Tuberculosis

TB is one of the leading cause of death in India after HIV/AIDS.

1. TUBERCULOSIS PRESENTED BY: CH.BINDU MADHAVI NCPA

2. DEFINITION: A specific disease caused by infection with Mycobacterium tuberculosis , the tubercle bacillus, which can affect almost any tissue or organ of the body, the most common site of the disease being the lungs. The bacteria that cause tuberculosis are spread from one person to another through tiny droplets released into the air via coughs and sneezes.

3. CLASSIFICATION: Class Type Description No TB exposure Not infected No history of exposure Negative reaction to  tuberculin  skin test 1 TB exposure No evidence of infection History of exposure Negative reaction to tuberculin skin test 2 TB infection  No disease Positive reaction to tuberculin skin test No clinical, bacteriologic, or radiographic evidence of TB 3 TB, clinically active M. tuberculosis  cultured (if done) Clinical, bacteriologic, or radiographic evidence of current disease 4 TB  Not clinically active History of episode(s) of TB  Positive reaction to the tuberculin skin test. No clinical or radiographic evidence of current disease. 5 TB suspect Diagnosis pending TB disease should be ruled in or out within 3 months

4. There are two types of TB Based on symptoms: latent and active . ACTIVE TB: Active TB is an illness in which the TB bacteria are rapidly multiplying and invading different organs of the body. The typical symptoms of active TB variably include cough, phlegm, chest pain, weakness, weight loss, fever, chills and sweating at night . LATENT TB: Many of those who are infected with TB do not develop overt disease. They have no symptoms and their chest x-ray may be normal. The only manifestation of this encounter may be reaction to the tuberculin skin test (TST) or interferon-gamma release assay (IGRA). 

5. T here are two types of tuberculosis: the “ open” or pulmonary-positive or pulmonary tuberculosis and “closed ” or pulmonary-negative tuberculosis also called as extra pulmonary tuberculosis.  In the case of pulmonary tuberculosis an inflammation developed inside the lungs that the immune system is not able to isolate, i.e., bring under control. This enables TB bacteria to be released through the respiratory tract (e.g., through coughing) and means that this type of tuberculosis infection is contagious .  I n case of extra pulmonary tuberculosis organs that are affected by the bacteria – most commonly the lymph nodes, but also the bones and joints, spine, intestines, kidneys or brain .As with the closed tuberculosis, EP tuberculosis is not contagious.

6. EPIDEMIOLOGY: India is the country with the highest burden of TB. The World Health Organisation (WHO) TB statistics for India for 2016 give an estimated incidence figure of 2.79 million cases of TB for India . In India, each year, approx. 2,20,000 deaths are reported due to Tuberculosis between 2006 and 2014. This public health problem is the world's largest tuberculosis epidemic. Tuberculosis is the second-most common cause of death from infectious disease (after those due to HIV/AIDS).

7. MORPHOLOGY: Mycobacterium tuberculosis , the causative agent of tuberculosis, is an oblong, bacillus-type bacterium that grows and multiplies within cells which belongs to the family  Mycobacteriaceae . It is acid-fast strain .   Acid fast  stains such as  Ziehl-Neelsen , or  fluorescent  stains such as  auramine  are used instead to identify  M. tuberculosis with a microscope. The physiology of  M. tuberculosis  is highly aerobic and requires high levels of oxygen.  Mycobacterium tuberculosis is slow-growing and typically requires up to six weeks to form visible colonies in laboratory cultures.

8. ZIEHL NEELSEN METHOD AURAMIN METHOD

9. Over half of the cell wall of Mycobacterium tuberculosis is lipid, creating a protective water-resistant shell around the bacteria. Mycobacterium tuberculosis enters hosts via inhalation from the air. After inhalation the bacteria enter a type of white blood cell known as a macrophage. Macrophages normally locate and destroy pathogens in the body, but Mycobacterium tuberculosis is able to live and multiply inside the cells without being destroyed. The incubation period may vary from about 2 to 12 weeks. 

