Tuberculosis

Date Updated: 04/03/2021

Overview

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.

Symptoms

Although your body can harbor the bacteria that cause tuberculosis, your immune system usually can prevent you from becoming sick. For this reason, doctors make a distinction between:

Latent TB. You have a TB infection, but the bacteria in your body are inactive and cause no symptoms. Latent TB, also called inactive TB or TB infection, isn't contagious. Latent TB can turn into active TB, so treatment is important.
Active TB. Also called TB disease, this condition makes you sick and, in most cases, can spread to others. It can occur weeks or years after infection with the TB bacteria.

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.

When to see a doctor

See your doctor if you have a fever, unexplained weight loss, drenching night sweats or a persistent cough. These are often indications of TB but can also result from other conditions. Also, see your doctor if you think you've been exposed to TB.

The Centers for Disease Control and Prevention recommends that people who have an increased risk of tuberculosis be screened for latent TB infection. This recommendation includes people who:

Have HIV/AIDS
Use IV drugs
Are in contact with infected people
Are from a country where TB is common, such as several countries in Latin America, Africa and Asia
Live or work in areas where TB is common, such as prisons or nursing homes
Work in health care and treat people with a high risk of TB
Are children who are exposed to adults at risk of TB

Causes

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.

Risk factors

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.

Complications

Without treatment, tuberculosis can be fatal. Untreated active disease typically affects your lungs, but it can affect other parts of your body, as well.

Tuberculosis complications include:

Spinal pain. Back pain and stiffness are common complications of tuberculosis.
Joint damage. Arthritis that results from tuberculosis (tuberculous arthritis) usually affects the hips and knees.
Swelling of the membranes that cover your brain (meningitis). This can cause a lasting or intermittent headache that occurs for weeks and possible mental changes.
Liver or kidney problems. Your liver and kidneys help filter waste and impurities from your bloodstream. Tuberculosis in these organs can impair their functions.
Heart disorders. Rarely, tuberculosis can infect the tissues that surround your heart, causing inflammation and fluid collections that might interfere with your heart's ability to pump effectively. This condition, called cardiac tamponade, can be fatal.

Prevention

If you test positive for latent TB infection, your doctor might advise you to take medications to reduce your risk of developing active tuberculosis. Only active TB is contagious.

Protect your family and friends

If you have active TB, it generally takes a few weeks of treatment with TB medications before you're not contagious anymore. Follow these tips to help keep your friends and family from getting sick:

Stay home. Don't go to work or school or sleep in a room with other people during the first few weeks of treatment.
Ventilate the room. Tuberculosis germs spread more easily in small closed spaces where air doesn't move. If it's not too cold outdoors, open the windows and use a fan to blow indoor air outside.
Cover your mouth. Use a tissue to cover your mouth anytime you laugh, sneeze or cough. Put the dirty tissue in a bag, seal it and throw it away.
Wear a face mask. Wearing a face mask when you're around other people during the first three weeks of treatment may help lessen the risk of transmission.

Finish your medication

This is the most important step you can take to protect yourself and others from tuberculosis. When you stop treatment early or skip doses, TB bacteria have a chance to develop mutations that allow them to survive the most potent TB drugs. The resulting drug-resistant strains are deadlier and more difficult to treat.

Vaccinations

In countries where tuberculosis is more common, infants often are vaccinated with bacille Calmette-Guerin (BCG) vaccine. The BCG vaccine isn't recommended for general use in the United States because it isn't very effective in adults. Dozens of new TB vaccines are in various stages of development and testing.

Diagnosis

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

The most commonly used diagnostic tool for tuberculosis is a skin test, though blood tests are becoming more commonplace. A small amount of a substance called tuberculin is injected just below the skin on the inside of your 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 don't. It can also indicate that people don't have TB when they do.

You can have a false-positive result if you've been vaccinated recently with the bacille 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 also can occur.

Blood tests

Blood tests can confirm or rule out latent or active tuberculosis. These tests measure your immune system's reaction to TB bacteria.

These tests require only one office visit. A blood test might 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 might show white spots in your lungs where your immune system has walled off TB bacteria, or it might reveal changes in your lungs caused by active tuberculosis.

Sputum tests

If your chest X-ray shows signs of tuberculosis, your doctor might 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. Getting results of these tests can take four to eight weeks.

Treatment

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.

Coping and support

Your physical health can affect your mental health. Denial, anger and frustration are normal when you must deal with something as challenging as tuberculosis. Talking to someone such as a therapist might help you develop coping strategies.

Preparing for an appointment

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

What you can do

When you make the appointment, ask if there's anything you need to do in advance.

Make a list of:

Your symptoms, including any that may seem unrelated to the reason for which you scheduled the appointment, and when they began
Key personal information, including recent life changes or international travel
All medications, vitamins or supplements you take, including doses
Questions to ask your doctor

For tuberculosis, some basic questions to ask your doctor include:

What's the most likely cause of my symptoms?
Do I need 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 is likely to ask you some questions, such as:

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 illicit drugs?