Tuberculosis (TB)

| What is tuberculosis? | Is tuberculosis an infectious and contagious disease that can be treated? | How does a person get TB? | What happens to the body when a person gets TB? | How common is TB and who gets it? | How can I get tested for TB? | How do patients with tuberculosis feel? | How does a doctor diagnose tuberculosis? | How is tuberculosis treated? | What are the side effects of medicines for TB? | Why do I need to take TB medicine regularly? | How can I keep from spreading TB?
 | What is drug-resistant tuberculosis? Can people with drug-resistant tuberculosis be treated? | Can people be vaccinated against tuberculosis? | What is the difference between tuberculosis disease and latent tuberculosis infection? | If I have latent TB infection, how can I keep from developing active TB disease? | What if I have HIV infection? | What's in the future for TB? | What is directly observed therapy? | Tuberculosis At A Glance |

How does a doctor diagnose tuberculosis?

TB can be diagnosed in several different ways, including chest X-rays, analysis of sputum, and skin tests. Sometimes, the chest x-rays can reveal evidence of active tuberculosis pneumonia.

Other times, the x-rays may show scarring (fibrosis) or hardening (calcification) in the lungs, suggesting that the TB is contained and inactive. Examination of the sputum on a slide (smear) under the microscope can show the presence of the tuberculosis bacteria. A sample of the sputum can also be grown (cultured) in special incubators so that the tuberculosis bacteria can subsequently be identified.

Several types of skin tests are used to screen for TB. These so-called tuberculin skin tests include the Mantoux test, the Tine test, and the PPD.

In each of these tests, a small amount of dead tuberculosis bacteria is injected under the skin. If a person is not infected with TB, then no reaction will occur at the site of the injection (a negative skin test). If a person is infected with tuberculosis, however, a raised and reddened area will occur around the site of the test injection. This reaction, a positive skin test, occurs in about 48 to 72 hours after the injection.

If the infection with tuberculosis has occurred recently, however, the skin test can be falsely negative. The reason for a false negative test with a recent infection is that it usually takes two to ten weeks after the time of infection with tuberculosis before the skin test becomes positive. The skin test can also be falsely negative if a person's immune system is weakened or deficient due to another illness such as AIDS or cancer, or while taking medications that can suppress the immune response, such as cortisone or anti-cancer drugs.

Remember, however, that the TB skin test cannot determine whether the disease is active or not. This determination requires the chest x-rays and/or sputum analysis (smear and culture) in the laboratory. A special test to diagnose TB, called the PCR (polymerase chain reaction) for TB, is now available. This test is extremely sensitive (detects minute amounts of the bacteria) and specific (detects only the TB bacteria) but, of course, it also is very expensive.

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How is tuberculosis treated?

A person with a positive skin test, a normal chest x-ray, and no symptoms most likely has only a few TB germs in an inactive state and is not contagious. Nevertheless, treatment with an antibiotic may be recommended for this person to prevent the TB from turning into an active infection.

The antibiotic used for this purpose is called isoniazid (INH). If taken for 6 to 12 months, it will prevent the TB from becoming active in the future. In fact, if a person with a positive skin test does not take INH, there is a 5 to 10% lifelong risk that the TB will become active.

Taking isoniazid can be inadvisable (contraindicated) with pregnancy, alcoholism, and liver disease. Also, isoniazid can have side effects. The side effects occur infrequently, but a rash can develop and the patient can feel tired or irritable.

Liver damage from isoniazid is a rare occurrence and typically reverses once the drug is stopped.

Very rarely, however, especially in older people, the liver damage (INH hepatitis) can even be fatal. It is important, therefore, for the doctor to monitor a patient's liver by periodically ordering blood tests called "liver function tests" during the course of INH therapy.

A person with a positive skin test along with an abnormal chest x-ray and sputum evidencing TB bacteria has active TB and is contagious.

As already mentioned, active TB usually is accompanied by symptoms, such as a cough, fever, weight loss, and fatigue.

If you have active TB disease, you will need to take several different medicines. This is because there are many bacteria to be killed. Taking several medicines will do a better job of killing all of the bacteria and preventing them from becoming resistant to the medicines.

