Diagnosis

During the physical exam, your doctor will check your lymph nodes for swelling and use a stethoscope to listen carefully to the sounds your lungs make while you breathe.

The most commonly used diagnostic tool for tuberculosis is a simple skin test, though blood tests are becoming more commonplace. A small amount of a substance called PPD tuberculin is injected just below the skin of your inside forearm. You should feel only a slight needle prick.

Within 48 to 72 hours, a health care professional will check your arm for swelling at the injection site. A hard, raised red bump means you're likely to have TB infection. The size of the bump determines whether the test results are significant.

Results can be wrong

The TB skin test isn't perfect. Sometimes, it suggests that people have TB when they really don't. It can also indicate that people don't have TB when they really do.

A false-positive test may happen if you've been vaccinated recently with the bacillus Calmette-Guerin (BCG) vaccine. This tuberculosis vaccine is seldom used in the United States but is widely used in countries with high TB infection rates.

False-negative results may occur in certain populations — including children, older people and people with AIDS — who sometimes don't respond to the TB skin test. A false-negative result can also occur in people who've recently been infected with TB, but whose immune systems haven't yet reacted to the bacteria.

Blood tests

Blood tests may be used to confirm or rule out latent or active tuberculosis. These tests use sophisticated technology to measure your immune system's reaction to TB bacteria. QuantiFERON-TB Gold in-Tube test and T-Spot.TB test are two examples of TB blood tests.

These tests require only one office visit. A blood test may be useful if you're at high risk of TB infection but have a negative response to the skin test, or if you've recently received the BCG vaccine.

Imaging tests

If you've had a positive skin test, your doctor is likely to order a chest X-ray or a CT scan. This may show white spots in your lungs where your immune system has walled off TB bacteria, or it may reveal changes in your lungs caused by active tuberculosis. CT scans provide more-detailed images than do X-rays.

Sputum tests

If your chest X-ray shows signs of tuberculosis, your doctor may take samples of your sputum — the mucus that comes up when you cough. The samples are tested for TB bacteria.

Sputum samples can also be used to test for drug-resistant strains of TB. This helps your doctor choose the medications that are most likely to work. These tests can take four to eight weeks to be completed.

Treatment

Medications are the cornerstone of tuberculosis treatment. But treating TB takes much longer than treating other types of bacterial infections.

With tuberculosis, you must take antibiotics for at least six to nine months. The exact drugs and length of treatment depend on your age, overall health, possible drug resistance, the form of TB (latent or active) and the infection's location in the body.

Recent research suggests that a shorter term of treatment — four months instead of nine — with combined medication may be effective in keeping latent TB from becoming active TB. With the shorter course of treatment, people are more likely to take all their medication, and the risk of side effects is lessened. Studies are ongoing.

Most common TB drugs

If you have latent tuberculosis, you may need to take just one type of TB drug. Active tuberculosis, particularly if it's a drug-resistant strain, will require several drugs at once The most common medications used to treat tuberculosis include:

  • Isoniazid
  • Rifampin (Rifadin, Rimactane)
  • Ethambutol (Myambutol)
  • Pyrazinamide

If you have drug-resistant TB, a combination of antibiotics called fluoroquinolones and injectable medications, such as amikacin, kanamycin or capreomycin, are generally used for 20 to 30 months. Some types of TB are developing resistance to these medications as well.

A number of new drugs are being looked at as add-on therapy to the current drug-resistant combination treatment, including:

  • Bedaquiline
  • Linezolid

Medication side effects

Serious side effects of TB drugs aren't common but can be dangerous when they do occur. All tuberculosis medications can be highly toxic to your liver. When taking these medications, call your doctor immediately if you experience any of the following:

  • Nausea or vomiting
  • Loss of appetite
  • A yellow color to your skin (jaundice)
  • Dark urine
  • A fever that lasts three or more days and has no obvious cause

Completing treatment is essential

After a few weeks, you won't be contagious and you may start to feel better. It might be tempting to stop taking your TB drugs. But it is crucial that you finish the full course of therapy and take the medications exactly as prescribed by your doctor. Stopping treatment too soon or skipping doses can allow the bacteria that are still alive to become resistant to those drugs, leading to TB that is much more dangerous and difficult to treat.

To help people stick with their treatment, a program called directly observed therapy (DOT) is recommended. In this approach, a health care worker administers your medication so that you don't have to remember to take it on your own.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.

Coping and support

Treatment for tuberculosis is a complicated and lengthy process. But the only way to cure the disease is to stick with your treatment. You may find it helpful to have your medication given by a nurse or other health care professional so that you don't have to remember to take it on your own. In addition, try to maintain your normal activities and hobbies and stay connected with family and friends.

Keep in mind that your physical health can affect your mental health. Denial, anger and frustration are normal when you must deal with something difficult and unexpected. At times, you may need more tools to deal with these or other emotions. Professionals, such as therapists or behavioral psychologists, can help you develop positive coping strategies.

Preparing for your appointment

If you suspect that you have tuberculosis, contact your primary care doctor. You may be referred to a doctor who specializes in infectious diseases or lung diseases (pulmonologist).

What you can do

  • Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance.
  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including any recent life changes or international travel.
  • Make a list of all medications, vitamins or supplements that you're taking.
  • Write down questions to ask your doctor.

Preparing a list of questions can help you make the most of your time with your doctor. For tuberculosis, some basic questions to ask your doctor include:

  • What's the most likely cause of my symptoms?
  • Do I need any tests?
  • What treatments are available? Which do you recommend?
  • What if the treatment doesn't work?
  • How long do I have to stay on the treatment?
  • How often do I need to follow up with you?
  • I have other health problems. How can I best manage these conditions together?

What to expect from your doctor

Your doctor may ask some of the following questions:

  • What are your symptoms, and when did they start?
  • Does anyone you know have active tuberculosis?
  • Do you have HIV or AIDS?
  • Were you born in another country, or have you traveled in another country?
  • Have you ever lived with someone who had tuberculosis?
  • Were you vaccinated against tuberculosis as an infant?
  • Have you ever had tuberculosis or a positive skin test?
  • Have you ever taken medicine for TB? If so, what kind and for how long?
  • What kind of work do you do?
  • Do you use alcohol or recreational drugs?
Aug. 08, 2017
References
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