Tuberculosis (TB)

Dr. Amany Ayub MBBS,


Public Health Specialist Global Scenario

Tuberculosis TB is the 13th leading cause of death worldwide and the second leading infectious killer after COVID-19 (above HIV/AIDS). In 2020, an estimated 10 million people will fall ill with tuberculosis (TB) worldwide. 5.6 million men, 3.3 million women, and 1.1 million children. TB is present in all countries and age groups. The WHO report, titled “Global Tuberculosis Report 2021”, released on October 14, shows that India accounted for 41% of the total global drop of 1.3 million. This is when the country shares the world’s highest burden of tuberculosis, a communicable disease.

Tuberculosis (TB)

Bangladesh Scenario

Tuberculosis (TB) is a major public health problem in Bangladesh. According to the World Health Organization’s Global TB Report 2018, Bangladesh ranks among 30 high TB-burden countries and accounts for 3.6% of the global total. The estimated incidence of TB per 100,000 is 221 in Bangladesh, with a mortality rate of 24 per 100,000 population. Approximately 80% of all TB cases in Bangladesh are pulmonary TB. The Global TB Report 2020 says that 0.7% of new cases and 11% of people who have been treated for TB already have multidrug-resistant TB (MDR-TB), which has a rate of 2.0 per 100,000 people in Bangladesh.

Tuberculosis (TB)

TB disease

Tuberculosis is caused by Mycobacterium tuberculosis bacteria that spreads from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs, or sings.

Most TB diseases occur in the lungs. Therefore, a person with TB of the lungs usually has a productive cough that is sometimes bloodstained.

  • General symptoms of TB disease include a prolonged cough that produces sputum that lasts more than two weeks, fever, chest pain, sweating at night, loss of appetite, weight loss, and fatigue.
  • Extrapulmonary:

In 15–20% of active cases, the infection spreads outside the lungs, causing other kinds of TB. These are collectively denoted as extrapulmonary tuberculosis. Extrapulmonary TB occurs more commonly in people with a weakened immune system and young children. In those with HIV, this occurs in more than 50% of cases.

Tuberculosis (TB)

Notable extrapulmonary infection sites include the pleura (in tuberculous pleurisy), the central nervous system (in tuberculous meningitis), the lymphatic system (in scrofula of the neck), the genitourinary system (in urogenital tuberculosis), and the bones and joints (in Pott disease of the spine), among others. A potentially more serious, widespread form of TB is called “disseminated tuberculosis,” also known as miliary tuberculosis. Miliary TB currently makes up about 10% of extrapulmonary cases.

TB disease can be cured with standard treatment, even in people with HIV infection. However, untreated TB is often fatal, especially in people infected with HIV.

Tuberculosis (TB)

Tuberculosis complications include

  • Spinal pain Back pain and stiffness are common complications of tuberculosis.
  • Joint damage Arthritis that results from tuberculosis (tuberculous arthritis) usually affects the hips and knees.
  • Swelling of the membranes that cover your brain (meningitis). This can cause a lasting or intermittent headache for weeks and possible mental changes.
  • Liver or kidney problems Your liver and kidneys help filter waste and impurities from your bloodstream. However, tuberculosis in these organs can impair their functions.
  • Heart disorders Rarely, tuberculosis can infect the tissues surrounding your heart, causing inflammation and fluid collections that might interfere with your heart’s ability to pump effectively. This condition, called cardiac tamponade, can be fatal.

Factors that determine the likelihood of transmission

Tuberculosis (TB)

The chance that a person who is exposed to TB bacilli will become infected is mainly determined by:

  1. The amount of infectious droplet nuclei in the air is affected by how many organisms the TB patient makes and how much ventilation is in the area exposed to the atmosphere.
  2. The duration of exposure to the infectious droplet nuclei
  3. The proximity to the source of infectious droplet nuclei (as well as the organism’s virulence)
  4. The immune status of the exposed individual

Host characteristics

The characteristics of people exposed to TB bacilli that may affect the risk of becoming infected are the following:

  • People who have HIV or take immunosuppressive drugs may be more likely to get TB infections and have early TB disease if they are exposed.
  • TB infection is the strongest known risk factor for TB to TB disease progression.
  • People who use tobacco or alcohol may also be at an increased risk of infection and disease.
  • People with chronic diseases, for example, malnutrition, diabetes, and chronic diseases,

Features of TB patients that may enhance their ability to infect others

The probability that a TB patient is infectious depends on:

  • presence of the disease in the lungs (pulmonary TB), airways, or larynx.
  • The presence of a cough or other forceful exhalation
  • presence of acid-fast bacilli (AFB) in the sputum.
  • When someone coughs or sneezes, they should cover their mouth and nose. This is called “poor cough etiquette.”
  • Patients who received inappropriate or short-term chemotherapy did not follow national guidelines.
  • Undergoing procedures can induce coughing or cause aerosolization of M. tuberculosis (e.g., sputum induction, bronchoscopy).