10. ETIOLOGY: Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air.

11. Risk factors: Factors that increase the risk of the disease. Weakened immune system : A number of diseases, conditions and medications can weaken immune system, includes: HIV/AIDS Diabetes Severe kidney disease Travelling or living in certain areas: The risk of contracting tuberculosis is higher for people who live in or travel to areas that have high rates of tuberculosis and drug-resistant tuberculosis. Lack of medical care. Substance use:  Use of IV drugs or excessive alcohol weakens your immune system and makes more vulnerable to tuberculosis. Tobacco use: Using tobacco greatly increases the risk of getting TB and dying of it.  

12. PATHOPHYSIOLOGY:

13. CLINICAL PRESENTATIONS: A bad cough that lasts 3 weeks or longer Pain in the chest Coughing up blood or sputum Weakness or fatigue Weight loss No appetite Chills Fever Sweating at night

14. COMPLICATIONS: Spinal pain Joint damage Swelling of the membranes that cover your brain (meningitis). Liver or kidney problems .

15. LAB TESTS: BLOOD TESTS: Blood tests may be used to confirm or rule out latent or active tuberculosis.  SPUTUM TESTS: The samples are tested for TB bacteria . Sputum samples can also be used to test for drug-resistant strains of TB M. tuberculosis (stained red ) in sputum CULTURE TESTS: Mycobacterium tuberculosis are called acid-fast bacilli (AFB) because after an acid wash the bacteria retain the colour of the stain. They can then be seen under the microscope

16. DIAGNOSTIC TESTS: chest X-ray: if the germ has attacked and caused inflammation in the lungs, an abnormal shadow may be visible on the chest X-rays. CT scan: an imaging test to check lungs for signs of an infection

17. MANTOUX TEST: A tuberculin skin test, also known as a Mantoux test or PPD (purified protein derivative), is done by injecting a solution containing a protein made from tuberculosis bacteria just under the top layer of skin on the fore arm. If the skin at the injection site develops a raised red bump, it indicates that the person may be infected with TB.

18. TREATMENT: Most common TB drugs Isoniazid Rifampin (Rifadin, Rimactane) Ethambutol (Myambutol) Pyrazinamide Bedaquiline (Sirturo) Linezolid (Zyvox) Active TB disease is best treated with combinations of several antibiotics to reduce the risk of the bacteria developing antibiotic resistance. First-line drugs used to treat active TB are isoniazid, Rifadin,  ethambutol ( Myambutol), and  pyrazinamide .

19. Latent TB Infection Treatment Regimens Drugs Duration Interval Minimum Doses Isoniazid 9 months Daily or Twice weekly 270 76 Isoniazid 6 months Daily or Twice weekly 180 52 Isoniazid and Rifapentine 3 months Once weekly 12 Rifampin 4 months Daily 120

20. TREATMENT FOR PULMONARY TB: isoniazid , rifampicin, pyrazinamide, ethambutol, and streptomycin - are recommended for the initial 3 to 4 months. TREATMENT FOR EXTRA PULMONARY TB: Same combination of antibiotics are used . In case of brain TB corticosteroids such as prednisolone for several weeks along with antibiotics is prescribed to reduce swelling in affected areas.

21. VACCINES: The only available vaccine as of 2011 is Bacillus Calmette-Guérin (BCG). In children it decreases the risk of getting the infection by 20% and the risk of infection turning into active disease by nearly 60%. It is the most widely used vaccine worldwide, with more than 90% of all children being vaccinated. The immunity it induces decreases after about ten years.

22. PREVENTION: Stay home.   Ventilate the room . Cover your mouth.   Wear a mask Finish your entire course of medication Vaccinations

23. REFERENCES: www.medicinenet.com www.wedmd.com www.nationaljewish.org www.ncbi.nlm.nih.gov www.sciencedirect.com www.mayoclinic.com Ananthanarayana textbook page no: 351-363 www.webmd.com www.webmd.com

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