Pulmonary Tuberculosis

Pulmonary tuberculosis is a serious bacterial infection that mainly affects the lungs but can spread to other parts of the body. While highly contagious, it is both preventable and curable with proper treatment using antibiotics, though the infection requires long-term medication lasting several months.

Table of contents

• What is pulmonary tuberculosis?
• What causes pulmonary tuberculosis and how does it spread?
• Types of TB infection
• Who is at higher risk?
• Signs and symptoms
• How tuberculosis is diagnosed
• Treatment for pulmonary tuberculosis
• Preventing the spread of tuberculosis
• Outlook and recovery

What is pulmonary tuberculosis?

Pulmonary tuberculosis (TB) is a serious infection caused by a type of bacteria called Mycobacterium tuberculosis. The word “pulmonary” means it mainly affects the lungs, though the bacteria can spread through the blood to other parts of the body, such as the kidneys, spine, and brain^[1][3].

TB has been a human disease for thousands of years. Before the COVID-19 pandemic, tuberculosis was the world’s most common infectious disease^[6]. Every year, 10 million people fall ill with tuberculosis worldwide, and despite being preventable and curable, 1.5 million people die from TB each year, making it the world’s top infectious killer^[7].

What causes pulmonary tuberculosis and how does it spread?

Pulmonary TB is caused by the bacterium Mycobacterium tuberculosis. TB is contagious, which means the bacteria can spread from an infected person to someone else through the air^[1].

TB germs can get into the air when a person with active TB disease of the lungs or throat coughs, speaks, sings, sneezes, or laughs. These tiny droplets containing the bacteria can stay in the air for several hours, depending on the environment^[5]. People nearby may breathe in these germs and become infected. You can get TB by breathing in air droplets from a cough or sneeze of an infected person^[1].

TB germs are more likely to spread in indoor areas or other places with poor air circulation, such as a closed vehicle, than in outdoor areas^[5]. You usually have to spend a lot of time in contact with someone who’s contagious to catch TB^[3].

TB germs are not spread by shaking someone’s hand, sharing food or drink, touching bed linens or toilet seats, sharing toothbrushes, or kissing^[5].

Types of TB infection

Not everyone who is infected with TB bacteria gets sick. There are two main forms of TB infection: inactive TB (also called latent TB) and active TB disease^[3].

Inactive tuberculosis (latent TB infection) means that TB germs can live in the body without making you sick. This is called a latent TB infection. Immune system cells build a wall around lung tissue with TB germs, and the germs can’t do any more harm if the immune system keeps them under control^[4]. If you’re infected but have no symptoms, it’s called inactive tuberculosis. TB is dormant, or sleeping, inside your body. As many as 13 million people in the United States have latent TB^[3]. People with inactive TB are infected with TB germs, but they do not feel sick, do not have symptoms of TB disease, and cannot spread TB germs to others^[5].

Most people recover from a primary TB infection without further evidence of the disease. The infection may stay inactive for years. In some people, it becomes active again, which is called reactivation^[1]. About a quarter of the global population is estimated to have been infected with TB bacteria, but most people will not go on to develop TB disease and some will clear the infection^[7].

Active TB disease happens when the immune system can’t control an infection. TB germs become active, multiplying in the body. When TB germs are active, this is called active TB disease^[5]. People with active TB disease feel sick and may also be able to spread the germs to people they spend time with every day. Without treatment, active TB disease can be fatal^[5].

Without treatment, people with inactive TB can develop active TB disease at any time. People with weakened immune systems are at very high risk of developing active TB disease once infected with TB germs^[5].

Who is at higher risk?

Anyone can get TB, but some people are at higher risk of being exposed to TB germs or developing active TB disease once infected^[17].

