Tuberculosis in the world.


Approximately one third of world population, including 11 million patients in the U.S., have a latent infection with Mycobacterium tuberculosis. In Italy the problem of immigration of people from weights where TB is endemic has created and will create notecoli problems of epidemic spread. Suffice to say that there exists the problem of the scourge of prostitution, the new slave trade of color and, therefore, no one is exempt from the risk of infection of tuberculosis. Again it should be noted that the drugs are less effective care.


In the U.S., most cases of tuberculosis on patients from countries where the disease is endemic. The infection is generally higher in economically disadvantaged populations and in immunosuppressed patients and in patients with AIDS. The problem is that the diagnosis should be promptly implemented, because delays in the identification and treatment of infection for easier transmission. There are new techniques for diagnosis representing the excess over the old test to the intradermal tuberculin which shows a state of allergy to products of the bacillus of Koch, and / or the detection of acid-alcohol resistant bacilli directly sull'escreato, what very complex, it is the technique based on the release of interferon gamma and amplification of nucleic acids allow more rapid identification and specific, respectively, of infection by M. tuberculosis and the presence of active disease.

In particular, with certainty, we can say that:

· The I'infezione screening for Mycobacterium tuberculosis should be performed in selected patients, especially if exposed to a high risk of infection or progression to active disease.

· The tests based on the release of interferon gamma-specific antigen are useful for screening of infection by M. tuberculosis, particularly in patients previously vaccinated with bacillus Calmette-Guerin or non-tuberculous mycobacterial infections

• The monotherapy with isoniazid is the treatment of choice for most patients with latent tuberculosis infection, and should be sufficient except in cases of patients with suspected primary drug-resistant tuberculosis, for which is shown to I'associazione more medications, and therapies conducted by direct observation.


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Epidemiology.



In 2007 the United States have been identified 13. 293 cases of active tuberculosis. Although the number of cases continues to decrease, the rate of decrease has submitted a slowdown. In the United States exposed to higher risk of infection are persons born in countries where I'infezione M. tuberculosis is endemic in these patients the infection rates are 10 times higher than those described in subjects born in the United States. Many of the ethnic and racial differences in the spread of cases of active tuberculosis can be attributed to differences in prevalence among persons born abroad or who have risk factors associated with low socioeconomic level. In 2007 I '11.3% of U.S. patients with active tuberculosis had a co-infection with virus deli iI' human immunodeficiency (human immunodeficiency virus, HIV). These data also represent the under-estimated because not cover the case of co-infection of California, in some cases of tuberculosis had also been sought as' possible co-infection with HIV. Delays in the identification or treatment of patients with active pulmonary tuberculosis or patients with a high risk of reactivation of latent tuberculosis infection facilitates the transmission of infection. For an effective infection control is essential to appropriate treatment of all patients with latent tuberculosis infection and active tuberculosis.



New diagnostic tests

Screening for causal research of M. tuberculosis is not a recommended procedure, is indicated instead a more targeted approach, involving the screening of subjects at high risk of latent tuberculosis infection or progression to active infection. Patients with latent infection and the risk of progression to active disease should be treated. The tuberculin skin test, also known as test or Mantoux test with purified protein derivative is available for a long time and has the advantage of a limited economic cost. Despite the problems such as low sensitivity, low specificity, the risk of inadequate follow-up of the patient to read the results, the tuberculin skin test is still considered the standard for the diagnosis of M. tuberculosis. False-positive test results may be caused by infections (with the non-tuberculosis mycobacteria, vaccination with bacillus Calmette-Guerin (BCG), (especially if recent), incorrect interpretations of test results (induration of care). The guidelines followed in the United States do not provide interpretation of test results, to consider I'eventuale BCG; new diagnostic tests are also unable to distinguish between a recent BCG vaccination and infection M. tuberculosis. The assay based on interferon gamma specific antigen identify the release of interferon gamma by T cell "memory" previously sensitized by in vitro stimulation with specific proteins of M. tuberculosis. These tests do not generate false-positive in patients previously vaccinated with BCG strains or affected by most non-tuberculous mycobacteria infection, thus allowing a more specific identification of M. tuberculosis. Like the tuberculin skin test, the assay based on the release of interferon spectrum simply identify M. tuberculosis, when used alone, therefore, these tests can not distinguish between active infection and hidden infections. With these tests, further HIV infections and conditions characterized by immunodeficiency, affecting the function T cells may be responsible for false-negative or inconclusive. Considered by itself, therefore, a negative tuberculin skin test or examination based on the release of interferon gamma is unable to exclude a diagnosis of tuberculosis.

