DUHS CME - Ojha Institute of Chest Diseases

Tuberculosis

 

 

MODULE 1


Introduction and background

 

Objectives

In this module we will learn about

 

Definition of Tuberculosis (TB)

It is chronic granulomatous inflammatory disease, a highly contagious infection caused by the bacterium called Mycobacterium tuberculosis.
Tubercles (tiny lumps) are a characteristic finding in TB.

 

Treatment of active tuberculosis is mandatory, and should be available free of cost to the patient through the public health system.
It involves a course of anti TB drugs that lasts about six months or more.
 It is important to finish the entire treatment, both to prevent reoccurrence and to prevent the development of drug-resistant tuberculosis.

Although there are millions of new cases of TB each year, not everyone exposed to the bacterium becomes infected nor does everybody infected with it develop clinical symptoms of TB.

Treatment of active tuberculosis is mandatory, and should be available free of cost to the patient through the public health system.
It involves a course of anti TB drugs that lasts about six months or more.
 It is important to finish the entire treatment, both to prevent reoccurrence and to prevent the development of drug-resistant tuberculosis.

Although there are millions of new cases of TB each year, not everyone exposed to the bacterium becomes infected nor does everybody infected with it develop clinical symptoms of TB.

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History of TB

  • Mycobacterium tuberculosis is the bacteria that causes tuberculosis (TB) has been present in the human population since antiquity - fragments of the spinal column from Egyptian mummies from 2400 BCE show definite signs of tuberculosis.
  • The term "phthisis", consumption, appears first in Greek literature. Around 460 BCE, Hippocrates identified phthisis as the most widespread disease of the times, and noted that it was almost always fatal.
  • Exact pathological and anatomical descriptions of the disease began to appear in the seventeenth century. In his Opera Medica of 1679, Sylvius was the first to identify actual tubercles as a consistent and characteristic change in the lungs and other areas of consumptive patients.
  • In 1882, Robert Koch discovered a staining technique that enabled him to see Mycobacterium tuberculosis. What excited the world was not so much the scientific brilliance of Koch's discovery, but the accompanying certainty that now the fight against humanity's deadliest enemy could really begin.
  • Another important development was provided by the French bacteriologist Calmette, who, together with Guerin, used specific culture media to lower the virulence of the bovine TB bacterium, creating the basis for the BCG vaccine, even though relatively ineffective still in widespread use today.
  • Success came in 1943. In test animals, streptomycin, purified from Streptomyces griseus, combined maximal inhibition of M. tuberculosis with relatively low toxicity.
  • On November 20, 1944, the antibiotic was administered for the first time to a critically ill TB patient.

  • Following streptomycin, other Anti-TB agents introduced are
    • Para-aminosalicylic acid (1949)
    • Isoniazid (1952)
    • Pyrazinamide (1954)
    • Cycloserine (1955)
    • Rthambutol (1962) and
    • Rifampin (rifampicin; 1963) were introduced as anti-TB agents
    • Aminoglycosides such as capreomycin, viomycin, kanamycin, and amikacin
    • Quinolones (e.g. moxifloxacin, levofloxin, ofloxacin, and ciprofloxacin) are effective but usually are used in drug resistance situations.
  • Until the 1950s, many people with TB were sent to sanatoriums, special rest homes where they followed a prescribed routine every day.
  • In the 1940s and 1950s, drugs were discovered to treat TB. After this, the death rate for TB in the United States dropped dramatically, and fewer and fewer people got TB.
  • In the mid-1980s, the number of TB cases started increasing again.
  • Since 1993, due to enhanced prevention and control efforts, the number of TB cases has been declining but continue to increase in poor and developing countries.

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Epidemiology

WHO declared tuberculosis (TB) a global emergency in 1993 in recognition of the growing importance of TB as a public health problem.

