- Worldwide, tuberculosis (TB) has surpassed HIV-AIDS as the leading cause of death due to infectious diseases.
- India contributes to 27% of the global TB burden, the highest share globally.
- As per WHO, an estimated 4.5 lakh people have MDR-TB and nearly 37,500 people have XDR-TB.
- Out of these, India has 24% of MDR-TB cases in the world.
- Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis.
- TB commonly affects the lungs (pulmonary TB) but can also affect other parts (extrapulmonary TB).
- Pulmonary tuberculosis is a chronic consumptive disease, but it can be present as acute pneumonia.
- Pneumonia is an inflammatory condition of the lung affecting primarily the microscopic air sacs known as alveoli.
- Tuberculosis spreads from person to person through the air, when people who are infected with TB infection cough, sneeze or otherwise transmit respiratory fluids through the air.
- The most common risk factor associated with TB is HIV & other conditions that impair the immune system.
Tuberculosis Symptomatic Diagnosis
- Most infections do not have symptoms, known as latent tuberculosis.
- About 10% of latent infections eventually progresses to active disease which, if left untreated, kills about half of those infected.
Common symptoms of tuberculosis are:
- Chronic cough with blood-tinged sputum,
- Loss of weight,
- Loss of appetite,
- Fever and night sweats,
- Fatigue , etc.
- The standard 6-month course treatment consists of 2 phases:
- 1st phase – It lasts for 2 months and is called Intensive phase.
- 2nd phase – It lasts for 4 months and is called Continuous phase.
- For new TB cases, the treatment in intensive phase (IP) consists of four drugs:
- Isoniazid (INH),
- Pyrazinamide &
- For previously treated cases of TB, the intensive phase is of 12 weeks, where injection streptomycin is given for eight weeks along with four drugs.
- Most people with TB are cured by a strictly followed 6-month drug regimen.
Multidrug-Resistant TB (MDR-TB)
- CBNAAT (Cartridges Based Nucleic Acid Amplification Test) is used for early diagnosis of MDR-TB.
- In MDR-TB, the bacteria that cause TB develop resistance to antimicrobial drugs used to cure the disease.
- MDR-TB does not respond to at least isoniazid and rifampicin, the 2 most powerful anti-TB drugs.
- Treatment options for MDR-TB are limited and expensive.
- In some cases, even more severe drug-resistant TB may develop.
Extensively Drug-Resistant TB (XDR-TB)
- XDR-TB is a form of multidrug-resistant TB with additional resistance to more anti-TB drugs.
- People who are resistant to isoniazid and rifampicin, plus any fluoroquinolone and at least one of three injectable second-line drugs (amikacin, kanamycin, capreomycin) are said to have XDR-TB.
Causes of Multidrug Resistant-TB
- Multidrug resistance is caused due to mismanagement of treatment & person-to-person transmission.
- Mismanagement of TB treatment involves inappropriate or incorrect use of antimicrobial drugs or use of ineffective formulations of drugs and premature treatment interruption.
Treatment for Drug-Resistant TB
- The treatment success in MDR-TB patients is about 54%, while it is just 30% in the case of XDR-TB patients.
- A combination of eight drugs for more than a year is need for XDR-TB treatment.
- Treatment success in XDR-TB patients depends on the extent of the drug resistance, the severity of the disease, whether the patient’s immune system is weakened, and adherence to treatment.
- Drugs used for treating MDR-TB and XDR-TB can cause serious adverse effects such as deafness.
New Promising Drug Pretomanid
- Treating MDR-TB and XDR-TB could get simpler and shorter with the new drug Pretomanid.
- Pretomanid is only the third anti-TB drug approved by U.S. FDA in more than 40 years.
- The drug was developed and tested by New York-based non-profit organisation TB Alliance.
What makes Pretomanid promising?
