To be aware of latent TB, is it necessary to take medication?

Tuberculosis (TB) is an infectious disease that infects the lungs. Tuberculosis transmission occurs when the sufferer coughs or sneezes and the fluids that are expelled are inhaled by people around them through the air. However, not everyone who is infected will experience symptoms of tuberculosis. It could be that he is in a latent TB condition so that he doesn't show any signs. So, what is the difference between latent TB and active TB? Do you both need treatment? Check out the explanation below.

What is latent TB?

Tuberculosis (TB) is a deadly disease caused by bacteria Mycobacterum tuberculosis. Based on data from the World Health Organization (WHO), tuberculosis is in the top 10 causes of human death in the world, above HIV / AIDS. Per year, about 1.5 million people die from tuberculosis.

Latent TB is a TB infection that is asymptomatic, aka asymptomatic. Yes, even though they are infected with the bacteria that cause tuberculosis, they do not show symptoms in the form of a cough which is common in tuberculosis sufferers.

This condition is also known as inactive Tb. A person with latent or inactive TB conditions may not know they have TB because they do not feel sick or have respiratory problems like people with active TB.

The condition of latent TB is influenced by an immune response that is resistant to bacterial infection. People with inactive TB cannot pass the bacteria to other people. This condition also cannot be read from the initial TB examination with a skin test.

Causes of latent TB infection

The condition of tuberculosis without symptoms (latent TB) is caused by tuberculosis bacteria that enter the body in a dormant state or are not actively infecting. That is, the bacteria do not multiply and cause damage to healthy lung cells, the "sleeping" eyebrows.

In the book Tuberculosis , it is written that there are 3 stages of TB bacterial infection, namely primary infection when the bacteria enter the body, latent infection, and active infection — when the active bacteria multiply. Latent infection can keep bacteria dormant for years in the body. This condition indicates latent TB.

The immune system that works optimally when transmission takes place and the minimum number of bacteria that enter causes TB bacterial infection can be resisted so that it does not cause any health problems.

Macrophages, which are white blood cells that are in the immune system's first line of resistance, successfully form a protective wall called a granuloma. Granuloma is what keeps the TB bacteria from infecting the lungs.

However, if one time the immune system condition is weakened, these sleeping bacteria can "wake up" and turn into active TB.

Is there a test for latent TB?

The condition of latent TB cannot just be known. To detect it, one needs not only to do a skin test, namely the tuberculin test (Mantoux test).

The results of a more definite diagnosis can only be obtained by carrying out more complete examinations, such as blood tests and chest X-rays.

1. Tuberculosis skin test

The tuberculosis skin test is also called the Mantoux tuberculin skin test (TST). The skin test is done by injecting a fluid called tuberculin into the skin on the underside of the arm. The results of this test are limited to showing whether you are infected with TB bacteria or not. Active or inactive infection cannot be determined.

2. Blood test

The blood test for TB is also known as the interferon-gamma release test (IGRA). This test is done after a skin test shows a positive result. In principle, the IGRA test works by detecting one of the cytokines, interferon-gamma, in a blood sample that can indicate an immune system response to a bacterial infection.

3. Sputum smear microscopy

This examination is also known as a sputum test or BTA (acid-resistant bacilli). The aim of the BTA examination is to analyze the sputum sample under a microscope to detect the presence and amount of TB bacteria. The level of accuracy of this test is greater than the TB skin test.

4. Lung X-rays

X-rays aim to complete the diagnosis from the results of skin and sputum tests. X-rays of the lungs can show signs of lung damage caused by tuberculosis bacterial infection.

Who is at high risk for latent TB?

WHO recommends that several groups of people need to be screened for latent TB, that is, people who are most at risk of developing TB. The following are groups of people with the highest risk factors for TB:

• Adults, teenagers, children and toddlers who live with HIV sufferers need to be checked for TB.
• Toddlers and children under five years of age who have recently had contact with a tuberculosis patient.
• People with weak immune system conditions (immunosuppressants) and often interact with TB sufferers.
• People who have diabetes mellitus and interact with people with tuberculosis.
• Patients starting anti-TNF treatment (Tumor Necrosis Factor) to treat rheumatism, do dialysis (dialysis), and those who are preparing for an organ transplant.
• Health workers, namely doctors and nurses who treat drug-resistant TB (MDR-TB) patients

Apart from this group, the following groups of people also have a lower risk of latent TB, but it is advisable to do TB screening:

• Children over 5 years of age who are HIV-negative.
• Adolescents and adults who come into contact with pulmonary tuberculosis patients and contact with multi-drug resistant tuberculosis patients.
• Prisoners in a prison where there is a tuberculosis outbreak.
• Immigrants from tuberculosis epidemic countries.
• Drug users.

Medications to prevent latent TB from becoming active TB

WHO says, 5-15% of people with latent TB status are at risk of developing active TB. Patients with latent TB with HIV / AIDS are at the highest risk of developing active TB. This can happen when the person's immune system is down, leaving room for bacteria to develop into a more severe state.

Therefore, even if you don't feel the symptoms of tuberculosis, someone with this bacterial infection needs to see a doctor. Unlike patients with active pulmonary TB whose treatment also helps prevent TB transmission, latent TB treatment is carried out to prevent active tuberculosis bacterial infection.

The Centers for Disease Control and Prevention (CDC) recommends several types of antituberculosis drugs for the treatment of latent TB that can be used, namely isoniazid (INH) and rifapentine (RPT).

Treatment is given in daily doses of both drugs which are determined based on the medical condition of each person, the results of the drug's susceptibility to the source of bacterial infection, and the potential for drug interactions with other drugs.

For people with HIV, it usually takes 9 months to prevent the development of latent TB from becoming active. While ordinary latent TB sufferers can recover through this treatment in a shorter time.