Environmental factors that enhance the likelihood of transmission

  • exposure in enclosed, relatively small, poorly ventilated spaces.
  • Inadequate ventilation to “clean” the environment through dilution or removing infectious droplet nuclei.
  • Re-circulation of air containing infectious droplet nuclei.

Risk factors for health care workers

  • My work involves the diagnosis and treatment of TB patients.
  • Work involves cough-inducing procedures like sputum induction intubation.
  • I work in environments with limited or no infection control practices in place.
  • Frequent and direct contact with (sputum or culture-positive) TB patients
  • Duration of contact with (sputum or culture-positive) TB patients
  • Frequent contact with (sputum or culture positive) TB patients who have not yet been
  • started on treatment.
  • HIV-positive health care workers

Tuberculosis Tests and Diagnosis

  1. Skin test: This is also known as the Mantoux tuberculin skin test. A technician injects a small amount of fluid into the lower arm’s skin. After 2 or 3 days, they’ll check for swelling in the lower arm. If the result is positive, it probably has TB bacteria. But patients could also get a false positive. For example, if the patient has had a tuberculosis vaccine called bacillus Calmette-Guerin (BCG), the test could say that the patient has TB when they don’t. On the other hand, the results can also be false negative, saying that the patient doesn’t have TB if it is a very new infection. Patients might get this test more than once.
  2. A chest X-ray or CT scan to look for changes in the lungs
  3. Sputum microscopy for TB is one of the most efficient tools for diagnosing people with infectious TB, monitoring treatment progress, and confirming that cure has been achieved. Unfortunately, sputum in the early morning often has more M. tuberculosis.
  4. Test for several infectious diseases, including TB and COVID-19. WHO recommended that the test be used as the initial diagnostic test in individuals suspected of having MDR-TB or HIV-associated TB.

4.   Conduct multiple infectious disease tests, including tuberculosis and COVID-19. The WHO recommends that the test be used as a screening test in individuals suspected of having MDR-TB or HIV-associated tuberculosis.

Tuberculosis Treatment

Treatment will depend on the infection.

  • A combination of medicines for treating active TB The most common are rifampicin, isoniazid, pyrazinamide, and ethambutol for 6 to 12 months.
  • The doctor might give one or more different medicines to take for much longer, up to 18 to 24 months, for drug-resistant TB. If treatment lasts too long, it can be hard to stay on track, cost more money, and cause more harm than good.

Whatever the infection, it’s important to finish taking all medications, even when the patient feels better. If the patient stops medications too soon, the bacteria can become resistant.

Like any medication, TB drugs can have side effects

Common rifampicin side effects include:

  • skin rash
  • Upset stomach, nausea, and vomiting
  • Diarrhoea
  • Loss of appetite
  • Inflamed pancreas 

Common isoniazid side effects include:

  • Numbness and tingling in your hands and feet.
  • Upset stomach, nausea, and vomiting
  • Loss of appetite
  • weakness. 

Some pyrazinamide side effects include:

  • Lack of energy
  • Nausea and vomiting
  • Loss of appetite
  • Muscle or joint pain

Ethambutol side effects may include

  • Chills
  • Swollen or painful joints
  • Belly pain, nausea, and vomiting
  • Loss of appetite
  • Headache
  • Confusion

Tuberculosis Prevention

There are many ways to prevent tuberculosis. For example, in children, the tuberculosis vaccine is administered to avoid TB infection in the future. The vaccine is called the BCG vaccine, or the Bacille Calmette Guerin vaccine.

To help stop the spread of TB,

  • If you have a latent infection, take your medication to become active and contagious.
  • If you have active TB, limit your contact with other people. Cover your mouth and nose when coughing or sneezing.
  • Wear a surgical mask when you’re around other people during the two weeks of treatment.
  • If you’re travelling to a place where TB is common, practice physical distancing by avoiding unnecessary travel and staying away from large groups of people.

Prognosis of Tuberculosis

Generally, people who receive timely treatment and complete the course without missing the medications do very well. In addition, the recurrence rate of tuberculosis is quite low and ranges from 0 to 14%. However, those who have had tuberculosis in the past and have had reactivation reinfection do not necessarily have an excellent long-term outcome. Similarly, tuberculosis that affects elderly individuals or poor immunity does not work very well either.

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