Associated Conditions of Tuberculosis
|About associated conditions: Associated conditions are those which appear statistically related, but do not have a clear cause or effect relationship. Whereas the complications are caused by Tuberculosis, and underlying causes may be causes of Tuberculosis, the following list shows associated conditions that simply appear with higher frequency in people who have Tuberculosis. In some cases, there may be overlap between this list and risk factors for Tuberculosis. People with Tuberculosis may be more likely to get a condition on the list of associated conditions, or the reverse may be true, or both. Whether they are causes of, caused by, or simply coincidentally related to Tuberculosis is not always clear. For general information, see Associated Condition Misdiagnosis.|
Associated conditions list: The list of conditions mentioned by various sources as associated with Tuberculosis includes:
Tuberculosis as a risk factor: Another type of associated condition is one for which Tuberculosis is itself a risk factor. The conditions for which Tuberculosis is listed as a risk factor includes:
Associated conditions: WHO estimates that 4.4 million people worldwide are coinfected with TB and HIV. By the year 2000, TB will claim 1 million lives annually among the HIV-infected, WHO projects, making TB the leading cause of death in HIV-infected individuals. In the United States, an estimated 100,000 HIV-infected people also carry M. tuberculosis, according to CDC.
TB frequently occurs early in the course of HIV infection, often months to years before other opportunistic infections such as Pneumocystis carinii pneumonia. TB may be the first indication that a person is HIV-infected, and often occurs in areas outside the lungs, particularly in the later stages of HIV disease.
In the United States, people coinfected with TB and HIV develop active TB at a rate of about 8 percent each year. By comparison, otherwise healthy individuals infected with M. tuberculosis have a 10 percent lifetime risk of developing active TB. People with HIV also are at greater risk of having a new infection progress directly to active disease.
MDR-TB in people coinfected with HIV appears to have a more rapid and deadly disease course than seen in patients with MDR-TB who are otherwise healthy.
Diagnosing TB in HIV-infected people is often difficult. These patients frequently have conditions that produce symptoms similar to those of TB, and may not react to the standard tuberculin skin test because their immune systems are suppressed. Although investigators have hypothesized that a two-stage TB skin test might be more reliable than a single-stage test in HIV-infected individuals, a recently completed NIAID study found this not to be the case.
X-rays, sputum smears, and physical exams may also fail to
provide an indication of TB infection in HIV-infected individuals.
As a consequence, doctors must often decide to begin anti-TB
therapy in HIV-infected people suspected of having active TB while
waiting for the results of cultures of sputum or other specimens.1
1. excerpt from Tuberculosis, NIAID Fact Sheet: NIAID
Last revision: June 23, 2003
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