Please read the Disclaimer at the end of this page.
SHORTNESS OF BREATH OVERVIEW — Feeling short of breath can be an uncomfortable or frightening experience, especially if it has never happened to you before or occurs when doing activities that used to be easy for you. It can be caused by problems with the lungs or with the heart, or by a low blood count, but its specific cause can sometimes take a while to pinpoint. Luckily, most causes of shortness of breath can be treated quickly, if not completely eliminated, once the cause is identified.
Many cases of shortness of breath are caused by simple, short-lived problems, such as respiratory tract infections or allergies. The medical term for shortness of breath is dyspnea.
This discussion will focus on the main causes of shortness of breath and tests that might be used to figure out the source of the problem. More information about shortness of breath is available by subscription. (See "Approach to the patient with dyspnea".)
CAUSES OF SHORTNESS OF BREATH — Acute shortness of breath, which comes on suddenly, over the course of minutes or hours, usually has different causes than chronic shortness of breath, which develops over weeks or months and is persistent.
Acute shortness of breath — Acute shortness of breath usually happens along with other symptoms. The most common causes of acute shortness of breath include:
●Respiratory tract infections, such as bronchitis or pneumonia. These infections usually cause other symptoms, such as fever, cough, or coughing up sputum or mucus. (See "Patient education: Pneumonia in adults (Beyond the Basics)".)
●A severe allergic reaction (anaphylaxis), which usually also causes itching, swelling, a rash, or other symptoms. (See "Patient education: Anaphylaxis symptoms and diagnosis (Beyond the Basics)".)
●Asthma, which often causes wheezing. (See "Patient education: Asthma treatment in adolescents and adults (Beyond the Basics)" and "Patient education: Asthma treatment in children (Beyond the Basics)".)
●A blockage in the respiratory tract, which could happen after accidentally inhaling a foreign object, such as a peanut or partially chewed meat.
●A blood clot or other blockage in an artery (blood vessel) in the lungs. (See "Patient education: Pulmonary embolism (Beyond the Basics)".)
●A collapsed lung (pneumothorax). (See "Pneumothorax in adults: Epidemiology and etiology".)
●Interruptions in blood flow to the heart muscle, which might happen during a heart attack. When this is the cause of shortness of breath, there are often other symptoms, such as pain or pressure in the chest. (See "Patient education: Heart attack (Beyond the Basics)".)
●Heart failure, a condition that affects the heart's ability to pump blood throughout the body. (See "Patient education: Heart failure (Beyond the Basics)".)
●Pregnancy changes a woman's hormones and consequently the circulatory and respiratory systems, even before the woman is visibly pregnant. This type of shortness of breath may last for several weeks but when it starts, it may seem like a sudden change. This is a normal change that happens during pregnancy. (See "Maternal adaptations to pregnancy: Dyspnea and other physiologic respiratory changes".)
Chronic shortness of breath — Some of the same things that cause acute shortness of breath can also cause chronic shortness of breath. For example, asthma symptoms can come and go over months or years. Heart failure can also continue to cause shortness of breath over months or years. Most of the conditions that lead to chronic shortness of breath lead to symptoms with physical activity or exercise; when you stop the activity and rest, the symptoms typically resolve within a few minutes.
The most common causes of chronic shortness of breath include:
●Chronic obstructive pulmonary disease, a lung condition that often affects current or former smokers, includes conditions such as emphysema and chronic bronchitis. (See "Patient education: Chronic obstructive pulmonary disease (COPD) (Beyond the Basics)".)
●Interstitial lung disease, a collection of lung disorders that involve damage to or scarring of lung tissue. (See "Approach to the adult with interstitial lung disease: Clinical evaluation".)
●Cardiomyopathy, a heart condition that leads to changes in the heart's shape and size, and ability to pump blood to the rest of the body. (See "Patient education: Hypertrophic cardiomyopathy (Beyond the Basics)".)
●Deconditioning, the technical term for being out of shape. For example, if you do not exercise regularly, you may develop shortness of breath when climbing stairs or do an activity that is more intense than is common for you.
●Obesity can cause shortness of breath as extra weight in the chest and abdomen increases the work the muscles that control breathing must do.
●Pulmonary hypertension, which is high blood pressure in the arteries to your lungs. (See "Treatment and prognosis of pulmonary arterial hypertension in adults (group 1)".)
Recurrent nocturnal shortness of breath — Most patients with shortness of breath have symptoms most prominently with exertion. Occasionally, however, patients have acute symptoms at night that wake them from sleep. Possible causes include:
●Asthma. Although rarely associated with nocturnal symptoms alone, nocturnal awakenings are a sign of active airway inflammation and, if frequent, suggest a need for escalation in anti-inflammatory therapy. Nocturnal asthma can be worsened by gastroesophageal reflux (below). (See "Patient education: Asthma symptoms and diagnosis in children (Beyond the Basics)" and "Patient education: Asthma treatment in adolescents and adults (Beyond the Basics)".)
●Cardiomyopathy, valvular disease, or pulmonary hypertension. These conditions may cause fluid to pool in the lower legs during the day when you are upright (because gravity increases pressures in the veins) and then shift into the overloaded circulatory system and lungs when lying flat. (See "Patient education: Heart failure (Beyond the Basics)".)
