TUBERCULOSIS

By

Sriloy Mohanty

B.N.Y.S,2nd year

S-VYASA

Contents…• Introduction• Problem statement• Epidemological indices• Natural history of TB• Definition of TB cases and

treatment• Natural history of TB• Modes Of Transmission• Control of TB• Chemotherapy

• Childhood TB• BCG vaccination• Chemoprophylaxis• NTP• Stop TB strategy• TB and HIV• Epidemiological impact

INTRODUCTION Specific infectious diseases

Caused by-M. tuberculosis

Primary effect on lungs-pulmonary tuberculosis

Also affects intestine,meninges,bones, joints,lymph nodes,etc.

Cont… It affects also animals like cattles

Known as “Bovine tuberculosis”

May communicated to man

Problem statement Distribution-worldwide WHO estimates that about 9.2 million new cases

of TB occurred in 2006 Of these cases, 4.1 million were new smear

positive cases This includes 789,000 tuberculosis with HIV co-

infected cases There were 14.4 million prevalent cases An estimated 1.7 million people died from TB

which 231,000 were those co-infected with HIV

31.8 million new and relapse cases and 15.5 million smear positive case were notified by DOTS Programme between 1995-2006

India India is the first rank in incidence 1/5th of global burden of TB 1.8 million persons develop TB of which

0.8 million are new smear positive (highly infectious)

0.37 million people die every year DOTS program was launched in March

1997

TB estimates for IndiaPopulation 1151 million

Global rank (by estimated number of cases) 1

Incidence (all cases/1 lakh population/year) 168

Incidence (new smear +ve cases/lakh population/year) 75

Prevalence (smear +ve cases/lakh population) 299

TB mortality/1 lakh population/year 28

% of new TB cases HIV positive 1.2

% of new case multidrug resistance 2.8

Previously treated TB cases multidrug resistance (%) 17

It is mainly a disease of the poor

Majority of victims are migrant laborers, slum dwellers, residents of backward areas and tribal pockets

Epidemological indices

Prevalence of infection Percentage of individual who are positive to

tuberculin test Incidence of new cases

Percentage of new cases/1000people/1year Prevalance of suspect cases

Based on X-ray examination of chast

Mortality rate Number of death from TB

Prevalance of drugs Prevalance of patient excreting tubercle

bacilli resistant to anti-tubercle drugs

Definition of TB cases and

treatment Case of TB

patient in whom TB is confirmed by tests Sputum smear examination

Test for screening of TB (acid fast bacilli are stain red by ziehl neelsen method)

New case Person with smear positive test having pulmonary

TB who had never taken any treatment

Relapse Person who returns smear +ve having previously

been treated and declared cured Failure case

Person with smear +ve treated and again become +ve at 5th month or later during treatment

Return after default Person,returns to sputum positive ,after having left

treatment for atleast two months Transfer in

A patient recorded in another administrative area register and transferred into another area to continue treatment

Transfer out A patient who has been transferred to another

area register and treatment results are not known

Cured Negative smear after treatment

Treatment completed Initially smear –ve or +ve and after receiving

full course of treatment becomes –ve Adherence

Person takes appropriate drugs regimen for required time

Natural history of TB

Agent factor M.tuberculosis is a intracellular parasite

Ingested by phagocytes but resistant to intracellular killing

Indian tubercle bacillus is said to be less virulent then the europian bacillus

Cont… Number of “atypical” myobacteria have been

isolated from man

They are of 4 types Photochromogens Scotochromogens Non-photochromogens Rapid growers

Source of infection Two source of infection

Human source-person whose sputum is positive for tubercle bacilli Discharge of bacilli in their sputum

Bovine source-infection is usually by milk Not a problem in India because of the practice of

boiling milk before consuption

Communicability Patient are infective as long as they remain

untreated

Infection can be reduced by 90% within 48 hours by using anti-microbial treatment

Host Factor

AGE Affects all ages In India under 5 age group-1% At the age of 15years-30%

SEX More prevalent in male then female

HEREDITY It is not a hereditary disease

NUTRITION Malnutrition is believed to predispose to TB Diet had no effect on the recovery of patient

