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2011-04-01 11:37:29

Information about tuberculosis
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  1. Tuberculosis
    A reportable chronic infectious disease transmitted by mycobacterium tuberculosis that most commonly affects the lungs

    Can also occur in kidneys, bones, lymph nodes, meninges, and disseminated throughout the body

    Causes more deaths worldwide than any other infectious disease

    Estimated that between 19 and 43% of the worlds population is infected
  2. Incidence
    Majority have healed or dormant TB

    Less than 5% of persons exposed or infected will ever develop clinical disease

    TB treated on an outpatient basis

    Deaths from TB continue to occur: approx. 2,000 per year in the United States
  3. Risk Factors
    TB can affect anyone, but certain groups are high risk.


    Racial and ethnic groups: Native Americans, Eskimos, African Americans, immigrants from Southeast Asia, Ethiopia, Latin America, Haiti, economically disadvantaged or homeless

    ETOH abusers

    Chemically dependent

    Infants and children < 5 years

    Immunosuppressed: HIV infection, cancer/chemotherapy, malnutrition, or on corticosteroids

    Residents of inner-city neighborhoods

    MDR strains have increased in the US from 2% à 9%
  4. Etiology
    Aerobic organism is an acid-fast bacillus gram (+)

    Transmitted by droplet nuclei emitted during coughing, sneezing, speaking, laughing, or singing

    Brief exposure usually does not cause infection

    More commonly spread to individuals with repeated close contact with the infected person

    Disease is not spread by hands, dishes, books, etc.
  5. Pathophysiology
    First time a client is infected with TB, it is said to be a primary infection.

    Infection confirmed by a positive mantoux test

    Only about 5% develop active clinical disease.

    Primary TB infections are usually located in the apices of the lungs or near the pleura of the lower lobes.

    Organism requires O2 to grow.

    The primary infection may undergo a process of necrotic degeneration (caseation) which produces cavities filled with a cheese-like mass of tubercle bacilli, dead white blood cells, and necrotic lung tissue (primary tubercle).

    Most primary tubercles heal over a period of 3 months into calcified lesions (Ghon tubercle).

    These lesions may contain living bacilli that can reactivate and can cause reinfection or secondary TB.
  6. Positive Mantoux Test
    Persons who become sensitized to the tubercle bacillus develop an antigen-antibody reaction.

    Occurs 3-10 weeks after implantation of original TB.

    Sensitization remains throughout life, unless something interferes with the immune response
  7. First line of drugs:




  8. Diagnostic Tests
    Tuberculin skin testing

    A reaction is considered significant when it is 10mm or more in diameter.

    The test cannot determine whether or not an infection is active disease.

    5-9mm is a doubtful reaction, except for persons with HIV. The test is usually repeated within a week.

    • 0-4mm- little or no sensitivity, however if patient’s history indicates exposure, the test should be repeated.
    • Skin testing can produce false positive and false negative results in 20% of patients.

    Positive reaction occurs 2-3 months after initial infection.


    Bacteriological studies

    Cultures and smears
  9. Medical Management
    Treatment of TB rarely requires in-hospital care.

    The mainstay of TB treatment is pharmacological.

    Drug therapy is used to treat individuals with disease as well as prevent disease in infected persons.

    Drugs are usually administered as a single dose before breakfast to ensure adequate absorption.

    For active disease, treatment consists of at least 4 drugs to start

    5 primary drugs are: INH, Rifampin, PZA, Ethambutol, Streptomycin

    In most areas of the United States, drug therapy is free of charge.

    • Greater than 90% of clients convert to negative sputum status within 3 months. Take with food No alcohol
    • INH is bacteriosideal, it can cause peripheral neurides: numbness and tingling (People are on B6 vitamins also)

    Rfampin is bacteriosidal broad spectrum (urine and tear turn orange) it decreases effectiveness of oral contraceptive and anticoagulants. (These are the drugs pt stay on INH AND RFAMPIN they cause liver problems)

    • PZA cause jaundice,
    • Ethambutol: need vision test ( only on it for a couple of month)

    • Streptomycin: causes audio toxity
    • Important to follow up to ensure adherence to treatment regimen.

    The major side-effect of INH, Rifampin, and PZA is hepatitis