A brief discussion on tuberculosis

2. 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 .

3. 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 :

4. • 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

5. • 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.

6. • 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.

7. • 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.

8. 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

9. • 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

10. • Alcoholism
• Injecting drug users.
• Solid organ transplantation.
• Hematological malignancy for example leukemia.
• CRF or receiving hemodialysis.

11. TB Transmission
How 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.

12. TB Transmission
How 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.

13. 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.

14. 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.

15. TB Infection & Disease
There 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.

16. 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).

17. TB - Infection & Disease
Categories of TB - Latent
• When a person with a previously negative PPD, converts to a
positive PPD, the conversion indicates recent infection with
M. tuberculosis.

18. TB - Infection & Disease
Categories 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.

19. TB - Infection & Disease
Categories 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.

20. 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.

21. TB - Infection & Disease
Categories 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.

22. 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.

34. • 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

35. • 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.

36. • 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.

37. • 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

38. • 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.

39. • 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