E.. Who is at risk of tuberculosis?

· Subjects at risk of exposure and infection with Mycobacterium tuberculosis

· Subjects in close contact with patients with active tuberculosis confirmed

· Subjects from countries where TB is endemic, and who live in the U.S. for 5 years or less (especially children under 4 years)

· Resident and work in a boundary (eg prisons, care homes for chronic patients, homeless shelters)

· Operator contact with health patients at high risk

· Populations of low socio-economic level, who do not have adequate medical assistance

· Infants, children and adolescents exposed to adults at high risk populations

· Subjects with high risk of progression from latent tuberculosis infection to the infection active

· Patients infected with human immunodeficiency virus

· Patients recently (over the past 2 years) infected with M. tuberculosis

· Children younger than 4 years

· Patients immunosuppressed (eg patients with diabetes, chronic kidney disease or terminal, silicosis, cancers, malnutrition, patients undergoing prolonged therapy with corticosteroids, patients undergoing organ transplants, patients treated with inhibitors of tumor necrosis factor alpha)



The diagnosis of active tuberculosis is placed after a thorough medical history collection and a complete physical examination and tests as I'esecuzione with chest radiographs, sputum examinations cultivation or other tissues, and sometimes tissue biopsies . When suspected active tuberculosis. additional diagnostic evaluations should be conducted before the availability of the results of tuberculin skin test

or exam based on the release of interferon gamma. Several tests based on methods

amplification of nucleic acids allow us a quicker and more sensitive diagnosis of active tuberculosis and may be used as a complement to the smear for detecting acid-fast bacilli and the cultural examination for mycobacteria.



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T latent tuberculosis infection

Approximately one third of world population, including 11 million patients in the U.S., has a latent infection by M. tuberculosis. In most immunocompetent patients the risk of activation of latent infection during their lifetime is 5-10%. Amendments to "immunological fitness (eg HIV infections, diabetes, diseases with immunosuppression) may increase this risk. Patients with HIV infection have a significantly higher risk of activation

high. The higher risk of developing active tuberculosis as the first 2 years after infection. Patients at high risk of reactivation should be adequately informed of risks associated with reactivation, and are strongly recommended to undertake treatment of latent tuberculosis.

In most patients with latent tuberculosis infection treatment of choice involves the administration of isoniazid, an exception is made by patients with suspected resistance to the drug. Treatment options for latent tuberculosis treatment are listed in 9 months with isoniazid reduces the rate of reactivation during the dissolution of the granuloma, and is associated with higher rates of efficacy in patients with good compliance to treatment, approximately at 9 %

Nine months of isoniazid therapy are also indicated in patients with HIV infection and children under 4 years, the treatment reduces the risk of treatment failure and development of drug resistance. Advanced age per se no longer claim the exclusion from treatment. In patients who are unable or do not wish to undergo treatment for nine months can be considered the administration of isoniazid for six months and the treatment is shorter but less effective. In patients with poor compliance, and are not

able to take quick treatment with isoniazid rifampicin can reduce the rates of discontinuation of therapy, thereby improving I'efficacia. Patient compliance to treatment can be a significant problem, particularly in those who have not understood the benefits of treatment.



In patients who are unable to tolerate isoniazid or patients with known or suspected tuberculosis isoniazid or patients with known or suspected latent tuberculosis resistant to isoniazid an alternative treatment involves the administration of rifampicin for four months. Compared to the administration of isoniazid for 9 months, rifampin has un'epatotossicità child, and treatment completion rates higher. A significant problem, however, in the risk of drug interactions and development of resistance to rifampicin in patients with poor compliance. In patients with HIV infection, which have a higher risk of tuberculosis resistant to rifampicin, rifampin monotherapy is not recommended, there also a risk of interactions between rifampicin and other therapies involving associations between antiretroviral drugs.
 

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