You have a higher risk of being exposed to TB germs if you^[17]:

• Were born in or frequently travel to countries where TB is common, including some countries in Asia, Africa, and Latin America
• Live or used to live in large group settings where TB is more common, such as homeless shelters, prisons, or jails
• Recently spent time with someone who has active TB disease
• Work in places where TB is more likely to spread, such as hospitals, homeless shelters, correctional facilities, and nursing homes
• Are around people who have TB, live in crowded or unclean living conditions, or have poor nutrition^[1]

You have a higher risk of developing active TB disease once infected if you^[17]:

• Were recently infected with TB germs
• Have a weaker immune system because of certain medications or health conditions such as diabetes, cancer, or HIV

The following people are at higher risk of active TB or reactivation of TB^[1]:

• Older adults
• Infants
• People with weakened immune systems, for example due to HIV/AIDS, chemotherapy, diabetes, or medicines that weaken the immune system

Several conditions that cause weakened immune systems can make people more susceptible to TB, including diabetes, medicines to treat an autoimmune disease, chemotherapy for cancer, and HIV disease^[2].

Signs and symptoms

The primary stage of TB does not cause symptoms. When symptoms of pulmonary TB occur, they often come on gradually and can include^[1][7]:

• A cough that lasts more than 3 weeks (usually with mucus, sometimes with blood)
• Coughing up blood or mucus
• Chest pain
• Breathing difficulty
• Fever or high temperature
• Night sweats or excessive sweating, particularly at night
• Fatigue, tiredness, or weakness
• Loss of appetite
• Weight loss
• Chills
• Wheezing

Often, these symptoms will be mild for many months, leading to delays in seeking care and increasing the risk of spreading the infection to others^[7].

If TB has spread to another part of the body such as your glands, bones, brain, or other organs, you may also have other symptoms, including swollen glands, body aches and pains, swollen joints or ankles, stomach or pelvic pain, constipation, dark or cloudy urine, headache, being sick, feeling confused, a stiff neck, or a rash on the legs, face, or other part of the body^[19].

You won’t have symptoms if you have inactive TB. But you might have a positive TB test^[3].

How tuberculosis is diagnosed

Your health care provider will perform a physical exam, which may show clubbing of the fingers or toes in people with advanced disease, swollen or tender lymph nodes in the neck or other areas, fluid around a lung, or unusual breath sounds in the lungs^[1].

Screening tests are used to check if you have been exposed to TB bacteria. These include^[1][3]:

• Tuberculin skin test (also called a PPD test or Mantoux test): A tiny amount of a substance called tuberculin is injected just below the skin on the inside of one forearm. Within 48 to 72 hours, a healthcare worker will check your arm for swelling at the injection site. The size of the raised skin is used to determine a positive or negative test^[11].
• Interferon-gamma release blood test (such as the QFT-Gold test): A sample of blood is sent to a lab to find out whether certain immune system cells can “recognize” tuberculosis^[1][11].

A positive test shows that you have been exposed to TB bacteria and likely have either a latent TB infection or active TB disease. A negative test means that your body didn’t react to the test, though it doesn’t necessarily mean you don’t have an infection^[11].

If the healthcare provider suspects a patient to have TB disease, they will send the patient for additional testing. Tests that may be ordered include^[1][11]:

• Chest X-ray: Can show irregular patches in the lungs that are typical of active TB disease
• Chest CT scan: Provides more detailed imaging of the lungs
• Sputum examination and cultures: Sputum is mucus or phlegm that you cough up from deep inside your lungs. Lab tests can detect TB bacteria in sputum samples. If you have active TB in your lungs or voice box, sputum samples can be tested^[7].
• Bronchoscopy: A test that uses a scope to view the airways and collect samples from them
• Thoracentesis: A procedure to remove fluid from the space between the lining of the outside of the lungs and the wall of the chest
• Biopsy of the affected tissue (rarely required)

Treatment for pulmonary tuberculosis

The goal of treatment is to cure the infection with medicines that fight TB bacteria. Both active and inactive tuberculosis should be treated^[1][3].

Treatment for latent TB infection typically involves taking antibiotics for 3 to 6 months. A standard treatment regimen is taking the antibacterial drug isoniazid for six to nine months^[2]. If you have inactive TB, treating it is the best way to prevent active TB disease^[5].

