What is tuberculosis ?(TB)
TB is an infectious bacterial disease caused by Mycobacterium tuberculosis. It commonly affects the lungs but can infect any tissue of the body, for example the spine, bones, brain and lymph nodes.

How do you get TB?

People get infected following inhalation of infected particles of air. The infection is transmitted from person to person especially by coughing, sneezing or spitting. Individuals are particularly infectious when they are coughing up sputum.

What are the symptoms of TB?

Common symptoms are cough with sputum, coughing up blood, fever, weight loss and night sweats. Because TB is slow growing, the symptoms are often slow and gradual in onset. This means that patients do not seek medical advice immediately and when they do so, a high index of suspicion is required  by the doctor. Joint and bone tuberculosis diagnosis is often delayed for this reason.

How is TB diagnosed?

For pulmonary TB, sputum is examined under a light microscope and then cultured for several weeks. Alternatively, in extra-pulmonary TB, tissue from the relevant site is biopsied (eg lymph node) for a similar same investigations.

Treatment of TB

Four drugs are usually adminstered for 6 months. In some forms of TB, such as TB of the nervous system, treatment is required for 12 months. The four drugs are Rifampicin, Isoniazid, Pyrazinamide and Ethambutol, although additional drugs are required for multi-drug resistant TB.

How effective is the BCG vaccine?

The BCG vaccine is mostly  effective in protecting children against certain forms of TB such as disseminated ('miliary') TB or TB meningitis. Thus prior BCG vaccination does not mean you cannot get TB, especially in adults.