What is pulmonary tuberculosis?

The bacterium Mycobacterium tuberculosis causes tuberculosis (TB), a contagious, airborne infection that destroys body tissue. Pulmonary TB occurs when M. tuberculosis primarily attacks the lungs. However, it can spread from there to other organs. Pulmonary TB is curable with an early diagnosis and antibiotic treatment.

Pulmonary TB, also known as consumption, spread widely as an epidemic during the 18th and 19th centuries in North America and Europe. After the discovery of antibiotics like streptomycin and especially isoniazid, along with improved living standards, doctors were better able to treat and control the spread of TB.

Since that time, TB has been in decline in most industrialized nations. However, TB remains in the top 10 causes of death worldwide, according to the World Health Organization (WHO), with an estimated 95 percent of TB diagnoses as well as TB-related deaths occur in developing countries.

That said, it’s important to protect yourself against TB. Over 9.6 million people have an active form of the disease, according to the American Lung Association (ALA). If left untreated, the disease can cause life-threatening complications like permanent lung damage.

Being exposed to M. tuberculosis doesn’t necessarily mean you’ll get sick. Among the 2.5 billion people who carry the germ, most have latent TB.

People with latent TB aren’t contagious and have no symptoms because their immune system is protecting them from getting sick. But it is possible for latent TB to develop into active TB. Most people with the germ have up to a 15 percent lifetime risk of getting sick with TB. The risk can be far higher if you have conditions that compromise your immune system such as HIV infection. When you start showing symptoms, you may become contagious and have pulmonary TB.

If you’re at risk of being exposed to M. tuberculosis (for example, because you were born in a country where TB is common), you should talk to your doctor about being tested for latent TB infection and being treated if test results are positive.

If you or someone you know has pulmonary TB, they will commonly:

There may also be other symptoms of pulmonary TB, such as fatigue. Your doctor will be able to tell you whether you should be tested for TB after reviewing all your symptoms.

You can’t get pulmonary TB by:

  • shaking hands
  • sharing food or drink
  • sleeping in the same bed
  • kissing

TB is airborne, which means you can become infected with M. tuberculosis after breathing air exhaled by someone with tuberculosis. This can be air from:

  • coughing
  • sneezing
  • laughing
  • singing

The germs can stay in the air for several hours. It’s possible to inhale them even when the infected person isn’t in the room. But usually you have to be close to someone with TB for a long period of time to catch it.

The risk for getting pulmonary TB is highest for people who are in close contact with those who have TB. This includes being around family or friends with TB or working in places such as the following that often house people with TB:

  • correctional facilities
  • group homes
  • nursing homes
  • hospitals
  • shelters

People also at risk for developing pulmonary TB disease are:

During your examination, your doctor will:

  • conduct a physical exam to check for fluid in your lungs
  • ask about your medical history
  • schedule a chest X-ray
  • order a medical test to confirm pulmonary TB

To diagnose pulmonary TB specifically, a doctor will ask a person to perform a strong cough and produce sputum up to three separate times. The doctor will send the samples to a laboratory. At the lab, a technician will examine the sputum under a microscope to identify TB bacteria.

In addition to this test, a doctor can also “culture” a sputum sample. This means they take a portion of the sputum sample and put it in a special material that makes TB bacteria grow. If TB bacteria grow, this is a positive culture.

Doctors can also order a polymerase chain reaction (PCR) assay to be performed. This tests the sputum for the presence of certain genes from the germs that cause TB.

Other exams

These exams can also look for pulmonary TB, which may be hard to diagnose in children, and in people who have HIV or multidrug-resistant TB (MDR-TB).

CT scanan imaging test to check lungs for signs of an infection
bronchoscopya procedure that involves inserting a scope through your mouth or nose to allow your doctor to see your lungs and airways
thoracentesisa procedure that removes fluid from the space between the outside of your lungs and the wall of your chest
lung biopsya procedure to remove a sample of lung tissue

It’s important to get treatment for latent TB even if you have no symptoms. You can still develop pulmonary TB disease in the future. You may only need one TB drug if you have latent TB.

If you have pulmonary TB, your doctor may prescribe several medicines. You’ll need to take these drugs for six months or longer for the best results.

The most common TB medicines are:

  • isoniazid
  • pyrazinamide
  • ethambutol (Myambutol)
  • rifampin (Rifadin)

Your doctor might recommend an approach called directly observed therapy (DOT) to ensure that you complete your treatment. Stopping treatment or skipping doses can make pulmonary TB resistant to medicines, leading to MDR-TB.

With DOT, a healthcare professional meets with you every day or several times a week to administer your medication so that you don’t have to remember to take it on your own.

If you aren’t on DOT, make a schedule for taking your medicines so that you don’t miss a dose. Here are some tips to help you remember to take your medicines:

  • Take medicines at the same time every day.
  • Make a note on your calendar each day to show that you’ve taken your medicine.
  • Ask someone to remind you to take your medicine every day.
  • Keep your medicines in a pill organizer.

You won’t need to go to the hospital unless you’re unable to take the medication at home or have a bad reaction to the treatment.

Multi-drug resistant TB (MDR-TB) is TB that is resistant to the typical antibiotics used to treat the condition, which are isoniazid and rifampin. Some of the factors that contribute to MDR-TB include:

  • healthcare providers prescribing an incorrect drug to treat TB
  • people stopping treatment early
  • people taking poor-quality medications

Improper prescribing is the leading cause of MDR-TB, according to WHO. However, it’s possible a person who hasn’t ever taken TB medications can have a strain that is drug-resistant.

People who develop MDR-TB also have fewer options for treatment. The second-line treatments can be expensive and take as long as two years. It’s also possible for MDR-TB to develop even further into extensively drug-resistant TB (XDR-TB). This is why it’s important to finish your medications, even if you feel better before you finish your dosage.

Pulmonary TB is curable with treatment, but if left untreated or not fully treated, the disease often causes life-threatening concerns. Untreated pulmonary TB disease can lead to long-term damage to these parts of the body:

  • lungs
  • brain
  • liver
  • heart
  • spine

New drugs and treatments are currently being developed to prevent latent TB and TB, especially as MDR-TB grows. In some countries, this involves a vaccine called Bacillus Calmette-Guérin (BCG). This vaccine is useful to prevent severe forms of TB outside the lungs in children, but it doesn’t prevent development of pulmonary TB.

It can be difficult to avoid contracting TB if you work in an environment frequented by people with TB or if you’re caring for a friend or family member with TB.

Following are a few tips for minimizing your risk for pulmonary TB:

  • Provide education on preventing TB like cough etiquette.
  • Avoid extended close contact with someone who has TB.
  • Air out rooms regularly.
  • Cover your face with a mask that is approved for protection against TB.

Anyone exposed to tuberculosis should be tested, even if they show no symptoms. The Centers for Disease Control and Prevention has detailed guidelines and precautions for people who work or visit a healthcare setting.

How to protect others

People with latent TB aren’t contagious and can go about their day-to-day lives as usual.

But if you have pulmonary TB disease, you need to stay home and avoid close contact with others. Your doctor will tell you when you’re no longer contagious and can resume a regular routine.