Treatment for active pulmonary TB is treated with a combination of many medicines, usually 4 medicines^[1]. The most commonly used medicines are^[3][8]:

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

Once the TB isolate is known to be fully susceptible, ethambutol can be discontinued^[8]. After 2 months of therapy for a fully susceptible isolate, pyrazinamide can be stopped. Isoniazid plus rifampin are continued as daily or intermittent therapy for 4 more months^[8].

You may need to take many different pills at different times of the day for 6 months or longer. Treatment for drug-susceptible TB disease typically takes 4, 6, or 9 months depending on the regimen^[8]. It is very important that you take the pills the way your provider instructed. You’ll have to take these medications for a long time. You must take them exactly as your provider prescribes to get rid of all the bacteria. It’s very important to finish your entire prescription^[3][1].

When people do not take their TB medicines like they are supposed to, the infection can become much more difficult to treat. The TB bacteria can become resistant to treatment, which means the medicines no longer work^[1].

Directly observed therapy (DOT) is recommended for all patients. With DOT, a nurse or public health worker may need to watch you take the prescribed medicines. This approach ensures that you’ll take the needed medicine on schedule, which is the best way to ensure you will be cured of TB^[1][8].

If TB has spread to your brain, spinal cord, or the area around your heart, you may also need to take steroid medicine for a few weeks^[19].

You may need to stay at home or be admitted to a hospital for 2 to 4 weeks to avoid spreading the disease to others until you are no longer contagious^[1].

Your provider is required by law to report your TB illness to the local health department. Your health care team will ensure that you receive the best care^[1].

Preventing the spread of tuberculosis

If you have been exposed to a person with an active TB infection, contact your health care provider or health department. Be sure to tell the health care provider when you spent time with the person who has active TB disease^[17].

If you have untreated TB disease that can spread from person to person (TB disease in the lungs or throat), your health care provider may ask you to stay in home isolation. Home isolation means you avoid contact with other people to help stop the spread to others. Young children and people with weak immune systems are at the highest risk of getting sick^[18].

If you are in home isolation, you should^[18][20][21]:

• Remain in your home and avoid contact with others
• Take your medicines as directed, eat healthy foods, and get plenty of rest
• Always cover your mouth and nose with a tissue when you cough, sneeze, or laugh
• Wear a mask that covers your nose and mouth if you must go to medical appointments and when health care providers come to your home
• Air out rooms you are staying in by opening the window (if the weather allows)
• Tell any new health care providers (such as ambulance paramedics) that you have contagious TB disease
• Not have visitors, especially children and people with weak immune systems
• Not use buses, trains, taxis, or airplanes
• Not go to public places like work, school, church, stores, shopping malls, restaurants, or movie theaters
• Cancel or reschedule non-medical appointments until after your home isolation has ended

If you can, use a fan or open the windows in your home. This helps to move the air around. You may go outside of your home in the open air without your mask^[21].

You should not be around babies, young children, or people who have a weak immune system from diseases like HIV or cancer. This is because they have a hard time fighting infections^[21].

The length of time for home isolation is different for each person. Your health care provider will let you know how long you need to stay at home. The duration of treatment and results of your sputum tests will help your health care provider decide when you can stop home isolation^[18].

You can protect your family and friends by following the home isolation instructions and by taking your TB medications. You can also help protect your family and friends by making sure they get tested for TB^[18].

There is a vaccine for tuberculosis called the BCG vaccine. It’s recommended for some people who are at higher risk of catching TB or getting seriously ill from it^[19].

Outlook and recovery

Symptoms often improve in 2 to 3 weeks after starting treatment^[1]. You will start to feel better after taking your medicine for a few weeks. And you may not be able to infect others at this point. But don’t go back to work or school until your doctor tells you it’s okay^[16].

Given full treatment with an appropriate regimen, almost all patients will recover and be cured^[8]. With TB, you can live a normal life, both during and after treatment^[22].

You can ease the stress of illness by joining a support group. Sharing with others who have common experiences and problems can help you feel more in control^[1].