The most common medicines used to cure TB are

• isoniazid (INH)

• rifampin (RIF)

• ethambutol (Myambutol)

• pyrazinamide

If you have active TB disease of the lungs or throat, you are probably infectious. You need to stay home from work or school so that you don't spread TB bacteria to other people. After taking your medicine for a few weeks, you will feel better and you may no longer be infectious to others.

Having active TB disease should not stop you from leading a normal life. When you are no longer infectious or feeling sick, you can do the same things you did before you had active TB disease.

The medicine that you are taking should not affect your strength, sexual function, or ability to work. If you take your medicine as prescribed, the medicine will kill all the TB bacteria. This will keep you from becoming sick again.

Streptomycin, a drug that is given by injection, may be used as well, particularly when the disease is extensive and/or the patients do not take their oral medications reliably (poor compliance). Treatment usually lasts for many months and sometimes, for years.

Successful treatment of TB is dependent largely on the compliance of the patient. Indeed, the failure of a patient to take the medications is the most important cause of failure to cure the TB infection.

Drug-resistant TB (TB that does not respond to drug treatment) has become a very serious problem in recent years in certain populations.

For example, INH resistant TB is seen among patients from Southeast Asia. The reason for this INH resistance is not quite clear. However, the presence of INH-like substances in the cough syrups in that part of the world may play a role in causing the INH resistance.

An even more serious problem is the multi-drug resistant TB that has been seen in prison populations. Poor compliance by the inmates is thought to be the main reason for this multi-drug resistance.

Surgery on the lungs may be indicated to help cure TB when medication has failed, but in this day and age, surgery for TB is unusual.

Treatment with appropriate antibiotics will usually cure the TB. Without treatment, however, tuberculosis can be a lethal infection. Early diagnosis, therefore, is important.

Those individuals who have been exposed to a person with TB, or suspect that they have been, should be examined by a doctor for signs of TB and screened with a TB skin test.

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What are the side effects of medicines for TB?

If you are taking medicine for TB, you should take it as directed by your doctor or nurse. Occasionally, the medicines may cause side effects. Some side effects are minor problems. Others are more serious. If you have a serious side effect, call your doctor or nurse immediately. You may be told to stop taking your medicine or to return to the clinic for tests.

The side effects listed below are serious. If you have any of these symptoms, call your doctor immediately:

• no appetite

• nausea

• vomiting

• yellowish skin or eyes

• fever for 3 or more days

• abdominal pain

• tingling fingers or toes

• skin rash

• easy bleeding

• aching joints

• dizziness

• tingling or numbness around the mouth

• easy bruising

• blurred or changed vision

• ringing in the ears

• hearing loss

The side effects listed below are minor problems. If you have any of these side effects, you can continue taking your medicine:

• Rifampin can turn urine, saliva, or tears orange. The doctor or nurse may advise you not to wear soft contact lenses because they may get stained.

• Rifampin can make you more sensitive to the sun. This means you should use a good sunscreen and cover exposed areas so you don't burn.

• Rifampin makes birth control pills and implants less effective. Women who take rifampin should use another form of birth control.

If you are taking rifampin as well as methadone (used to treat drug addiction), you may have withdrawal symptoms. Your doctor or nurse may need to adjust your methadone dosage.

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Why do I need to take TB medicine regularly?

TB bacteria die very slowly. It takes at least 6 months for the medicine to kill all the TB bacteria. You will probably start feeling well after only a few weeks of treatment.

But beware! The TB bacteria are still alive in your body. You must continue to take your medicine until all the TB bacteria are dead, even though you may feel better and have no more symptoms of active TB disease.

If you don't continue taking your medicine or you aren't taking your medicine regularly, this can be very dangerous. The TB bacteria will grow again and you will remain sick for a longer time.

The bacteria may also become resistant to the medicines you are taking. You may need new, different medicines to kill the TB bacteria if the old medicines no longer work. These new medicines must be taken for a longer time and usually have more serious side effects.

If you become infectious again, you could give TB bacteria to your family, friends, or anyone else who spends time with you. It is very important to take your medicine the way your doctor or nurse tells you.

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How can I keep from spreading TB?

