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TB

What is TB ?

Tuberculosis (TB) is one of the most serious of infectious diseases and one of the major causes of illness and death worldwide. In the 17th to 19th centuries, when it was commonly known as consumption, it was probably the biggest killer disease of all. Today, it is estimated that a third of the world's population has TB. It is worrying that TB seems to be on the increase in developed countries like the USA and the UK. Tuberculosis can spread to almost any part of the body. Most commonly, TB starts as a small infection in the lung, and very often this is the only part of the body to be affected. Pulmonary (lung) TB is the commonest form of the disease. However, the infection can spread. A particularly severe form of widespread infection is known as miliary TB (galloping consumption). In the early stages, the symptoms of pulmonary TB are similar to those of any other lung infection cough and shortness of breath. In fact, primary TB is often so mild as not to be noticed: it heals up completely, leaving no problems other than a tiny scar on the lung which may be seen on a chest x-ray many years later. If the infection does go on to cause a problem, however, the cough will persist, usually as a troublesome dry cough, and be accompanied by fever, sweats and loss of weight. Sometimes blood may be coughed up. Primary TB usually occurs in childhood, and then heals up, but the TB may recur many years later, as the TB germ lie dormant in the lungs.

How does TB occur ?

A tiny germ named Mycobacterium tuberculosis causes tuberculosis. This germ is usually inhaled in microscopic droplets as a direct infection from somebody else with the disease or absorbed into the gut after drinking infected milk. Pasteurization of milk has reduced the likelihood of getting the infection from contaminated milk.

Why does TB occur ?

TB can only occur as a recurrence from a primary infection some time earlier, or as a direct infection from an infected person or animal. If it is a recurrence, there are certain conditions, which make people more liable to develop TB. For example, people with lowered resistance to disease, such as those who have been treated with chemotherapy drugs for cancer or transplants. There are also some diseases, such as AIDS, diabetes, or silicosis of the lungs which lower resistance to tuberculosis. Lifestyle features, such as alcoholism, drug addiction or conditions of poverty and overcrowding may also contribute.

Treatment involved for TB

Firstly the diagnosis of pulmonary TB has to be confirmed. This can usually be done by a combination of chest x-rays, blood tests, skin tests and examination of the sputum. It is not always easy, and sometimes several weeks may pass before the infection is confirmed. Generally speaking, TB can be cured by drug treatment, and surgery is rarely necessary. However no new drugs have been developed for TB for a long time. As a result of drug resistance to TB (the antibiotics don’t always work) has developed and some people need to be treated with a number of different medicines. The drugs used most frequently are rifampicin, isoniazid, ethambutol and pyrazinamide. Two or more of these drugs are used in combination. They have to be taken for some time - usually recommended for 9 months - in order to rid the body completely of the infection. Rest, fresh air, uncrowded accommodation and good food all help with recovery, and regaining weight. Immunisation with BCG can help to prevent this disease.

During treatment for TB

Anti-TB drugs are very powerful, and occasionally can have side effects that must be recognized. Rifampicin can cause indigestion, and sometimes hepatitis an inflammation of the liver, causing jaundice and sometimes abdominal pain. Less seriously, but alarmingly, it often turns the urine and other body fluids to an orange/red colour! Isoniazid can cause problems with nerves (pins and needles) and muscles, although this rarely happens when a normal diet is eaten. Ethambutol occasionally causes an inflammation at the back of the eye, and any blurring of vision should be reported immediately to the doctor. Regular eye checks may be carried out during treatment with this drug. Pyrazinamide also can cause hepatitis. By using these drugs in combination it is possible to reduce the dosage of each. This in turn reduces the likelihood of suffering side effects.

After treatment for TB

Even when fully treated, it is possible for pulmonary TB to recur sometimes many years later. Always be alert to a recurrence of the same symptoms: dry persistent cough, with loss of weight and sweats.

If TB is left Untreated

It is likely that the infection would worsen, with spread to other parts of the body. People in very robust health, living in good surroundings, may be able to fight off the infection without treatment but then, these are not the people who tend to contract TB anyway. In many countries, the population is protected against TB by immunization with BCG. This is an injection, usually given at the age of around 14, although sometimes given earlier. It makes us produce antibodies that protect against TB infection. It is highly effective but like any treatment, occasionally fails to protect against TB.

Effects on the family of TB

Active or open TB is a highly infectious condition. Family members and close contacts of anybody with active pulmonary TB should always be tested for signs of the infection. This can be done by means of a simple skin test, and usually a chest x-ray. There are a variety of skin tests: the Mantoux, the Heaf and the Tine tests.