ARDS is a life-threatening illness in which the lungs are severely inflamed. Swelling throughout the lungs causes tiny blood vessels to leak fluid and the air sacs (alveoli) collapse or fill with fluid, preventing the lungs from working well. Patients with ARDS have problems getting enough oxygen into their blood, and getting rid of carbon dioxide, so they must be given extra oxygen and will usually need a ventilator to breathe. Despite intensive treatment, about 40% of people with ARDS die from the disease.

Adenovirus is a type of virus that can cause a variety of illnesses such as upper and lower respiratory infections, gastrointestinal infection, neurological infection, and eye infection. In some cases, it is severe enough to even cause death.

Allergic bronchopulmonary aspergillosis (called ABPA for short) is a problem in the lungs that is not very common. It is caused by a severe allergic reaction after being exposed to a type of fungus called Aspergillus.

Exposure to asbestos is most common in the workplace but is also common in the military and even in the home. Being exposed to asbestos can lead to asbestos-related diseases including pleural plaques, asbestosis, lung cancer, and mesothelioma. Occupational exposure is the No. 1 cause of asbestos disease.

Aspergillosis is an infection caused by a fungus called Aspergillus. The Aspergillus mold lives in soil, plants, and rotting material. It can also be found in the dust in your home, carpeting, heating and air conditioning ducts, certain foods including dried fish, and in marijuana.

Asthma is a chronic disease that affects the airways of your lungs. Your airways are the breathing tubes that carry air in and out of your lungs. When you have asthma, your airways become swollen. This swelling (inflammation) causes the airways to make thick, sticky secretions called mucus. Asthma also causes the muscles in and around your airways to get very tight or constrict. This swelling, mucus, and tight muscles can make your airways narrower than normal and it becomes very hard for you to get air into and out of your lungs.

Blastomycosis is a disease caused by breathing in a fungus named Blastomyces dermatitidis. This fungus is found in the moist soil of rotting plants or wood. Blastomyces dermatitidis is found in Central and Southeastern United States (the darkened area on the map) and parts of Canada. There has been an increase in the rate of blastomycosis in North America in the last 10 years.

Bronchiectasis (bron-kee-eck-tuh-sis) is a lung condition that causes cough, sputum production, and recurrent respiratory infections. The symptoms are caused by abnormal dilation (widening) of the airways of the lung (bronchi). In some cases, only one airway is affected. In other cases, many are affected. In very severe cases, dilation of the airways occurs throughout the lungs.

BOS is a lung problem that can occur after lung transplantation and is the most common form of chronic lung transplant rejection. Up to half of lung transplant recipients develop BOS within five years of transplantation. When BOS develops, a person will have a progressive loss of lung function when compared to the highest function after transplantation.

BPD is a chronic lung disease that occurs in some babies who are born early (premature). BPD is also called chronic lung disease (CLD) of neonates. It is a condition defined as the need for supplemental oxygen therapy for more than 28 days in children born under 32 weeks gestation and is seen most often in babies who are born before 28 weeks of pregnancy (7 months gestation).

COPD is a preventable and treatable lung disease. People with COPD must work harder to breathe, which can lead to shortness of breath and/or feeling tired. Early in the disease, people with COPD may feel short of breath when they exercise. As the disease progresses, it can be hard to breathe out (exhale) or even breathe in (inhale). A person with COPD may have obstructive bronchiolitis (bron-kee-oh-lite-is), emphysema, or a combination of both conditions. The amount of each of these conditions differs from person to person. Asthma is another disease that causes narrowing of the airways, making it hard to breathe at times, but asthma is not included in the definition of COPD.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a condition where there is elevated blood pressure in the pulmonary arteries caused by chronic blood clots (thromboembolic), which obstruct the free flow of blood through the lungs.

Congenital Central Hypoventilation Syndrome (CCHS) is a rare disorder of the Autonomic Nervous System (ANS) and control of breathing. CCHS is caused by a mutation in the PHOX2B gene. The abnormal gene leads to problems in ANS development. The ANS is part of the body’s nervous system that controls body functions that happen automatically (that is without thinking) to keep us alive. The ANS controls the regulation of breathing, heartbeat, blood pressure, intestinal motility, temperature, and more. All organ systems are served by the ANS.

Cystic fibrosis is a progressive, genetic disease that causes persistent lung infections and limits the ability to breathe over time. In people with CF, mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause the CFTR protein to become dysfunctional. When the protein is not working correctly, it’s unable to help move chloride -- a component of salt -- to the cell surface. Without the chloride to attract water to the cell surface, the mucus in various organs becomes thick and sticky. In the lungs, the mucus clogs the airways and traps germs, like bacteria, leading to infections, inflammation, respiratory failure, and other complications. For this reason, minimizing contact with germs is a top concern for people with CF.