Some facts are as under

  1. Pulmonary TB is infectious and spreads through the air (droplets). If not treated, each person with active TB infects about 10 to 15 people every year.
  2. 1 in 10 person infected with TB bacilli will become sick with active TB in their lifetime; people with HIV are at a much greater risk.
  3. Tuberculosis is a disease of poverty affecting mostly young adults in their most productive years. The vast majority of TB deaths are in the developing world.
  4. 1.7 million People died from TB (including 380 000 women) in 2009.
  5. The TB death rate has fallen by 35% since 1990, and the number of deaths is declining.
  6. TB is among the three greatest causes of death among women aged 15-44.
  7. There were 9.4 million new TB cases (including 3.3 million women) in 2009, including 1.1 million cases among people with HIV.
  8. The estimated global incidence rate fell to 137 cases per 100 000 population in 2009, after peaking in 2004 at 142 cases per 100 000. The rate is still declining but too slowly.
  9. Globally, the percentage of people successfully treated reached the highest level at 86% in 2008.
  10. Since 1995, 41 million people have been successfully treated and up to 6 million lives saved through DOTS and the Stop TB Strategy. In 2009 5.8 million TB cases were notified through DOTS programs.
  11. Of the 22 TB high burden countries, 13 countries are on track to meet the 2015 Millennium Development Goal target and 12 countries are on track to reach the 2015 Stop TB Partnership targets.
  12. 1.6 million TB patients knew their HIV status in 2009 compared to 1.4 million in 2008 with the highest HIV testing rates of TB patients.
  13. 37% of HIV-positive TB patients were enrolled on antiretroviral and 75% started on cotrimoxazole preventive treatment in 2009.
  14. Multidrug-resistant TB (MDR-TB) is a form of TB that is difficult and expensive to treat and fails to respond to standard first-line drugs.
  15. There were an estimated 440 000 new MDR-TB cases in 2008, and 150 000 deaths from MDR-TB.
  16. It was estimated that in 2009, 3.3% of all new TB cases had MDR-TB.
  17. In 2010, the largest WHO MDR-TB survey reported the highest rates ever of MDR-TB, with peaks of up to 28% of new TB cases in some settings of the former Soviet Union.
  18. Many countries have developed plans to address MDR-TB, but the response globally is still insufficient. Extensively drug-resistant TB (XDR-TB) occurs when resistance to second-line drugs develops on top of MDR-TB.
  19. XDR-TB cases have been confirmed in 58 countries.

Pakistan Situation

  1. Pakistan is one of the 22 high tuberculosis burden countries in the world.   
  2. In 2009, the number of incident TB cases was estimated at 420 000 cases with an estimated incidence rate of 231/100 000 for all forms.
  3. The prevalence and mortality rates were estimated at 373 and 38 per 100 000 population, respectively.
  4. In terms of progress towards the 2015 targets, the 2009 prevalence and mortality rates constituted 66% and 46% of the baseline rates in 1990 (564 and 82 per 100 000 population, respectively).
  5. Tuberculosis (TB) is one of the major public health problems in Pakistan.
  6. Pakistan ranks 8th amongst the countries with the highest burden of TB in the world and contributes about 55% of tuberculosis burden in the Eastern Mediterranean Region (EMRO) of WHO.
  7. TB is responsible for 5.1 percent of the total national disease burden in Pakistan.
  8. The impact of TB on socio-economic status is substantial.
  9. The national average treatment success rate was 90% for the 2008 cohort, with low death, failure, default and transferred out rates (2%, 1%, 4% and 3%, respectively) . All provinces reported a treatment success rate higher than the target of 85% except Baluchistan where the treatment success rate was 82%, mainly due to a high defaulter rate of 10%.

 

Multidrug-resistant tuberculosis (MDR-TB)

  • Pakistan ranks 4th among the 27 high burden MDR-TB countries.
  • The estimated number of MDR-TB cases in 2009 accounted for 11 961, with a prevalence of 2.8% (<1-8%) among new cases, and 35% (<1-75%) among previously treated cases.

 

TB/HIV

  • Pakistan is in a state of concentrated HIV epidemic. In 2009, of the 267 451notified cases, only 4714(1.8%) of TB patients were tested for HIV, of them 7 were positive, reporting a prevalence of 0.2%.
  • During the same year, 2 917 PLHIV were screened for TB, of them 466 (16%) had active TB. HIV positive TB patients are provided with CPT and ART at the national AIDS control programme.

