• yellowing of your skin (jaundice) and darkening of your urine
• unexplained fever – a temperature of 38ºC (100.4ºF) or above
• tingling or numbness in your hands or feet
• skin rash or itchy skin
• changes to your vision, such as blurred vision or colour blindness

See medicines information for tuberculosis for more information about the side effects of your medication.

Supervised treatment

Sometimes people find it difficult to take their medication every day. If this affects you, your treatment team can work with you to find a solution. Usually, you will be asked to join a programme of “directly observed therapy”.

This can include supervised treatment, which will involve regular contact with your treatment team (daily or three times a week) to support you taking your medication. This can take place in your home, the treatment clinic or somewhere else more convenient.

Antibiotic-resistant tuberculosis (TB)

Like most bacteria, bacteria that cause TB can develop a resistance to antibiotics. This means the medicines can no longer kill the bacteria they are meant to fight.

Tuberculosis (TB) that develops a resistance to one type of antibiotic is not usually a concern because alternative antibiotics are available. In 2011, more than eight out of 100 cases of TB were resistant to at least one type of antibiotic normally used to treat the condition. 

However, in a number of cases:

• TB develops a resistance to two antibiotics – this is known as multi-drug resistant tuberculosis (MDR-TB) 
• TB develops a resistance to three or more antibiotics – this is known as extensively drug resistant tuberculosis (XDR-TB)

In 2011, almost two out of every 100 TB cases were resistant to at least two antibiotics. 

Both MDR-TB and XDR-TB will usually require treatment for at least 18 months using a combination of different antibiotics. As these conditions are difficult to treat, you may be referred to a specialist TB clinic for treatment and monitoring.

Preventing the spread of infection

If you are diagnosed with pulmonary tuberculosis (TB), which affects the lungs, you will be contagious up to about two to three weeks into your course of treatment.

You will not normally need to be isolated during this time, but it is important to take some basic precautions to stop TB spreading to your family and friends. These precautions are:

• stay away from work, school or college until your TB treatment team advises you it is safe to return 
• always cover your mouth when coughing, sneezing or laughing 
• carefully dispose of any used tissues in a sealed plastic bag 
• open windows when possible to ensure a good supply of fresh air 
• do not sleep in the same room as other people because you could cough or sneeze in your sleep without realising it