Fine crackling sounds heard during inhalation caused by excess bronchial tube

Shortness of breath—what doctors call dyspnea—is the unpleasant sensation of having difficulty breathing. People experience and describe shortness of breath differently depending on the cause.

The rate and depth of breathing normally increase during exercise and at high altitudes, but the increase seldom causes discomfort. Breathing rate is also increased at rest in people with many disorders, whether of the lungs or other parts of the body. For example, people with a fever generally breathe faster.

With dyspnea, faster breathing is accompanied by the sensation of running out of air. People feel as if they cannot breathe fast enough or deeply enough. They may notice that more effort is needed to expand the chest when breathing in or to expel air when breathing out. They may also have the uncomfortable sensation that inhaling (inspiration) is urgently needed before exhaling (expiration) is completed and have various sensations often described as tightness in the chest.

The most common causes overall include

• Physical deconditioning (for example, weakening of muscles and the heart due to inactivity)

• Weight gain

• Pregnancy

The most common cause in people with a chronic lung or heart disorder is

• Worsening of their disease

However, such people may also develop another disorder. For example, people with long-standing asthma may have a heart attack, or people with chronic heart failure may develop pneumonia.

People who have lung disorders often experience dyspnea when they physically exert themselves. During exercise, the body makes more carbon dioxide and uses more oxygen. The respiratory center in the brain speeds up breathing when blood levels of oxygen are low or blood levels of carbon dioxide are high. If the heart or lungs are not functioning normally, even a little exertion can dramatically increase the breathing rate and dyspnea. Dyspnea is so unpleasant that people avoid exertion. As the lung disorder becomes more severe, dyspnea may occur even at rest.

Dyspnea may result from

• Restrictive lung disorders

• Obstructive lung disorders

In obstructive disorders (such as COPD Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease is persistent narrowing (blocking, or obstruction) of the airways occurring with emphysema, chronic obstructive bronchitis, or both disorders. Cigarette... read more

Asthma Asthma is a condition in which the airways narrow—usually reversibly—in response to certain stimuli. Coughing, wheezing, and shortness of breath that occur in response to specific triggers are... read more

People with asthma have dyspnea when they have an attack. Doctors typically advise people to keep an inhaler on hand to use during an attack. The drug in the inhaler helps open the airways.

Some people with heart failure have orthopnea, paroxysmal nocturnal dyspnea, or both. Orthopnea is shortness of breath that occurs when people lie down and is relieved by sitting up. Paroxysmal nocturnal dyspnea is a sudden, often terrifying attack of dyspnea during sleep. People awaken gasping and must sit or stand to catch their breath. This disorder is an extreme form of orthopnea and a sign of severe heart failure.

In hyperventilation syndrome, people feel that they cannot get enough air, and they breathe heavily and rapidly. This syndrome is commonly caused by anxiety rather than a physical problem. Many people who experience it are frightened, may have chest pain, and may believe they are having a heart attack. They may have a change in consciousness, usually described as feeling that events occurring around them are far away, and they may feel tingling in their hands and feet and around their mouth.

The following information can help people decide whether a doctor's evaluation is needed and help them know what to expect during the evaluation.

In people with dyspnea, the following symptoms are of particular concern:

• Shortness of breath at rest

• A decreased level of consciousness, agitation, or confusion

• Chest discomfort or the feeling the heart is pounding or racing or has skipped a beat (palpitations)

• Weight loss

• Night sweats

People who have shortness of breath at rest, chest pain, palpitations, a decreased level of consciousness, agitation, or confusion or have difficulty moving air in or out of their lungs should go to the hospital right away. Such people may need immediate testing, treatment, and sometimes admission to the hospital. Other people should call a doctor. The doctor can determine how rapidly they need to be evaluated based on the nature and severity of their symptoms, their age, and any underlying medical conditions. Typically, they should be evaluated within a few days.

Doctors ask questions to determine

• When shortness of breath started

• Whether it started abruptly or gradually

• How long the person has felt short of breath

• Whether any conditions (such as cold, exertion, exposure to allergens, or lying down) trigger it or make it worse

The person is also asked questions about past medical history (including any lung or heart disorders), a history of smoking, any family members who have had high blood pressure or high cholesterol levels, and risk factors for pulmonary embolism (such as recent hospitalization, surgery, or long-distance travel).

The physical examination focuses on the heart and lungs. Doctors listen to the lungs for congestion, wheezing, and abnormal sounds called crackles. They listen to the heart for murmurs (suggesting a heart valve disorder). Swelling of both legs suggests heart failure, but swelling of only one leg is more likely to result from a blood clot in the leg. A blood clot in the leg may break off and travel to the blood vessels in the lungs, causing pulmonary embolism.

Treatment of dyspnea is directed at the cause. People with a low blood oxygen level are given supplemental oxygen using plastic nasal prongs or a plastic mask worn over the face. In severe cases, particularly if people cannot breathe deeply or rapidly enough, breathing may be assisted by mechanical ventilation using a breathing tube inserted in the windpipe or a tight-fitting face mask.

Morphine may be given intravenously to reduce anxiety and the discomfort of dyspnea in people with various disorders, including a heart attack, pulmonary embolism, and a terminal illness.

• Shortness of breath (dyspnea) is usually caused by lung or heart disorders.

• In people with a chronic lung disorder (such as chronic obstructive pulmonary disease) or heart disorder (such as heart failure), the most common cause of dyspnea is a flare-up of the chronic disorder, but these people can also develop a new problem (such as a heart attack) that contributes to or causes dyspnea.

• People who have dyspnea at rest, a decreased level of consciousness, or confusion should go to the hospital immediately for emergency evaluation.

• To determine the severity of the problem, doctors measure oxygen levels in the blood with a sensor placed on a finger (pulse oximetry).

• Doctors evaluate people for inadequate delivery of blood and oxygen to the heart (myocardial ischemia) and for pulmonary embolism, but sometimes symptoms of these disorders are vague.

What causes crackles in the lungs?

Where are crackles heard in the lungs?

What is crackling on the chest?

Which of the respiratory sounds is heard during inspiration and expiration?