 

Year Event

  • 1947 Pakistan came into existence.
  • 1948 Mass vaccination with BCG.
  • 1959 First prevalence survey planned.
  • 1962 First prevalence survey conducted and report established
  • 1965 A 20 Year prospective plan for TB control is Launched.
  • 1966 A model Distt. TB centre is established.
  • 1971 1st meeting of National TB control board.
  • 1972 TB centre established in 16 Distt.
  • 1978 2nd TB prevalence survey.
  • 1985 UNCEF/WHO withdrew financial assistance to TB Control.
  • 1987 3rd TB prevalence survey.
  • 1993 WHO declared TB as a global emergency.
  • 1994 Federal and provincial TB board Reconstituted.
  • 1995 DOTS Strategy adopted national guide line issues, 5 pilot sites initiated.
  • 1996 National TB Directorate TB abolished.
  • 1997 Social action program SAPP – II initiated.
  • 1998 Decentralization of TB control programme implementation & integration of TB control with PHC.
  • 1999 TB included in priority list for public funding.
  • 1999 Federal and provincial PC- 1 prepared.
  • 2000 PC-1 approved and NTP established.
  • 2001 TB declares national emergency through Islamabad declaration on world TB day.
  • 2002 Drugs from GDF approved.
  • 2003 GFATM-2 grant secured from public private partnership. USAID grant received.
  • 2004 GFATM – 3& 4 approved.
  • 2004 89 Districts covered under DOTS, summary of TB control in Pakistan (1962 - 1992).
  • 2005 100% DOTS coverage in Public sector PHC.
  • PC- 1 approved. (Rs. 1.2 billion).


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National TB Control Program Pakistan

  • The National TB Control Program is responsible for overall TB control activities in the country i.e. policy guideline, technical support, coordination, monitoring and evaluation and research.
  • Provincial TB Control Programs are responsible for the actual care delivery process including program planning, training of care provides, case detection, case management, monitoring and supervision.
  • The overall objective of NTP is to reduce mortality, morbidity and disease transmission so that TB no longer a public health problem.

The National targets are in line with the Millennium Development Goals (MDGs) i.e.to cure 85% of detected new cases of sputum smear positive pulmonary TB and to detect 70% of estimated cases once 85% cure rate is achieved.

Presently, free diagnostic and treatment facilities for TB patients are available all over the country within the public sector health care delivery network. Currently, more than 1163 diagnostic facilities and more than 5000 treatment facilities are available throughout the country.

Public Private Mix (PPM)

A partnership between government and the private sector for the purpose of more effectively providing services and infra structure traditionally provided by the public sector.

It is widely recognized that a large proportion of TB patients seek care from private providers, mainly outside the network of National Tuberculosis Program (NTP).

These include private (for profit and not-for profit) providers and para- statal healthcare institutions and they do not follow the recommended DOTS strategy for management of TB, hence depriving patients of quality management and treatment.

Objectives

  • Increase detection of new sputum smear positive (NSS+) 70% cases, conversion rate 95% and cure at least 85% of the registered cases.
  • Increase awareness in the target community about TB.
  • To help implement, monitor, evaluate and scale up the public-private mix for effective tuberculosis control in the context of devolution in districts.

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Directly Observed Treatment Short Course (DOTS)

DOTS is the internationally recommended strategy for TB control.

It has five key components:

  • Sustained political commitment to increase human and financial resources and make TB control a nationwide priority integral to the national health system;
  • Access to quality-assured TB sputum microscopy for case detection among persons presenting with, or found through screening to have, symptoms of TB(most importantly, prolonged cough);
  • Standardized short-course chemotherapy for all cases of TB under proper case management conditions, including direct observation of treatment;
  • Uninterrupted supply of quality-assured drugs;
  • Rerecording and reporting system enabling outcome assessment of all patients and assessment of overall program performance.

 

When effectively applied

DOTS cures TB, with up to 95 percent cure rate, even in the poorest countries.

DOTS prevents new infections among children and adults and also prevent resistance to Anti-TB drugs.

According to World Bank report, DOTS is the most cost effective intervention amongst all health related interventions.

Government of Pakistan declared DOTS as National emergency in year 2001 and country achieved 100% population coverage (Public sector health facilities) in May 2005.

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Study Questions

Q-1     Define TUBERCULOSIS & name the causative organism?

Q-2     How old TUBERCULOSIS is? How it was discovered?

Q-3     What characteristic changes are seen in TB lung?   

Q-4     By whom & when TB bacteria was discovered?

Q-5     Which & when 1st Anti TB drug was discovered?

Q-6     Name the Anti TB drugs in currently in use?

Q-7     Why 1993 is important in history of TB?

Q-8     How many TB patients are present Worldwide & what is the rate of increase per year?

Q-9     What the prevalence & incidence is of drug sensitive & drug resistant TB in PAKISTAN?

Q-10     What are the five components of DOTs?

 

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Objectives

In this module we will learn about

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