Emphysema is a chronic lung condition in which the air sacs (alveoli) may be collapsed, destroyed, narrowed, overinflated, or stretched. Overinflation of the air sacs is a result of a breakdown of the alveoli walls. It causes a decrease in respiratory function and breathlessness. Damage to the air sacs can't be fixed. It causes permanent holes in the lower lung tissue.

The flu is a type of germ (called a virus) that you breathe in. It can get into the nose, throat, and lungs. Flu is also called influenza (in-floo- EN-zuh). The flu illness is caused by influenza viruses. There are many different strains (types) of this virus. All strains are named starting with an A or B type (such as Influenza A H1N1 or Influenza A H3N2). This season there are vaccines available that include four strains of the flu virus (quadrivalent) as well as vaccines that include only three strains (trivalent). The strains that are included are the ones likely to appear this season and will give you protection. Flu viruses are constantly changing, so it is not unusual for new flu strains to appear and result in the flu even though you may have gotten the vaccine. Despite this, it is important to get a new flu vaccine every year.

Histoplasmosis is an infection caused by inhaling a fungus called Histoplasma capsulatum. Histoplasmosis mainly affects your lungs but can also affect your bone marrow, adrenal glands, gastrointestinal tract (stomach, intestines), brain, and joints. Histoplasmosis can be found in bird and bat droppings (feces) as well as damp soil rich in decayed material. This material is often found in chicken coops, caves, abandoned buildings, and around large trees and shrubs. Histoplasmosis is also called the Ohio River Valley Fever because many people in this area of the U.S. get this infection.

Pulmonary fibrosis (PF) describes a group of lung diseases in which thickening of the walls of the air sacs (called alveoli), caused by scarring, can result in cough, shortness of breath, fatigue, and low blood oxygen levels. Pulmonary fibrosis can be caused by an identifiable irritation to the lungs, but in many cases the cause is unknown. In cases when the cause of PF is unknown, the diagnosis is idiopathic pulmonary fibrosis (IPF). Idiopathic means there is no known cause at this time.

Interstitial lung disease refers to a group of about 100 chronic lung disorders characterized by inflammation and scarring that make it hard for the lungs to get enough oxygen. The scarring is called pulmonary fibrosis. The symptoms and course of these diseases may vary from person to person. The common link between the many forms of the disease is that they all begin with inflammation.

Stridor is a high pitched, noisy, or squeaky sound that occurs during inspiration (breathing in). Laryngomalacia is the most common cause of chronic stridor in infants. The stridor from laryngomalacia is generally mild but it becomes louder when babies cry or get excited. It can also be heard while feeding. Stridor due to laryngomalacia is usually more noticeable when babies are laying or sleeping on their back (supine), and it may disappear by changing position. In about 10% of cases, symptoms worsen while the babies are asleep.

Exercise-induced laryngeal obstruction (EILO) is a breathing problem that affects people during exercise. EILO is defined by an inappropriate narrowing of the upper airway at the level of the vocal cords (glottis) and/or supraglottis (above the vocal cords). This can make it hard to get air into your lungs during exercise and cause a noisy breathing that can be frightening. EILO has also been called vocal cord dysfunction (VCD) or paradoxical vocal fold motion (PVFM).

Legionnaires’ disease (also called legionellosis) is an infection of the lung (pneumonia) that can lead to difficulty breathing, respiratory failure, or even death. Infectious outbreaks are commonly associated with exposure to water supplies contaminated with Legionella (such as air conditioners).

Lung cancer is the leading cause of cancer deaths in the United States and will claim more lives this year than cancer of the breast, prostate, and colon combined. Symptoms of lung cancer can vary from person to person. You may have no symptoms at all or you may feel like you have bronchitis or a bad cold that does not get better. Symptoms which should alert you to see your healthcare provider are: a cough that gets worse or does not go away, more trouble breathing (shortness of breath) than usual, coughing up blood, chest pain, hoarse voice, frequent lung infections, feeling tired all the time, weight loss for no known reason, or swelling of your face or arms. Some people do not recall having any symptoms.

Commonly called a “spot on the lung” or a “shadow,” a nodule is a round area that is more solid than normal lung tissue. It shows up as a white spot on a CT scan. Lung nodules are usually caused by scar tissue, a healed infection that may never have made you sick, or some irritant in the air. Sometimes, a nodule can be an early lung cancer.

