What is TB
It is an infectious disease caused by a pathogenic Aerobic bacteria namely Mycobacterium tuberculosis belonging to the family mycobacteriaceae. It causes death of patients affected with TB. Mycobacterium has an unusual structure consisting of waxy surface on the the cell wall due to the coating of cell wall with Mycolic acid, which is along chain fatty acid responsible for growth and survival of the mycobacterium species. Primary organ going to be affected will be lungs as the organism get deposited onto the alveolar spaces of lungs. Slowly other parts like bone, Central Nervous system and other parts will be affected.
It is the world’s deadliest diseases included in top ten causes of death. About One-third population have been affecting with TB. Out of 10.4 million people fell ill with TB, there were 1.7 million TB- related deaths have been occured worldwide (including HIV). Over 95% of TB deaths occurs in low and middle income countries. In 2016, 40% of HIV deaths are due to TB. Multidrug Resistant Tb has remains a public health crisis, as most of the TB cases are resistant to the first line of drug rifampicin.
Globally the incidence of TB has been falling by 2% per year. It has to reach 4-5% to decline TB cases annually.
Types of TB
Mainly Mycobacterium infection is of two kinds of which one is harmful and the other is harmless. TB germs are dormant and inactive in the body. Sometimes the dormancy phase lasts for even decades. This bacteria reproduce and spreads causing tissue damage. Tuberculosis usually affects the lungs causing pulmonary tuberculosis. Thus different types of tuberculosis infections have been classified based on the organ or part of the body affected.
- Latent TB – Mycobacterium remains in the body but in inactive state. It does not produce any sick symptoms and is not infectious or contagious, but they may become active. If not diagnosed and treated, about 5-10% of infected persons will develop TB at sometime of their lives.
- Active TB – It occurs when our Immune system is unable to stop the bacteria from its growth and reproduction. The activated mycobacterium begin to multiply in the body and causes tuberculosis. Firstly it affects the lungs and can make a hole through them causing pulmonary TB. Active TB occurs immediately after the infection, even before the Immune system come into action to fight against the bacteria. Sometimes weak immune system is resoponsible for the infection.
Etiology and Risk factors
- Tuberculosis is caused by mycobacterium tuberculosis, an Aerobic bacterium is the major cause of TB prevalence.
- The cell wall component of mycolic acid, a fatty acid is another cause of the Tb infection.
- Weak Immune system which cannot fight against mycobacterium.
- HIV Infected persons are more suspectible to TB.
- During Organ transplantation, due to the use of Immunosupressant drugs to prevent rejections.
- Persons with Diabetes are susceptible.
- Smoking, Tobacco use increases the incidence of infection.
- Alcohol intake is a high risk factor for TB.
- Low socio-economic status.
- Prolonged Corticosteroid therapy.
- Recent TB Infection.
- Health care workers dealing with TB patients.
- Crowded living conditions.
- Mycobacterium transmits through droplet infection and enters the lungs and reaches alveoli when inhaled. It causes pulmonary tuberculosis.
- Tubercle bacilli multiplies rapidly in the spaces of alveoli and spreads the the infection throughout the respiratory tract.
- Slowly it starts dividing and affects other parts of the body like bone causing Joint pains, kidneys causing Renal failure, brain causing Meningitis.
- The immune cells like Macrophages, will control the bacilli and makes them Inactive or dormant.
- Whenever the mycobacterium gets activated, it breaks off the macrophage layers and multiply spreading the infection throughout the body.
Signs and Symptoms
- Chest pain due to the primary infection to lungs.
- Chronic Cough lasting more than 3 months.
- Pain during coughing and blood may be observed during coughing.
- Swollen lymph nodes as the mycobacteria targets and destroys Immune cells.
- Swollen throat might be due to infection to tonsils.
- Blood in sputum
- Fatigue and weakness may be observed.
- Fever with very high temperature lasting for days.
- Weight loss
- Night sweats
- Pain in joints
- A Positive Mantoux Tuberculin skin test to detect tuberculosis infection.
- Tuberculin test sometimes will be positive when the person was recently vaccinated.
- A positive skin test must be confirmed by Chest radigraph or X-ray or CT Scan.
- Blood test can be done to confirm the phase of mycobacterium, either in latent phase or Active phase.
- Sputum Test to confirm the active mycobacterium in the mucous.
- If symptoms similar to TB, immediately consult doctor and confirm through diagnosis. The first line drugs used to treat TB are INH (Isoniazid), Rifampicin, Pyrizinamide, Ethambutol etc.,
- In Multidrug resistant tuberculosis infection, the mycobacterium becomes resistant to first line drug treatment with Isoniazid and Rifampicin.
- MDR TB can be treated by high dose Anti-Tubercular drugs like INH, rifampicin, with the combinations of Antibiotics like flouroquinolones and Aminoglycosides etc.,
- Antibiotics like high dose-Levofloxacin and Amikacin, Kanamycin will be prescribed in combinations.
- TB vaccine, Bacille Calmette-Guerin (BCG) has to be taken to prevent the infection.
- If any related symptoms appear, diagnose immediately and start taking treatment as early as possible.
- Maintain good hygeinic conditions.
- Intake of nutritious diet to activate our Immune system.
- Maintain Healthy life style and Environment.