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HIV, AIDS, and Tuberculosis


Diagnosing Tuberculosis With HIV

As soon as you know you have HIV, get a tuberculin skin test (TST). The test involves injecting a small amount of fluid with a TB protein under the skin on your arm. After two or three days, a health care provider checks for swelling at the site of the injection, which is a sign of tuberculosis infection. An alternative is to have one of two approved blood tests collectively called interferon-gamma release assays or IGRAs.

It can be difficult to diagnose tuberculosis for these reasons:

  • If you've recently been infected with tuberculosis or if your immune system is very damaged, you may not test positive but still be infected.
  • You may test positive, but have a related bacterial infection, not tuberculosis. You may need to have other tests to confirm whether you have active TB.

Other TB tests you may need include:

  • A chest X-ray, which produces a picture of your lungs.
  • A TB smear test, where your doctor takes a sample of phlegm and examines it under a microscope for signs of bacteria.
  • A sputum culture, which involves growing the bacteria to reveal signs of active tuberculosis.

If you test negative, you should be retested once a year. If you had a baby after you became HIV-positive, have your baby tested at 9 to 12 months of age.

Treating Tuberculosis if You Have HIV

If you are infected with tuberculosis, get treated right away, whether or not you have active disease. Complete each of your treatments, exactly as your doctor tells you. Otherwise, the tuberculosis germs can become resistant and the drugs may stop working.

To treat active tuberculosis, you will take more than one drug for several months. This is a common combination of drugs:

  • Myambutol (ethambutol)
  • Nydrazid (isoniazid)
  • Tebrazid (pyrazinamide)
  • Rifadin or Rimactane (rifampin)
  • Nydrazid (isoniazid) (INH)
  • Pyridoxine (vitamin B6)

Here's what to expect during and after TB treatment:

  • Drugs for HIV and drugs for TB can interact with each other. Your doctor will decide which combination of medications works best for you. As long as your CD4 cell count isn't too low, your doctor may recommend treating the tuberculosis before putting you on antiretroviral therapy.
  • You will likely need to stay away from others for a few weeks so you won't spread the disease. After about three weeks of treatment, you won't be able to pass on the disease anymore. A health care provider can confirm this with three negative TB smear tests.
  • To be totally cured, keep taking your medications as your doctor tells you to. This will prevent you from becoming sick with tuberculosis again.


Preventing Tuberculosis

Drugs to prevent latent tuberculosis from becoming active are called prophylaxis. Before starting this preventive therapy, your doctor will first need to confirm that active disease is not present.

These are common medications used for prophylaxis:

  • Nydrazid (isoniazid) (INH) for 6-12 months.
  • Pyridoxine (vitamin B6) to prevent peripheral neuropathy, a side effect of INH.
  • Rifadin or Rimactane (rifampin), if isoniazid is not effective.

WebMD Medical Reference

Reviewed by David T. Derrer, MD on August 17, 2014
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