The most important way to keep from spreading TB is to take all your medicine, exactly as directed by your doctor. You also need to keep all of your clinic appointments! Your doctor needs to see how you are doing.

You may need another chest x-ray or a test of the phlegm you may cough up. These tests will show whether the medicine is working. They will also show whether you can still give TB bacteria to others. Be sure to tell the doctor about anything you think is wrong.

If you are sick enough with active TB disease to go to a hospital, you may be put in a special room. These rooms use air vents that keep TB bacteria from spreading to other rooms.

People who work in these special rooms must wear a special face mask to protect themselves from TB bacteria. You must stay in the room so that you will not spread TB bacteria to other people. Ask a nurse for anything you need that is not in your room.

If you are infectious while you are at home, there are certain things you can do to protect yourself and others near you. Your doctor may tell you to follow these guidelines to protect yourself and others:

• The most important thing is to take your medicine.

• Always cover your mouth with a tissue when you cough, sneeze, or laugh. Put the tissue in a closed bag and throw it away.

• Do not go to work or school. Separate yourself from others and avoid close contact with anyone. Sleep in a bedroom away from other family members.

• Air out your room often to the outside of the building. TB spreads in small closed spaces where air doesn't move. Put a fan in your window to blow out (exhaust) air that may be filled with TB bacteria. If you open other windows in the room, the fan also will pull in fresh air. This will reduce the chances that TB bacteria will stay in the room and infect someone who breathes the air.

Remember, TB is spread through the air. People cannot get infected with TB bacteria through handshakes, sitting on toilet seats, or sharing dishes and utensils with someone who has TB.

After you take medicine for about 2 or 3 weeks, you may no longer be able to spread TB bacteria to others. If your doctor agrees, you will be able to go back to your daily routine.

Remember, you will get well only if you take your medicine exactly as your doctor tells you.

Think about people who may have spent time with you, such as family members, close friends, and coworkers. They need to test them for latent TB infection.

TB is especially dangerous for children and people with HIV infection. If infected with TB bacteria, these people need medicine right away to keep from developing active TB disease.

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What is drug-resistant tuberculosis? Can people with drug-resistant tuberculosis be treated?

If you do not take your medicine as your doctor, the TB bacteria may become resistant to a certain medicine. This means that the medicine can no longer kill the bacteria.

Drug resistance is more common in people who

• have spent time with someone with drug-resistant active TB disease

• do not take their medicine regularly

• do not take all of their medicine as told by their doctor or nurse

• develop active TB disease again, after having taken TB medicine in the past

• come from areas where drug-resistant TB is common

Multidrug-resistant tuberculosis (MDR TB) - sometimes the bacteria become resistant to two or more of the most important medicines:  isoniazid(INH) and rifampin(RIF) - the two most important drugs used to treat tuberculosis) and this presents difficult treatment problems. This is called multidrug-resistant TB, or MDR TB and is a very serious problem.

People with MDR TB disease must be treated with special medicines.  Treatment must be individualized and based on the patient’s medication history and drug resistance studies.  These medicines are not as good as the usual medicines for TB and they may cause more side effects.

Also, most people with MDR TB disease must see a TB expert who can closely observe their treatment to make sure it is working.

People who have spent time with someone sick with MDR TB disease can become infected with these multidrug-resistant bacteria. If they have a positive skin test reaction, they may be given medicine to keep them from developing MDR TB disease. This is very important for people who are at high risk of developing MDR TB disease, such as children and HIV-infected people.

Unfortunately, adequate data are not available on the effectiveness of various regimens and the necessary duration of treatment for patients with organisms resistant to both isoniazid(NIH) and rifampin(RIF).

Moreover, many of these patients also have resistance to other first-line drugs (e.g. , ethambutol and streptomycin). Because of the poor outcome in such cases, it is preferable to give at least three, but often as many as four to six new drugs to which the organism is susceptible.

This regimen should be continued for a total of 18 to 24 months. MDR TB drugs should be given using a daily regimen under directly observed therapy (DOT). Intermittent administration of medications is generally not possible in treatment of MDR TB.

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Can people be vaccinated against tuberculosis?   <more.....>

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