IMMUNITY No inherited immunity against TB Acquired after natural infection or BCG

vaccination

Social factor TB is a disease with both social and

medical aspects Social factors includes

Poor quality of life Poor housing Population explosion Early marriages Lack of awareness of causes of disease

TUBERCULIN TEST

Discovered by Von Pirquet(1907) Three main test are currently in use

Mantoux intradermal test Heaf test Tine multiple puncture test

Modes Of Transmission

Mainly by droplate infection and droplate nuclei generated by sputum positive patient

Particle should be fresh enough to carry

Coughing generates all size of droplates

Notes-not transmitted by fomites

Incubation period

Ranges from 3-6 week

Control of TB

Reduction in prevalence and incidence WHO defines control as prevalance of natural

infection in the age 0-14yrs is of the order of 1% In india it is about 40% Control measure consists of

Curative component-case finding and treatment Preventive component-BCG vaccination

Case finding THE CASE

Detection of sputum positive case Case is defined by WHO as patient with

sputum positive for tubercle bacilli Target group

Pulmonary TB has one or more of the symptoms like Cough and Fever Chest problems

Case finding tools Sputum examination

Sputum smear examination Who also have problems like

persistant cough of about 3-4weeks Continous fever Chest pain haemoptysis

Chemotherapy Indicated for every case of active BT Objectives are

Elimination of both the fast and slow multiplying bacilli

Mainly elimination of bacilli from patients sputum Available for free of charge

Anti-tuberculosis drugs

An anti-tuberculosis drug should follow some criteria's like

Free from side effects Highly effective Easy to administrate Reasonably cheap

Classification of drugs

Currently used drugs are classified in to

Bactericidal drugs-kills the bacteria

Bacteriostatic drugs-inhibits the multiplication of the bacilli and leads to destruction by the immune mechanism of the host

Bactericidal drugs Rifampicin(RMP)

Powerful Bactericidal drugs Permeates all tissue membrane Only Bactericidal drugs active against the dormant

bacilli Only oral drug 10-12mg/kg body weight May feel nausea,gastritis,purpra

INH Most powerful drug Can penitrate the cell membrane Active against intracellular and extracellular bacilli It can also pass BBB,present in CSF 4-5gm/kg body weight

Streptomycin Act on rapidly multiplying bacilli Less active on slow multiplying bacilli No action on persisters Non-permeate cell wall 0.75-1gm in a single injection

Pyrazinamide Active against slow-multiplying intracellular

bacilli Drug given orally Usual dose 30gm/kg body weight Recommended in tuberculous meningitis

Bacteriostatic drugs

Ethambutol Used in combination to prevent the

emergence to the drugs Given orally Side-effect-retro-bulbar neuritis 15mg/kg body weight given in 2-3 doses

Thioacetazone Companion drug to INH Adult dose-2mg/kg body weight Side-effect includes gastrointestinal

disturbances, blurring of vision, haemolytic anaemia

Two-phase chemotherapy

Consist of two phase of effective treatment Short aggressive or intense phase

Lasting 1-3months Three or more drugs are combined to kill initialy

Continuation phase Aimed to sterilizing the smaller number of

dormant Not less then 18 months If rifampcin and pyrazinamide applied,then it can

reduced to 6-9 months

Treatment during pregnancy

Streptomycin can cause permanent deafness in the baby

So ethambutol should be used instead of streptomycin,

Isoniazid, rifampicin, pyrazinamide and ethambutol are safe to use

Second line drugs should not be used becouse these are teratogenic (flouroquinolomes,ethionamide)

Childhood TB TB in children present between 10-20% of all BT Sourse is usually adult Frequency of childhood TB depends

Number of infectious case Closeness of contact with an infectious case Age of the child when exposed to TB

Childhood TB is mainly due to failure in control of TB in adult

Under 5 age group-20% The commonest age-1-4years

BCG vaccination Calmette and guerin in 1919 discovered bacille

Calmette guerin(BCG) Avirulent for man while retaining its capacity to

induce an immune response During 1921-1925-given orally After 1927-intradermal technique 1948-it is accepted by TB workers

