Short of breath? Coughing? Chest pain? Johns Hopkins doctors explain why you should take your symptoms seriously.

Many lung disorders produce similar symptoms, but the severity and duration of these symptoms can vary considerably from disease to disease. The lung disorders can be acute (short and relatively severe) or chronic (persisting over a long time).

Chronic lung conditions may wax and wane in severity and can worsen quickly and markedly if another problem, such as a lung infection, occurs. Some people, however, have only mild symptoms or none at all. In these individuals, the lung disorder may be detected on a chest x-ray or by a test to check lung function.

• Shortness of breath. Shortness of breath can dramatically compromise quality of life. The underlying cause of shortness of breath is usually a mechanical problem in the lungs or diaphragm (the large, dome-shaped muscle located at the base of the lungs). Examples of mechanical problems are airway obstruction (as occurs in asthma, COPD, and some lung cancers); increased stiffness of the lungs (as in interstitial lung disease, pneumonia, and heart failure); severe spine and rib cage abnormalities; and obesity.

  If left untreated, shortness of breath can lead to fatigue and weakness that may profoundly limit activities. In turn, weakness related to being out of shape or musculoskeletal disease, such as severe curvature of the spine, may aggravate shortness of breath.

• Coughing. Coughing up phlegm, infectious germs, and foreign substances is one of the ways in which the lungs protect themselves. Severe coughing, however, may signal lung disease. Obstructive diseases of the lungs (asthma and COPD) and lung cancer often cause a person to cough up phlegm, which, if yellow or green, may signal an infection. Coughing up blood is a critical sign, especially in a current or former cigarette smoker. It may suggest a potentially life-threatening disease, such as lung cancer or pulmonary embolism, although it can also be a sign of a less serious lung problem such as bronchitis.
• Noisy breathing. Noisy breathing is an especially common sign of lung disease. Abnormal sounds range from a high-pitched crowing during inhalation to continuous musical sounds during exhalation (wheezing, which occurs with asthma and some other disorders). The maxim “all that wheezes is not asthma” underscores the fact that many health conditions, including diseases of the larynx, heart failure, pulmonary embolism, and COPD, can cause wheezing. Repetitive loud snoring during sleep, interrupted by periods of silence in which there's no air flow, is a major sign of sleep apnea.

• Chest pain. Chest pain or other discomfort has numerous causes, and determining whether the cause is a heart, esophageal, or lung disease is often challenging. Pain on one side of the chest that worsens with deep breathing, coughing, or laughing suggests pleurisy, an inflammation of the pleura (the membrane around the surface of the lungs and the inner chest wall). Pleurisy may be caused by an infection, such as pneumonia; pulmonary embolism; cancer; or a systemic (affecting the entire body) inflammatory disease such as systemic lupus erythematosus. Alternatively, pain that worsens on inhalation may be due to a chest wall injury such as a broken rib.