- The duration of treatment for drug-resistant TB can be cut from 18-24 months to just six-nine months when three-drug regimen consisting of Bedaquiline, Pretomanid and Linezolid (BPaL regimen) is used.
- The all-oral, three-drug regimen can vastly improve the treatment success rate & adherence to treatment.
- Importantly, the regimen was found to be safe and effective in curing TB in people living with HIV.
- Unlike bedaquiline, which is expensive, pretomanid might become affordable.
Which category of drug-resistant TB patients will benefit from this new drug?
- BPaL regimen is meant for treating adults with XDR-TB.
- In the case of MDR-TB, the three-drug regimen containing pretomanid can be used only in those patients who cannot tolerate the MDR-TB treatment or do not respond to standard MDR-TB treatment regimen.
- The three-drug regimen is meant only for treating pulmonary TB and should not be used for treating extra-pulmonary TB, drug-sensitive or latent TB.
What are the adverse reactions caused by the drug?
- The three-drug regimen was reported to have caused adverse reactions including liver toxicity (hepatotoxicity), suppression of bone marrow leading to reduced production of red & white blood cells & platelets, etc.
- Revised National TB Control Programme was renamed as the National TB Elimination Programme (NTEP).
- The change in name is in line with the larger goal of eliminating the disease by 2025, five years ahead of the Sustainable Development Goals target of 2030.
- 1962: The National TB Programme (NTP) was launched by GOI with BCG vaccination at the district level.
- 1993: WHO declared TB as a global emergency and devised the directly observed treatment (DOTS).
- 1993: GOI revitalized NTP as Revised National TB Control Programme (RNTCP).
- 1997: DOTS was launched as the RNTCP strategy. By 2006 the entire country was covered under RNTCP.
- In its second phase (2006–11), RNTCP improved the quality and reach of services.
- Despite the measures, undiagnosed and mistreated cases continued to drive the TB epidemic.
- A large number of MDR-TB cases were reported every year.
- To address this, National Strategic Plan for Tuberculosis Control 2012-2017 was documented with the goal of ‘universal access to quality TB diagnosis and treatment’.
- Significant interventions were taken during NSP 2012-2017 in terms of mandatory notification of all TB cases, integration of the programme with the National Health Mission, etc.
- To eliminate TB in India by 2025, National Strategic Plan for Tuberculosis Elimination 2017-2025 involving all the stakeholders was formulated by RNTCP.
- On 01-01-2020, RNTCP was renamed as National TB Elimination Programme (NTEP).
National strategic plan for tuberculosis elimination (NSP) 2017-2025 (NSP)
- TB elimination has been integrated into the four strategic pillars of “Detect – Treat – Prevent – Build” (DTPB).
- Early diagnosis and treatment of TB is an important step in TB elimination.
- The objective of NSP was to find all drug sensitive TB cases (DS-TB) and drug resistant TB cases (DRTB).
- To facilitate TB notification, RNTCP has developed a TB surveillance system called “NIKSHAY” (https://nikshay.gov.in) for both government and private health care facilities.
- For TB diagnosis more than 14,000 designated microscopy centres spread across the country.
- Cartridge Based Nucleic Acid Amplification Tests (CBNAAT) / Line Probe Assay (LPA) has been established at district levels for decentralised molecular testing for drug resistant TB.
- From 2020, GOI will be using Truenat test as a part of early-stage diagnosis.
- Screening of all patients for rifampicin resistance (and for additional drugs wherever indicated) is done.
- For drug sensitive TB, daily fixed dose combinations (FDCs) of first-line anti-tuberculosis drugs is given.
- Isoniazid Preventive Therapy (IPT) is given to children who are close contacts of a TB patient.
- BCG vaccination is provided at birth or as early as possible till one year of age.
- BCG vaccine has a protective effect against meningitis and disseminated TB in children.
- Health system strengthening for TB control under the NSP 2017-2025 is recommended in the form of building and strengthening enabling policies, empowering institutions, and human resources.
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