AIM Induce benign artificial primary infection

By stimulating an acquired resistance

Vaccine Widely used live bacterial vaccination Derived from an attenuated bovine stain of

tubercle bacilli WHO has recommended the “Danish 1331” stain

for production of BCG vaccination

Types of vaccination

Two types of BCG vaccination Liquid vaccination(fresh) Freeze-dried vaccination(stable)

BCG is stable for several weeks in a tropical climate and for up to 1 year if kept away from direct light and stored in cool environment preferably refrigerator at a temperature below 10 deg C

Normal saline is recommended for diluent for reconstituting the vaccine

Dosage For vaccination the usual strength is 0.1 g in 0.1

ml volume

For new born (below 4 weeks) 0.5 ml, because the skin of the new born is thin

Administration Inject the vaccine intradermally using a

tuberculin syringe (recommended by WHO) If injected subcutaneously an abscess is likely to

develop The site of injection should be above the insertion

of deltoid

Phenomena after vaccination

After 2-3 weeks a papule develops at the site of vaccination

It increases slowly in the diameter about 4-8 mm in 5 weeks

Healing occurs within 6-12weeks Round scar is formed

complication Prolonged severe ulceration Supractive lymphadenitis Osteomyelitis Death

Protective value Protection from 15-20years

RevaccinationEven 80 years after the development of the vaccine, it is not known whether booster doses are indicated or advisable

ContraindicationGeneralized eczema, infective dermatosis, hypogammaglobulinaemia, to those with a history of deficient immunity

Patient under immunosuppresent treatment and in pregnancy

Direct BCG vaccination Vaccination without a prior tuberculin test has been

adopted as a National policy in many developing countries including India

No adverse effects have been reported even if BCG is given to tuberculin – positive reactors

Impact BCG is less effective than the chemotherapy

BCG vaccination and HIV infection A single dose of BCG vaccine should be given to

all healthy infants as soon as possible after birth unless the child presented with symptomatic HIV infection

Combined vaccination BCG may be given at the same time as OPV. DPT

vaccine may also be given at the same time as BCG, but in different arm without reducing the immune responses or increasing the rate of complication

Chemoprophylaxis The case against INH chemoprophylaxis rests on

3 points: It is a costly exercise It is not strikingly effective It can induce hepatitis

According to WHO mass treatment is not feasible In this context, BCG gets priority over

chemoprophylaxis

Surveillance An integral part of any effective TB Concern with two distinct aspect

Surveillance of TB situation Surveillance of control measures(BCG and chemotherapy)

Role of hospital Inspite of effective domicilliary treatment service

there will be need for hospitalization for some person Indications are

Emergencies Surgical treatment Management of serious type of TB(meningeal TB) Social indication

Drugs resistance All drugs used in TB produce resistance Resistance may be of two types

Pretreatment resistance Acquired resistance

National Tuberculosis Programme (NTP)

NTP has been under operation since 1962

The long term goal of NTP is “to reduce the problem of tuberculosis in the community sufficiently quickly to the level where it ceases to be a public health problem”.

Revised NTP The Govt. of India, WHO and World Bank

together reviewed the NTP in the year 1992

The main pillars of the revised strategy are; Achievement of not less than 85% cure rate amongst

infectious cases of TB, through short course chemotherapy involving peripheral health functionary

Detecting 70% of the estimated cases – through quality sputum microscopy

Involvement of NGOs Direct Observed Therapy Short – term (DOTS) – a

community based TB treatment and care strategy

Stop TB strategy 2006- WHO launched Core of the strategy – DOTS Indicators used to measure implementation and

impact of TB control: Case detection Treatment success Incidence Prevalence Deaths

Stop TB partnership target

By 2005 70% of people with sputum smear positive TB will

be diagnosed By 2015

Global burden of TB will be reduced by 50% relative to 1990 levels

By 2050 Global incidence of TB will be less then or equal to 1

case/million population/year

TB and HIV HIV virus damages the bodies natural defense Accelerates the speed at which TB progresses

from a harmful infection to life – threatening condition

Epidemiological impact

Reactivation of latent infection People who are infected with both TB and HIV are

25-30 times more likely to develop TB than the people infected with only TB

Recurring infection People having HIV who have been cured of TB may

be at more risk of developing TB again In the community

Educate people that TB is curable and the people are no longer infectious after the first few weeks of treatment

Thank You…