●Gastroesophageal reflux. Individuals who have regurgitation of material from their stomach into the esophagus and throat may inhale this material into the lungs silently at night; this is called "aspiration" and can lead to nocturnal awakening, acute and chronic shortness of breath, worsening of asthma symptoms, and pneumonia. (See "Patient education: Acid reflux (gastroesophageal reflux) in babies (Beyond the Basics)" and "Patient education: Gastroesophageal reflux disease in children and adolescents (Beyond the Basics)".)
●Obstructive sleep apnea. During sleep, muscles are less active, which can cause the throat to narrow, and for some may cause intermittent blockage of the airway. This usually leads to unnoticed awakenings and unrestful sleep but can also cause episodes of awakening with choking, gasping, or smothering sensations. (See "Patient education: Sleep apnea in adults (Beyond the Basics)" and "Patient education: Sleep apnea in children (The Basics)".)
SHORTNESS OF BREATH SYMPTOMS — People describe shortness of breath in different ways. Some people say they feel "hungry for air," others say they feel as though they "cannot breathe deeply enough" or that they are working hard to breathe, and some feel a sense of "chest tightness" that impairs breathing. When you experience shortness of breath, you should pay attention to the sensations you feel and try to be as specific as possible when describing these sensations to your health care provider. If your shortness of breath varies with position, for example it comes on when you lie flat, this may be a clue to certain types of problems like the build-up of fluid in the lungs, significant weight gain, or a neurologic problem interfering with the activity of your breathing muscles.
These descriptions hold important clues about the possible cause of the problem. Here is a questionnaire your health care provider may ask you to complete to get a better sense of your symptoms (table 1).
When breathing through face coverings or masks, as have been used during the COVID-19 pandemic, some people experience shortness of breath, which is likely due to some increase in the work of breathing due to the need to pull air through the mask. During normal activity, your oxygen and carbon dioxide levels are not changed from your usual condition, however, and the sensation of working hard to breathe can be reduced by taking slow, deeper breaths rather than rapid breaths.
WHEN TO SEEK HELP — If you develop shortness of breath, particularly if it occurs or persists while at rest or is significantly worse than what you ordinarily experience (eg, it is provoked by less activity than usual), you should see a health care provider. If you have severe shortness of breath or also have chest pain or nausea, go to the closest emergency room. Shortness of breath is not a symptom to ignore.
SHORTNESS OF BREATH DIAGNOSIS — Your health care provider can learn a lot about your condition by listening to your description of the problem, and by asking about any other symptoms you may have. He or she can also learn a lot by listening to your heart and lungs with a stethoscope, and by checking your legs for swelling.
Tests — Your health care provider may also order one or more of the following tests to help diagnose the problem:
●A blood test called a hematocrit can check for anemia, a condition that affects the blood's ability to carry oxygen.
●A blood test called a BNP can indicate if you have fluid buildup in your lungs.
●A chest X-ray to look for pneumonia, or lung inflammation or scarring.
●An EKG is a test of your heart muscle that looks for signs of a heart attack.
●A test called spirometry to measure the amount of air your lungs can hold and how effectively your lungs can empty and fill with air. This test can also indicate if you have asthma or emphysema.
●A test called oximetry to measure the amount of oxygen in your blood.
SHORTNESS OF BREATH TREATMENT — The treatment for your shortness of breath will depend a lot on what is causing it. Shortness of breath caused by asthma, for example, will need one type of treatment, whereas shortness of breath caused by heart failure will need quite another.
WHERE TO GET MORE INFORMATION — Your health care provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Shortness of breath (The Basics)
Patient education: Pneumothorax (collapsed lung) (The Basics)
Patient education: Pleural effusion (The Basics)
Patient education: Sinus node dysfunction (The Basics)
Patient education: Idiopathic pulmonary fibrosis (The Basics)
Patient education: Atelectasis (The Basics)
Patient education: Allergic bronchopulmonary aspergillosis (The Basics)
Patient education: Pleural mesothelioma (The Basics)
Patient education: Heart failure with preserved ejection fraction (The Basics)
Patient education: Heart failure with reduced ejection fraction (The Basics)
Patient education: Interstitial lung disease (The Basics)
Patient education: Lung transplant (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient education: Pneumonia in adults (Beyond the Basics)
Patient education: Anaphylaxis symptoms and diagnosis (Beyond the Basics)
Patient education: Asthma treatment in adolescents and adults (Beyond the Basics)
Patient education: Asthma treatment in children (Beyond the Basics)
Patient education: Pulmonary embolism (Beyond the Basics)
Patient education: Heart attack (Beyond the Basics)
Patient education: Heart failure (Beyond the Basics)
Patient education: Chronic obstructive pulmonary disease (COPD) (Beyond the Basics)
Patient education: Hypertrophic cardiomyopathy (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Approach to the patient with dyspnea
Maternal adaptations to pregnancy: Dyspnea and other physiologic respiratory changes
Approach to the adult with dyspnea in the emergency department
Physiology of dyspnea
Pneumothorax in adults: Epidemiology and etiology
Approach to the adult with interstitial lung disease: Clinical evaluation
Treatment and prognosis of pulmonary arterial hypertension in adults (group 1)
The following organizations also provide reliable health information.
●National Library of Medicine
●American College of Chest Physicians
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