Tuberculosis
  International awareness day March 24



Overview
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Causes
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    The bacterium that causes tuberculosis spreads in microscopic droplets that are released into the air when someone with the untreated, active form of the disease coughs, speaks, laughs, sings or sneezes.
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    Source: Tuberculosis: Causes - MayoClinic.com (mayoclinic.com)

Epidemiology
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    It is estimated that 2 million people die from TB each year and more than 8 million people develop active TB each year. TB strikes people most often during their most productive years. The disease has reached alarming proportions in Africa, Asia and Latin America. In the last decade, TB cases have increased by about 20%. If this trend continues, there will be a total of 36 million deaths from TB by the year 2020.
    Source: Lung diseases - Tuberculosis - TB in Canada & the world : Canadian Lung Association (lung.ca)

Prevention
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    In general, TB is a preventable disease. From a public health standpoint, the best way to control TB is to diagnose and treat people with TB infection before they develop active disease and to take careful precautions with people hospitalized with TB. But there are also measures you can take on your own to help protect yourself and others.
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    Source: Tuberculosis: Prevention - MayoClinic.com (mayoclinic.com)

Symptoms
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    Tuberculosis is either latent (dormant) or active.

    * Latent TB means that you have the TB-causing bacteria in your body, but you cannot spread the disease to others. However, you can still develop active TB.
    * Active TB means the infection is spreading in your body and, if your lungs are infected, you can spread the disease to others.

    Symptoms of active TB may include:

    * Ongoing cough that brings up thick, cloudy, and sometimes bloody mucus from the lungs (sputum).
    * Fatigue and weight loss.
    * Night sweats and fever.
    * Rapid heartbeat.
    * Swelling in the neck (when lymph nodes in the neck are infected).
    * Shortness of breath and chest pain (in rare cases).

    Sometimes, when you are first infected, the disease is so mild you don't know you have it. This is also true for people with latent TB because they have no symptoms.
    Source: Tuberculosis (TB)-Topic Overview (webmd.com)

Diagnosis
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    The doctor will complete the following tests to diagnose tuberculosis:

    * Chest x-ray: The most common diagnostic test that leads to the suspicion of infection is a chest x-ray.
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    * Mantoux skin test:This test helps identify people infected with M tuberculosis but who have no symptoms. A doctor must read the test.
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    * Sputum testing: Sputum testing for acid-fast bacilli is the only test that confirms a TB diagnosis. If sputum (the mucus you cough up) is available, or can be induced, a lab test may give a positive result in up to 30% of people with active disease.
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    Source: Tuberculosis Causes, Symptoms, Treatment, and Prevention on eMedicineHealth.com (emedicinehealth.com)

Treatment
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    The most common drugs used to fight TB are the following:

    * Isoniazid (INH)
    * Pyrazinamide (PZA)
    * Rifampin
    * Ethambutol

    Your doctor will determine the best antibiotics for you. Antibiotics must be taken for at least 6 months to kill all the TB bacteria. Taking more than one antibiotic at a time prevents drug-resistant TB .
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    Source: Treatment of TB Disease - Tuberculosis Fact Sheet - Tuberculosis Prevention and Control - Public Health Agency of Canada (phac-aspc.gc.ca)

Illustrations
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Source: Tuberculosis Causes, Symptoms, Treatment, and Prevention on eMedicineHealth.com (images.emedicinehealth.com)


Mycobacteria
Kinyoun stain shows presence of mycobacteria in sputum sample

Source: MedlinePlus Medical Encyclopedia: Positive ppd skin test (nlm.nih.gov)


Mantoux Skin Test
The positive immunologic response to PPD antigen is seen here. The size of the papule is over 2 cm in diameter.

News
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Scientific Articles (a selection for patients)
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    Immunization by a bacterial aerosol
    Garcia-Contreras L, Wong YL, Muttil P, Padilla D, Sadoff J, Derousse J, Germishuizen WA, Goonesekera S, Elbert K, Bloom BR, Miller R, Fourie PB, Hickey A, Edwards D.
    University of North Carolina, Chapel Hill, NC 27599-7360

    (Details: open / close)
    Source: Immunization by a bacterial aerosol. [Proc Natl Acad Sci U S A. 2008] - PubMed Result (ncbi.nlm.nih.gov)
    Treatment of latent tuberculosis infection in HIV infected persons
    Woldehanna S, Volmink J.

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    Source: Treatment of latent tuberculosis infection in HIV infected persons (cochrane.org)

Medical Journals (for health professionals)
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