Tuberculosis (TB) is one of the most common infections in the world. About 2 billion people are infected with tuberculosis and nearly 3 million of these people die each year. In our country, approximately 70,000 new cases occur each year and, on average, 4,000 deaths.

Cause of Tuberculosis

Tuberculosis is caused by bacteria from the mycobacteria family, mainly Mycobacterium Tuberculosis also known as Koch’s bacillus. It affects various organs in our body, but it primarily targets the lungs, making pulmonary tuberculosis the most common and most relevant for public health, since it is responsible for transmission. Doctors distinguish between two types of tuberculosis infection: latent and active.

  • Latent tuberculosis – the bacteria remain in the body in an inactive state. They do not cause symptoms and are not contagious, but can become active.
  • Active tuberculosis – the bacteria cause symptoms and can be transmitted to other people.

A person with a healthy immune system has only a 10% chance that allows the tuberculosis bacteria to activate and cause symptoms of tuberculosis. If the immune system is weakened due to HIV or other diseases, the risk of progressing from an inactive infection to an active symptomatic disease increases to 70%. Babies, preschool-aged children, pregnant women, and the elderly are also at higher risk of activation due to a weaker immune system.

Causes of Tuberculosis

Although tuberculosis does not spread easily, it is usually transmitted among people who are in close contact (working together or living together). Only people with active tuberculosis infections can spread the bacteria. Coughing, sneezing, even talking can release them into the air and infect other people. Once someone is infected, the bacteria settle in the alveoli and, in most cases, will be contained by the immune system. There are several risk factors that contribute to the development of tuberculosis. Certain groups have a higher risk, such as those who work in hospitals and other areas where people infected with tuberculosis may live, like prisons, nursing homes, homes for HIV patients, or shelters.

Risk Groups

Other potentially susceptible people include:

  • People with diabetes
  • People with head or neck cancer;
  • Diseases that suppress the immune system, such as HIV/AIDS;
  • Kidney disease;
  • People with malnutrition;
  • Medications that suppress the immune system, such as anticancer drugs;
  • Pregnant women;
  • People receiving radiation therapy.

Tuberculosis in Pregnancy

Pregnant women have a 69% higher chance of developing the disease than the rest of the general population. The increased likelihood of contracting the bacteria is related to the weakening of the immune system caused by pregnancy. The treatment of tuberculosis during pregnancy should begin whenever the possibility of the disease is moderate to high. Although the medications used in the treatment of tuberculosis during pregnancy cross the placenta, they do not appear to have harmful effects on the fetus. Newborns of women with untreated tuberculosis during pregnancy may be born underweight and may also contract the disease. The skin test for tuberculosis is considered safe throughout pregnancy. However, the blood test has not been assessed for the diagnosis of tuberculosis infection during pregnancy.

Symptoms of Tuberculosis

There are no symptoms associated with inactive tuberculosis. This means someone could have acquired the bacteria and not yet show any signs of infection. Symptoms only appear when the infection becomes active. They develop gradually and may take several weeks before it becomes evident that something is wrong. The most common include:

  • Cough
  • Weight loss
  • Fatigue
  • Fever
  • Night sweats
  • Chest pain
  • Shortness of breath
  • Loss of appetite

The occurrence of additional symptoms depends on where the disease has spread beyond the chest and lungs. For example, if tuberculosis spreads to the lymph nodes, it can cause swollen glands on the sides of the neck or under the arms. When it spreads to the bones and joints, it can cause pain and swelling in the knee or hip. Genitourinary tuberculosis can cause flank pain with frequent urination, pain or discomfort while urinating, and blood in the urine.

Diagnosis of Tuberculosis

The diagnosis of primary pulmonary tuberculosis is confirmed by a combined analysis of clinical, radiological criteria, and the tuberculin skin test (TST). A skin test allows the doctor to check the immune response to tuberculosis bacteria. The skin test involves an injection into the forearm, which after two or three days, is interpreted by the doctor. If a hard and swollen area develops at the injection site, it means the body has been infected by the bacteria. But this does not necessarily mean that the person has active tuberculosis. Chest X-rays may also be performed and sputum samples can be analyzed in the laboratory. In these cases, the results are used only to rule out or confirm active tuberculosis. The doctor may also suggest other tests to confirm a diagnosis or check for the disease in other parts of the body.

Treatment of Tuberculosis

Antibiotics are used to treat tuberculosis because it is a bacterial infection. Tuberculosis treatment is done on an outpatient basis, for a minimum period of 6 months, daily, without interruption, and should be supervised by the nearest health service, at the patient’s home or workplace. Three or four antibiotics are combined during the first two months of therapy and tuberculosis treatment. Two of these are then given for another four to six months. Depending on the number and type of antibiotics used, as well as the sensitivity pattern of the cultured bacteria, some people may need to take antibiotics for up to 12 months. Most people will take medication every day for the first 2 months, and sometimes weekly for the remaining treatment. It is important to take the medication as the doctor prescribes, and for the full course of treatment. This helps prevent types of tuberculosis bacteria that are resistant to antibiotics, which take longer and are more difficult to treat. If a certain type of tuberculosis infection is resistant to regular antibiotic treatment (a condition known as multi-drug resistant TB or MDR-TB), a combination of different medications for tuberculosis treatment should be taken for 18 to 24 months. Once symptoms disappear, the doctor may re-test the sputum to see if the tuberculosis bacteria are still present. If the disease affects other parts of the body (for example, bones or joints), it may require treatment for more than a year. To prevent the spread of tuberculosis, it is important to get rapid treatment and continue it until completion. This can stop the transmission of bacteria and the emergence of antibiotic-resistant strains. It is important to continue treatment for as long as the doctor recommends. If a person stops taking their medication before the doctor advises, tuberculosis can come back. They may develop active tuberculosis, or the bacteria may become resistant to the medications they are taking.

Is There a Vaccine for Tuberculosis?

The BCG vaccine limits the spread of bacteria after tuberculosis infection. It is given to newborns and reduces the chance of developing severe forms of the disease, such as tuberculous meningitis, but is not effective against pulmonary tuberculosis. It is only available in countries or communities where the risk of tuberculosis infection exceeds 1% per year. In other countries, such as Canada for example, there is controversy over the use of this vaccine, as it is claimed that it does not prevent initial infection.

Prevention of Tuberculosis

Some general measures can be taken to prevent the spread of active tuberculosis: If you are diagnosed with active tuberculosis, you should:

  • Keep your home well-ventilated;
  • When coughing, cover your mouth with a preferably disposable tissue;
  • Wash your hands thoroughly;
  • Spend as much time outdoors as possible;
  • If possible, sleep alone in a separate and properly ventilated room;
  • Do not share cups or cutlery with others;
  • Avoid using public transport, or when using it, wear a mask;
  • Avoid crowds such as shopping malls or nightclubs to prevent spreading the disease

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