Lymphangioleiomyomatosis (lim-FAN-jee-oh-ly-oh-my-oh-ma-TOE-sis), also known as LAM, is a rare lung disease that mainly affects women, usually during their childbearing years. LAM occurs in 3-8 women per million in the general population. LAM is caused by mutations in the tuberous sclerosis complex (TSC) genes. These mutations lead to the growth of abnormal cells that spread by the bloodstream and make their way into the lungs. Once in the lungs, these cells create holes in the lung tissue (called cysts) that can weaken breathing and the ability to take up oxygen.

A malignant pleural effusion (MPE) is the buildup of fluid and cancer cells that collects between the chest wall and the lung. This can cause you to have chest discomfort as well as feel short of breath. It is a fairly common complication in a number of different cancers.

Measles, also known as rubeola, is a disease caused by the measles virus. Before routine measles vaccination began in 1963, nearly all children got infected with measles. Once the measles vaccine became widespread, the number of measles cases dropped to fewer than 150 cases per year from 2001 to 2010. Since 2012, however, the number of U.S., as well as worldwide, measles cases has increased dramatically. This is a major public health concern because of how easily the virus spreads and how serious the infection can be.

Mesothelioma is a rare, aggressive form of cancer that develops in the linings of the lungs, abdomen, or heart. Exposure to asbestos is the only known cause of malignant mesothelioma. The average life expectancy of mesothelioma patients is 12 – 21 months after diagnosis. Symptoms can include chest pain, shortness of breath, and general fatigue.

NTM are bacteria that are normally present in the environment. Inhalation of these bacteria may cause disease in both healthy patients and those with compromised immune systems. NTM disease most often affects the lungs in adults, but it may also affect any body site. Person-to-person transmission of NTM disease is very uncommon, in contrast to the transmission of tuberculosis (Mycobacteria tuberculosis), which is common. The number of people with NTM disease is increasing worldwide.

OHS is a breathing disorder in obese people that leads to low oxygen levels and too much carbon dioxide in your blood. Low oxygen and high carbon dioxide levels may develop because of a condition called hypoventilation during the day (daytime hypoventilation). Hypoventilation means you are not moving enough air in and out of your lungs very well. The three main characteristics of OHS are: 1) obesity; 2) daytime hypoventilation (difficulty getting rid of carbon dioxide); and 3) sleep-disordered breathing (such as obstructive sleep apnea).

The term "obstructive bronchiolitis" covers different clinicopathological aspects. On the one hand, it refers to "small airways disease", where bronchiolar narrowings are widespread, secondary to post inflammatory fibrotic changes linked to tobacco smoke or fibrogenic dust inhalation. These obstructive changes at the level of small airways are responsible for a fixed airflow limitation. The specificity and sensibility of functional tests designed for early detection of such an obstruction are still controversial. On the other hand, the entity covers a disease described at the beginning of the century under the name "bronchiolitis obliterans". It usually appears as a consequence of various causes: viral infection, toxins acting either inhalation or by systemic route, immunological mechanisms as in connective tissue diseases, or in graft versus host reactions. A special emphasis is put on idiopathic bronchiolitis obliterans associated with organizing pneumonia.

Most types of lung disease can be caused by work exposures including: asthma, chronic obstructive pulmonary disease (COPD), interstitial lung diseases, lung cancer, pulmonary infections, and pleural disease. It is important to recognize whether exposures in your workplace are contributing to your lung disease because often steps can be taken to prevent the lung disease or keep it from progressing.

Pertussis is a very contagious respiratory infection commonly known as ‘whooping cough’. It is caused by a bacterium called Bordetella pertussis. The infection became much less common after a successful vaccine was developed and given to children to help prevent infection. However, in recent years, the number of people infected with pertussis has increased and now is at the highest rate seen since the 1950s.

Pleural effusion, sometimes referred to as “water on the lungs,” is the build-up of excess fluid between the layers of the pleura outside the lungs. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing. Normally, a small amount of fluid is present in the pleura.

Pneumonia (nu-mo’ne-a) is inflammation of the air sacs in the lungs in response to an injury, like an infection. When the airways are also involved, it may be called bronchopneumonia. Pneumonia can be in one area of a lung or be in several areas (“double” or “multilobar” pneumonia). Many things can cause pneumonia—though most often they are infectious.

