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Symptoms of TB

Tuberculosis (TB) is an infection caused by a germ called the tubercle bacillus or mycobacterium tuberculosis. It can affect the lungs (pulmonary TB) or other parts of the body, such as the lymph nodes (tuberculous adenitis or scrofula), the skin and the bones.

TB is a contagious disease. Like the common cold, it spreads through the air. Only people who are sick with TB in their lungs are infectious. When infectious people cough, sneeze, talk or spit, they propel TB germs, known as bacilli, into the air. A person needs only to inhale a small number of these to be infected.

Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year. But people infected with TB bacilli will not necessarily become sick with the disease. The immune system "walls off" the TB bacilli which, protected by a thick waxy coat, can lie dormant for years. When someone's immune system is weakened, the chances of becoming sick are greater.

Typical symptoms of active tuberculosis

  • A persistent cough, with and without phlegm (coughed-up mucus)

  • Night sweats and fever

  • Weight loss

  • Coughing up blood

  • Persistent lymph gland swelling

Patients with these symptoms should contact their GP (doctor) without delay to be assessed and referred if necessary.

What if I have been in contact with someone with TB?

Discuss this with your family doctor. Only close contacts are at risk of catching TB. You may be asked to make an appointment with your local chest clinic. Sometimes a TB nurse or chest diseases health visitor will contact you first (they will have a list of close contacts). The nurse will arrange a Tb specific blood test and/or chest x-ray. This does not mean that you have active TB, but it is a chance to check for any symptoms, so it is very important that you do attend, if asked.


TB questions and answers - from the Health Protection Agency

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