Shortness of breath (dyspnea)
Shortness of breath, or dyspnea, is an uncomfortable feeling of not getting enough air. Many causes are harmless and easily corrected; however, shortness of breath can be a symptom of a serious medical condition. For some individuals, a sense of breathlessness may occur with only mild exercise (for example, climbing stairs) without an indication of the presence of a specific disorder. Others may have advanced lung disease and difficulty exchanging air but may never feel a
sensation of shortness of breath. In some circumstances, a small degree of breathing difficulty may be normal. Severe nasal congestion is one example. Strenuous exercise, especially when a person does not exercise regularly, is another. In many situations, however, difficulty breathing represents the presence of significant disease and should be evaluated by a health care provider immediately.
Shortness of breath has many different causes. Obstruction of the air passages of the nose, mouth, or throat may lead to difficulty breathing. Heart disease can cause breathlessness if the heart is unable to pump enough blood to supply oxygen to the body. If the brain, muscles, or other body organs do not receive enough oxygen, a sense of breathlessness may occur. Sometimes emotional distress, such as anxiety, can lead to difficulty breathing.
Acute dyspnea with sudden onset is a frequent cause of emergency room visits. Most cases of acute dyspnea involve pulmonary (lung and breathing) disorders, cardiovascular disease, or chest trauma. Pulmonary disorders that can cause dyspnea include airway obstruction by a foreign object, swelling due to infection, or anaphylactic shock; acute pneumonia; hemorrhage from the lungs; or severe bronchospasms associated with asthma. Acute dyspnea can be caused by disturbances of the heart rhythm, failure of the left ventricle, mitral valve (a heart valve) dysfunction, or an embolus (a clump of tissue, fat, or gas) that is blocking the pulmonary circulation. Most pulmonary emboli (blood clots) originate in the deep veins of the lower legs and eventually migrate to the pulmonary artery. Chest injuries, both closed injuries and penetrating wounds, can cause pneumothorax (the presence of air inside the chest cavity), bruises, or fractured ribs. Pain from these injuries results in dyspnea. The impact of the driver's chest against the steering wheel in auto accidents is a frequent cause of closed chest injuries.
Chronic dyspnea can be caused by asthma, chronic obstructive pulmonary disease (COPD), bronchitis, emphysema, inflammation of the lungs, pulmonary hypertension, tumors, or disorders of the vocal cords. Disorders of the left side of the heart or inadequate supply of blood to the heart muscle can cause dyspnea. In some cases a tumor in the heart or inflammation of the membrane surrounding the heart may cause dyspnea. Neuromuscular disorders cause dyspnea from progressive deterioration of the patient's chest muscles. They include muscular dystrophy, myasthenia gravis, and amyotrophic lateral sclerosis. Patients who are severely anemic may develop dyspnea if they exercise vigorously. Hyperthyroidism or hypothyroidism may cause shortness of breath, and so may gastroesophageal reflux disease (GERD). Both chronic anxiety disorders, and a low level of physical fitness can also cause episodes of dyspnea. Deformities of the chest or obesity can cause dyspnea by limiting the movement of the chest wall and the ability of the lungs to fill completely.
Diagnosis of the cause of shortness of breath begins with a history and physical exam. This may be all that is needed. But usually more tests have to be done, and they are based on the suspected condition. Blood tests and chest x-rays are commonly performed. Other tests may include an ECG, or electrocardiogram, which measures the electrical activity in the heart. An ECG can often help diagnose heart conditions that may be causing shortness of breath. Other tests may be needed in some cases, such as special x-rays or breathing tests.
Breathing difficulty, whether sudden or long term, should always be taken seriously. Though many causes are harmless and are easily corrected, any difficulty breathing requires a thorough medical evaluation. In standard medical therapy treatment for dyspnea is directed toward both alleviating dyspnea and prolonging the patient's life. This is entirely appropriate for many patients. An example would be the administration of ACE (angiotensin converting enzyme) inhibitors for congestive heart failure. These medications both relieve dyspnea by decreasing pulmonary edema through afterload reduction and can prolong life. ACE inhibitors may also be used in patients with congestive heart failure whose primary treatment goal is comfort. Oxygen at 5 L/minute has been shown to decrease the intensity of dyspnea in hypoxic individuals with advanced cancer. Opioids such as morphine are commonly used to manage dyspnea in the terminal phase and are highly effective.