By P.Madhuri,

Assistant Professor,Department of

Pharmacy Practice

Definition

• A chronic bacterial infection caused by Mycobacterium

tuberculosis, usually characterized pathologically by the

formation of granulomas. The most common site of infection

is the lung, but other organs may be involved.

• TB is a bacterial infection treatable by anti TB

drugs.

• TB in many countries is compounded who have co-infection

with the HIV .

Etiology

• TB is caused by tubercle bacilli which belong to genus

Mycobacterium.

• These form a large group but only three relatives are obligate

parasites that can cause TB disease.

• The UK data for 2008 show that M.tuberculosis was isolated

in 99% of confirmed cases.

• M.bovis in 0.4% and M. africanum in 0.5% that year.

• Mycobacterium species include :

• M. tuberculosis complex: M.tuberculosis, M. bovis.

• M. africanum

• Mycobacterium leprae: the cause of leprosy.

• Tuberculosis is caused by bacteria that spread from person to

person through microscopic droplets released into the air.

• This can happen when someone with the untreated, active

form of tuberculosis coughs, speaks, sneezes, spits, laughs or

sings.

• Although tuberculosis is contagious, it's not easy to catch

• You're much more likely to get tuberculosis from someone you

live with or work with than from a stranger.

• Most people with active TB who've had appropriate drug

treatment for at least two weeks are no longer contagious.• HIV

• Multi Drug-resistant TB: it is caused by the bacteria that are

resistant to at least isoniazid and rifampicin., the most effective

anti TB drugs.

• These results from either primary infection with resistant bacteria

or may develop in the course of patients treatment.

• XDR-TB is a form of Tb caused by bacteria that are resistant

to isoniazid and rifampicin as well as flouroquinolone and any

second line anti TB inject able drugs including amikacin,

kanomycin or kapreomycin.

Epidemiology

• In the United States, the incidence of TB began to decline

around 1900 because of improved living conditions.

• TB cases have increased since 1985, most likely due to the

increase in HIV.

• Tuberculosis continues to be a major health problem

worldwide. In 2008, the World Health Organization (WHO)

estimated that one-third of the global population was infected

with TB bacteria.

• With the spread of AIDS, tuberculosis continues to lay waste

to large populations.

• Mostly men are more likely to prone than women.

CLINICAL MANIFESTATIONS

• Coughing that lasts three or more weeks

• Haemoptysis

• Chest pain, or pain with breathing or coughing

• Unintentional weight loss

• Fatigue

• Fever

• Night sweats

• Chills

• Loss of appetite

• Sputum usually mucopurulant or purulent.

• Malaise.

• Predisposing factors:

• Close contact with large populations of people, i.e., schools,

nursing homes, dormitories, prisons, etc. 

•  Poor nutrition 

• Close with patients of TB especially those with sputum smear

positive pulmonary disease.

• HIV positive

• Alcoholism 

• Injecting drug users.

• Solid organ transplantation.

• Hematological malignancy for example leukemia.

• CRF or receiving hemodialysis.

TB TransmissionHow can you catch TB?

TB is spread through tiny drops

sprayed into the air when an infected

person coughs, sneezes, or speaks, or

another person breathes the air into

their lungs containing the TB bacteria.

TB TransmissionHow can you catch TB?

TB is not visible, and can only be seen under a

microscope.

TB droplets are more easily spread in areas

with poor air circulation.

TB Infection and Disease

The lungs are the most common

place for TB. This is known as

pulmonary TB.

TB of the voice box is the second

most common and is usually called

laryngeal TB.

TB Infection and Disease

TB can infect the brain, kidneys, bones, and other areas.

TB can also spread through the blood to other organs; this is

called miliary TB.

TB Infection & DiseaseThere are 2 Categories of TB: Latent & Active

TB infection of the lungs can fall into 2

categories of disease: Latent TB or Active

TB.

Latent TB means a person is infected by TB

bacteria, but cannot infect others, and is not

coughing or appearing sick.

Latent TB means the body’s immune system

has contained the infection.

TB - Infection & Disease Categories of TB - Latent

Persons with latent TB are

identified by a positive skin test

(PPD).

Persons who are not infected with

Mycobacterium tuberculosis have

a negative skin test (PPD).

TB - Infection & DiseaseCategories of TB - Latent

• When a person with a previously negative PPD, converts to a

positive PPD, the conversion indicates recent infection with

M. tuberculosis.

TB - Infection & DiseaseCategories of TB - Active

Active pulmonary and laryngeal TB means a person infected

with the TB bacteria is sick and can infect others unless they

are taking medicine prescribed by their physician to treat TB.

TB - Infection & DiseaseCategories of TB - Active

Persons with active TB disease

usually have some of the following

symptoms: cough ( 3 weeks or

more), feel weak, have a fever, lose

weight, experience night sweats,

cough up blood, or have chest pain

when coughing.

TB - Infection & Disease Categories of TB - Active

Persons with active TB need to take their

medications as prescribed in order to treat

the disease and prevent the spread to

others.

TB - Infection & DiseaseCategories of TB - Latent & Active

TB disease varies with age and the ability of your body

to fight off bacteria.

HIV is the strongest risk factor for the progression of

Latent TB to Active TB infection.

Tuberculosis Infection & Disease

Homeless persons are at increased risk for

catching TB.

TB cases are rising in the prison population

due to the increased number of HIV infected

inmates, crowded environment, and IV drug

abusers.

• Treatment

• First line therapy:

• The drugs isoniazid, ethambutanol, rifampicin, rifapentine and

pyrirazinamide usually of greatest effectiveness and lower

toxicity. They are most successful in most of the TB patients.

• At least 3-4 drug combinations are recommended.

1. Ethambutanol: it is a synthetic water based compound.

• MOA: this drug is a bacteriostatic.

• Spectrum of activity: it is active against many M.tuberculosis

• Strains as well as many other micro bacterial species.

• In many cases ethambutanol is given in combination with

rifampicin or isoniazid.

• Precautions and monitoring:

• It causes the adverse effects such as optic neuritis, drug fever,

abdominal pain, headache, dizziness and confusion

• Liver function tests, visual testing and renal function should

also be monitored.

• Dose: 15-25mg/kg/day, ROA: oral.

• Isoniazid :

• The mainstay of antitubercular therapy this drug should me

included in all therapeutic regimens.

• MOA: it is bacteriostatic for resting bacilli and bactericidal for

rapidly dividing organisms.

• Spectrum of activity: it has activity only against organisms in

genus mycobacterium like M. tuberculosis, M. bovis.

• Isoniazid is given in combination with other anti tubercular

drugs to prevent drug resistance in TB.

• Precautions and Monitoring:

• Most adverse effects of isoniazid is skin rash, fever, jaundice

and peripheral neuritis.

• Blood dyscrasias.

• Adverse GI effects include nausea, vomiting and epigastric

distress.

• Dose: 5-10 mg/kg

• ROA: oral, IV

• Rifampicin :

• It is a complex macrocylic agent.

• MOA: It is a bactericidal.

• Spectrum Of activity: it has an activity against most

mycobacterial strains.

• It has activity against other organisms like N. meningitis, S.

aureus. H. influenzae, C. trachomatis.

• Serious hepatic toxicity may result from rifampin therapy.liver

function tests should be done.

• Other adverse effects includes skin rash, drowsiness,

headache, fatigue, confusion, nausea, vomiting and abdominal

pain.

• Rifampin colors urine, sweat, tears, saliva and feces in orange

red colour.

• Dose:10mg/kg

• ROA: oral