About tuberculosis (tb)

What is tuberculosis (tb)?

Tuberculosis (TB) is a potentially serious infectious disease that mainly affects the lungs. The bacteria that cause tuberculosis are spread from person to person through tiny droplets released into the air via coughs and sneezes.

Once rare in developed countries, tuberculosis infections began increasing in 1985, partly because of the emergence of HIV, the virus that causes AIDS. HIV weakens a person's immune system, so it can't fight the TB germs. In the United States, because of stronger control programs, tuberculosis began to decrease again in 1993. But it remains a concern.

Many tuberculosis strains resist the drugs most used to treat the disease. People with active tuberculosis must take many types of medications for months to get rid of the infection and prevent antibiotic resistance.

What are the symptoms for tuberculosis (tb)?

Signs and symptoms of active TB include:

  • Coughing for three or more weeks
  • Coughing up blood or mucus
  • Chest pain, or Pain with breathing or coughing
  • Unintentional weight loss
  • Fatigue
  • Fever
  • Night sweats
  • Chills
  • Loss of appetite

Tuberculosis can also affect other parts of your body, including the kidneys, spine or brain. When TB occurs outside your lungs, signs and symptoms vary according to the organs involved. For example, tuberculosis of the spine might cause back pain, and tuberculosis in your kidneys might cause blood in your urine.

What are the causes for tuberculosis (tb)?

Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs or sings.

Although tuberculosis is contagious, it's not easy to catch. You're much more likely to get tuberculosis from someone you live or work with than from a stranger. Most people with active TB who've had appropriate drug treatment for at least two weeks are no longer contagious.

HIV and TB

Since the 1980s, tuberculosis cases have increased dramatically because of the spread of HIV, the virus that causes AIDS. HIV suppresses the immune system, making it difficult for the body to control TB bacteria. As a result, people with HIV are much more likely to get TB and to progress from latent to active disease than are people who aren't HIV positive.

Drug-resistant TB

Tuberculosis also remains a major killer because of the increase in drug-resistant strains. Over time, some TB germs have developed the ability to survive despite medications. This is partly because people don't take their drugs as directed or don't complete the course of treatment.

Drug-resistant strains of tuberculosis emerge when an antibiotic fails to kill all of the bacteria it targets. The surviving bacteria become resistant to that drug and often other antibiotics as well. Some TB bacteria have developed resistance to the most commonly used treatments, such as isoniazid and rifampin (Rifadin, Rimactane).

Some TB strains have also developed resistance to drugs less commonly used in TB treatment, such as the antibiotics known as fluoroquinolones, and injectable medications including amikacin and capreomycin (Capastat). These medications are often used to treat infections that are resistant to the more commonly used drugs.

What are the treatments for tuberculosis (tb)?

If you have latent TB, your doctor might recommend treatment with medication if you're at high risk of developing active TB. For active 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 and where the infection is in your body.

Most common TB drugs

If you have latent tuberculosis, you might need to take only one or two types of TB drugs. 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 or capreomycin (Capastat), are generally used for 20 to 30 months. Some types of TB are developing resistance to these medications as well.

Some drugs might be added to therapy to counter drug resistance, including:

  • Bedaquiline (Sirturo)
  • Linezolid (Zyvox)

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 toxic to your liver. When taking these medications, call your doctor immediately if you have any of the following:

  • Nausea or vomiting
  • Loss of appetite
  • A yellow color to your skin (jaundice)
  • Dark urine
  • Easy bruising or bleeding
  • Blurred vision

Completing treatment is essential

After a few weeks, you won't be contagious and you might start to feel better. Don't stop taking your TB drugs — you must 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.

A program called directly observed therapy (DOT) can help people stick to their treatment regimen. A health care worker gives you your medication so that you don't have to remember to take it on your own.

What are the risk factors for tuberculosis (tb)?

Anyone can get tuberculosis, but certain factors can increase your risk, including:

Weakened immune system

A healthy immune system often successfully fights TB bacteria. However, several conditions and medications can weaken your immune system, including:

  • HIV/AIDS
  • Diabetes
  • Severe kidney disease
  • Certain cancers
  • Cancer treatment, such as chemotherapy
  • Drugs to prevent rejection of transplanted organs
  • Some drugs used to treat rheumatoid arthritis, Crohn's disease and psoriasis
  • Malnutrition or low body weight
  • Very young or advanced age
Traveling or living in certain areas

Your risk of getting tuberculosis is higher if you live in, emigrate from or travel to areas with high tuberculosis rates. Areas include:

  • Africa
  • Asia
  • Eastern Europe
  • Russia
  • Latin America
Other factors
  • Using substances. IV drugs or excessive alcohol use weakens your immune system and makes you more vulnerable to tuberculosis.
  • Using tobacco. Tobacco use greatly increases the risk of getting TB and dying of it.
  • Working in health care. Regular contact with people who are ill increases your chances of exposure to TB bacteria. Wearing a mask and frequent hand-washing greatly reduce your risk.
  • Living or working in a residential care facility. People who live or work in prisons, homeless shelters, psychiatric hospitals or nursing homes are all at a higher risk of tuberculosis due to overcrowding and poor ventilation.
  • Living with someone infected with TB. Close contact with someone who has TB increases your risk.

Video related to tuberculosis (tb)