Primary ciliary dyskinesia (PCD) is a rare, inherited, genetic disorder of motile (moving) cilia. Cilia are tiny hairlike structures on the cells in the body. Motile cilia perform an important role in the nose, ears, and airways within the lungs, working to remove unwanted inhaled particles and germs. PCD causes frequent respiratory infections starting at a very early age that results in lifelong, progressive lung, sinus, and ear disease. People with PCD benefit from early diagnosis and treatment to hopefully limit permanent lung damage. PCD diagnosis remains challenging, but faster and more reliable diagnostic methods and the development of expert centers around the world are improving both diagnosis and care for people with PCD.

Pulmonary alveolar proteinosis, commonly known as PAP, is a rare lung syndrome that occurs in about seven people per million in the general population, affecting both men and women of all ethnicities, regardless of socioeconomic class. Although primarily affecting people 30 to 50 years old, PAP can occur at any age. In PAP, there is the buildup of surfactant in the air sacs of the lungs (alveoli) that leads to problems getting oxygen into the body. Surfactant, a naturally produced fluid in the lungs, is normally present in the lungs at a certain level, yet if extra surfactant is not cleared properly, it can build up and cause difficulty breathing and other respiratory issues.

A pulmonary embolism (PE) is a blood clot that gets into blood vessels in the lungs and prevents normal flow of blood in that area. This blockage causes problems with gas exchange. Depending on how big a clot and number of vessels involved, it can be a life-threatening event.

With PAH, the arteries become too narrow to handle the amount of blood that must be pumped through the lungs. This causes several things to happen: a backup of blood in the veins returning blood to the heart; an increase in the pressure that the right side of your heart has to pump against to push blood through your lungs; and a strain on the right side of your heart due to the increased work that it has to do. If this increased pressure is not treated, the right side of your heart can become overworked, become very weak and may possibly fail. Because the blood has difficulty getting through the lungs to pick up oxygen, your blood oxygen level may be lower than normal. This can put a strain not only on your heart but also decrease the amount of oxygen getting to your brain. If your health care provider thinks you may have PAH, they will order tests to see if there is a strain on the right side of your heart. Usually, the first test they order will be an ultrasound of your heart (echocardiogram).

Respiratory syncytial (sin-SI-shul) virus, or RSV, is a common respiratory virus that infects the lungs and breathing passages. It usually causes a mild cold-like illness (upper respiratory infection). In some people, RSV infection moves down into the lungs causing acute bronchiolitis (an inflammation of the airways) or pneumonia. Very young infants are at higher risk of having a lung infection rather than just a cold.

Allergic rhinitis is a diagnosis associated with a group of symptoms affecting the nose. These symptoms occur when you breathe in something you are allergic to, such as dust, animal dander, or pollen. Symptoms can also occur when you eat food that you are allergic to. Allergic rhinitis is commonly called hay fever or seasonal allergy.

At least one out of three people with rhinitis symptoms do not have allergies. Nonallergic rhinitis usually afflicts adults and causes year-round symptoms, especially runny nose and nasal congestion. This condition differs from allergic rhinitis because the immune system is not involved.

Sarcoidosis (sar-coy-DOE-sis) is a disease of unknown cause in which inflammatory cells clump together and form tiny lumps of cells in various organs and tissues of the body. These lumps are called granulomas (gran-yu-LO-mas). Sarcoidosis most often affects the lungs and its hilar lymph nodes but can also involve other areas of the body including the eyes, skin, sinuses, liver, kidneys, brain, and heart. Sarcoidosis varies in how active and how severe it is for each person and over time. The granulomas, when active, can cause short term and/or long term damage to the organ involved.

Sinus infection (known as sinusitis) is a major health problem. It afflicts 31 million people in the United States. Americans spend more than $1 billion each year on over-the-counter medications to treat it. Sinus infections are responsible for 16 million doctor visits and $150 million spent on prescription medications. People who have allergies, asthma, structural blockages in the nose or sinuses, or people with weak immune systems are at greater risk. A bad cold is often mistaken for a sinus infection. Many symptoms are the same, including headache or facial pain, runny nose, and nasal congestion. Unlike a cold, sinus infection symptoms may be caused by bacterial infections. It often requires treatment with antibiotics (drugs that kill the germs causing the infection).

TB is a contagious disease that is transmitted from person to person through coughing and breathing in airborne droplets that contain bacteria. TB primarily affects the lungs but can affect any part of the body. As one of the most common infections in the world, TB remains a major problem in many countries and among vulnerable populations.

Wheezing results from a narrowing or partial blockage (obstruction) somewhere in the airways. The narrowing may be widespread (as occurs in asthma, chronic obstructive pulmonary disease (COPD), and some severe allergic reactions) or only in one area (as may result from a tumor or a foreign object lodged in an airway).