Many conditions can cause dyspnea.

Dyspnea is the feeling of difficult or uncomfortable breathing or of not getting enough air. It also may be called shortness of breath, breathlessness, or air hunger. In cancer patients, causes of dyspnea include the following:

• Effects related to the tumor:
  • The tumor blocks the airways in the chest and lung or the vein that carries blood through the chest to the heart.
  • The tumor causes extra fluid to build up in the space between the thin layer of tissue covering the lung and the thin layer of tissue covering the chest wall (pleural effusion), between the sac that covers the heart and the heart (pericardial effusion), or in the abdominal cavity (ascites).
  • Carcinomatous lymphangitis (inflammation of the lymph vessels).
  • Chest infections. Some cancer treatments may increase the risk of an infection, such as pneumonia.
  • Blood clots or tumor cells that break loose and block a blood vessel in the lungs.
  • Paralysis of part of the diaphragm (a muscle used for breathing).
  • Breathing muscles get weaker.

• Effects related to treatment:
  • Damage to the lung caused by radiation therapy or chemotherapy.
  • Weakened heart muscle caused by chemotherapy.

• Conditions that are not related to cancer:
  • Chronic obstructive pulmonary disease (COPD), such as chronic bronchitis or emphysema.
  • Bronchospasm. The muscles in the airways contract and cause spasms.
  • A weak diaphragm.
  • Congestive heart failure.
  • Anemia.

• Conditions with no known physical cause, such as anxiety.

A diagnosis of the cause of dyspnea or coughing helps to plan treatment.

Diagnostic tests and procedures include the following:

• Physical exam and history for dyspnea: An exam of the body to check general signs of health, including checking for signs of dyspnea, such as breathing fast or using the neck or chest muscles to breathe. A history of your health habits and past illnesses and treatments will also be taken. Your doctor will also ask about when the dyspnea occurs, what it feels like, other symptoms that happen at the same time as the dyspnea, and anything that makes it better or worse.

• Functional assessment: An exam to check for how the dyspnea affects your ability to perform activities of daily living such as eating, bathing, or climbing stairs.

• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.

• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

• Complete blood count: A procedure in which a sample of blood is taken and checked for the following:
  • The number of red blood cells, white blood cells, and platelets.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made of red blood cells.

• Oxygen saturation test: A procedure to check for the amount of oxygen being carried by the red blood cells. A lower than normal amount of oxygen may be a sign of lung disease or other health problems. One method uses a device clipped to the finger. The device senses the amount of oxygen in the blood flowing through the small blood vessels in the finger. Another method uses a sample of blood taken from an artery, usually in the wrist, that is tested for the amount of oxygen.

• Maximum inspiratory pressure (MIP) test: The MIP is the highest pressure that can be reached in the lungs when you take a deep breath. When you breathe through a device called a manometer, the device measures the pressure. The information is sent to a computer. The pressure level shows how strong the breathing muscles are.

It may be possible to treat the cause of dyspnea.

Treatment may include the following:

• Radiation therapy: Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a machine outside the body to send radiation toward the cancer.

• Hormone therapy: Hormone therapy is a cancer treatment that removes hormones or blocks their action and stops cancer cells from growing. Hormones are substances made by glands in the body and circulated in the bloodstream. Some hormones can cause certain cancers to grow. If tests show that the cancer cells have places where hormones can attach (receptors), drugs, surgery, or radiation therapy is used to reduce the production of hormones or block them from working.

• Chemotherapy: Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.

• Laser therapy for tumors inside large airways: Use of a laser beam (a narrow beam of intense light) as a knife to remove the tumor.

• Cauterization of tumors inside large airways: Use of a hot instrument, an electric current, or a caustic substance to destroy the tumor.

• Procedures to remove fluid that has built up around the lungs (malignant pleural effusion), around the heart (malignant pericardial effusion), or in the abdominal cavity. (See the sections on controlling the symptoms of malignant pleural effusion and malignant pericardial effusion for more information.)

• Stent placement: Surgery to place a stent (thin tube) in an airway to keep it open. This may be done if a large airway is blocked by a tumor that is pressing on it from the outside.

• Medicine:
  • Steroid drugs for inflamed or swollen lymph vessels in the lungs.
  • Antibiotics for chest infections. These may be used with chest physical therapy.
  • Anticoagulants for blood clots that are blocking blood vessels in the lungs.
  • Bronchodilators that are inhaled to open up the bronchioles (small airways) in the lungs.
  • Diuretics and other drugs for heart failure.

• Blood transfusions for anemia.

Treatment of dyspnea depends on the cause of it.

The treatment of dyspnea depends on its cause, as follows:

Treatment may be to control the symptoms of dyspnea.

Treatment to control the symptoms of dyspnea may include the following:

• Oxygen therapy: Patients who cannot get enough oxygen from the air may be given extra oxygen to inhale from a tank. Devices that concentrate oxygen already in the air may also be prescribed.

• Medicines: Opioids, such as morphine, may lessen physical and mental distress and exhaustion and the feeling that the patient cannot take enough air in. Other drugs may be used to treat dyspnea that is related to panic disorder or severe anxiety.

• Supportive care:
  • Breathing methods, such as breathing with the lips pursed (almost closed).
  • Using a fan to blow cold air across the cheek.
  • Meditation.
  • Relaxation training.
  • Biofeedback.
  • Talk therapy to relieve anxiety.

Chronic coughing may cause dyspnea.

The causes of chronic coughing are almost the same as the causes of dyspnea. A chronic cough may cause pain, trouble sleeping, dyspnea, and fatigue.

Medicines used to control coughing include the following:

• Cough-suppressing medicine, including opioids.
• Medicine that breaks down mucus.
• An inhaled drug for chronic coughing related to lung cancer.

The cause of the coughing is also treated.