Shortness of breath (SOB), also medically known as dyspnea (in
AmE #REDIRECT AME
{{redirect category shell, {{R from other capitalisation{{R from ambiguous page ...
) or dyspnoea (in
BrE
British English (BrE, en-GB, or BE) is, according to Oxford Dictionaries, "English as used in Great Britain, as distinct from that used elsewhere". More narrowly, it can refer specifically to the English language in England, or, more broadly, ...
), is an uncomfortable feeling of not being able to
breathe well enough. The
American Thoracic Society The American Thoracic Society (ATS) is a nonprofit organization focused on improving care for pulmonary diseases, critical illnesses and sleep-related breathing disorders. It was established in 1905 as the
American Sanatorium Association, and ...
defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of its distinct sensations, the degree of distress and discomfort involved, and its burden or impact on the patient's
activities of daily living
Activity may refer to:
* Action (philosophy), in general
* Human activity: human behavior, in sociology behavior may refer to all basic human actions, economics may study human economic activities and along with cybernetics and psychology may s ...
. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen).
The
tripod position is often assumed to be a sign.
Dyspnea is a normal
symptom of heavy physical
exertion
Exertion is the physical or perceived use of energy.Newton's Third Law, Elert, Glenn. “Forces.” ''Viscosity – The Physics Hypertextbook'', physics.info/newton-first/. Exertion traditionally connotes a strenuous or costly ''effort'', resulting ...
but becomes
pathological
Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in th ...
if it occurs in unexpected situations,
[ when resting or during light exertion. In 85% of cases it is due to ]asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
, pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...
, cardiac ischemia
Coronary ischemia, myocardial ischemia, or cardiac ischemia,Potochny, Evy. "Cardiac Ischemia Symptoms." LiveStrong. Demand Media, 9 March 2010. Web. 6 Nov. 2010. is a medical term for a reduced blood flow in the coronary circulation through the ...
, interstitial lung disease
Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium (the tissue and space around the alveoli (air sacs)) of the lungs. It concerns alveolar epithelium, pu ...
, congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
, chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...
, or psychogenic
A psychogenic effect is one that originates from the brain instead of other physical organs (i.e. the cause is psychological rather than physiological) and may refer to:
* Psychogenic pain
*Psychogenic disease
* Psychogenic amnesia
*Psychogenic co ...
causes,[ such as ]panic disorder
Panic disorder is a mental and behavioral disorder, specifically an anxiety disorder characterized by reoccurring unexpected panic attacks. Panic attacks are sudden periods of intense fear that may include palpitations, sweating, shaking, short ...
and anxiety
Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
. The best treatment to relieve or even remove shortness of breath typically depends on the underlying cause.[
]
Definition
Dyspnea, in medical terms, is "shortness of breath".
The American Thoracic Society The American Thoracic Society (ATS) is a nonprofit organization focused on improving care for pulmonary diseases, critical illnesses and sleep-related breathing disorders. It was established in 1905 as the
American Sanatorium Association, and ...
defines dyspnea as: "A subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity." Other definitions also describe it as "difficulty in breathing", "disordered or inadequate breathing", "uncomfortable awareness of breathing",[ and as the experience of "breathlessness" (which may be either acute or chronic).]
Differential diagnosis
While shortness of breath is generally caused by disorders of the cardiac
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...
or respiratory system
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies ...
, others such as the neurological
Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal c ...
, musculoskeletal
The human musculoskeletal system (also known as the human locomotor system, and previously the activity system) is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system prov ...
, endocrine, hematologic
Hematology ( always spelled haematology in British English) is the branch of medicine concerned with the study of the cause, prognosis, treatment, and prevention of diseases related to blood. It involves treating diseases that affect the produc ...
, and psychiatric systems may be the cause. DiagnosisPro, an online medical expert system, listed 497 distinct causes in October 2010. The most common cardiovascular causes are acute myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may t ...
and congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
while common pulmonary causes include chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...
, asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
, pneumothorax
A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath. In a minority of cases, a one-way valve i ...
, pulmonary edema and pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...
.[ On a pathophysiological basis the causes can be divided into: (1) an increased awareness of normal breathing such as during an anxiety attack, (2) an increase in the work of breathing and (3) an abnormality in the ventilatory or respiratory system.]
The tempo of onset and the duration of dyspnea are useful in knowing the etiology of dyspnea. Acute shortness of breath is usually connected with sudden physiological changes, such as laryngeal edema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area ma ...
, bronchospasm
Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes di ...
, myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
, pulmonary embolism
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream ( embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathin ...
, or pneumothorax
A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath. In a minority of cases, a one-way valve i ...
. Patients with COPD and idiopathic pulmonary fibrosis (IPF) have a mild onset and gradual progression of dyspnea on exertion, punctuated by acute exacerbations of shortness of breath. In contrast, most asthmatics do not have daily symptoms, but have intermittent episodes of dyspnea, cough, and chest tightness that are usually associated with specific triggers, such as an upper respiratory tract infection or exposure to allergens.
Acute coronary syndrome
Acute coronary syndrome frequently presents with retrosternal chest discomfort
Chest pain is pain or discomfort in the chest, typically the front of the chest. It may be described as sharp, dull, pressure, heaviness or squeezing. Associated symptoms may include pain in the shoulder, arm, upper abdomen, or jaw, along with ...
and difficulty catching the breath.[ It however may atypically present with shortness of breath alone.][ Risk factors include old age, smoking, hypertension, ]hyperlipidemia
Hyperlipidemia is abnormally elevated levels of any or all lipids (fats, cholesterol, or triglycerides) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also used as an umbre ...
, and diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
.[ An electrocardiogram and cardiac enzymes are important both for diagnosis and directing treatment.][ Treatment involves measures to decrease the oxygen requirement of the heart and efforts to increase blood flow.][
]
COVID-19
People that have been infected by COVID-19
Coronavirus disease 2019 (COVID-19) is a contagious disease caused by a virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was identified in Wuhan, China, in December 2019. The disease quickly ...
may have symptoms such as a fever, dry cough, loss of smell and taste, and in moderate to severe cases, shortness of breath.
Congestive heart failure
Congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
frequently presents with shortness of breath with exertion, orthopnea
Orthopnea or orthopnoea is shortness of breath (dyspnea) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. It is commonly seen as a late manifestation of heart failure, resulting from fluid ...
, and paroxysmal nocturnal dyspnea
Paroxysmal nocturnal dyspnea or paroxysmal nocturnal dyspnoea (PND) is an attack of severe shortness of breath and coughing that generally occurs at night. It usually awakens the person from sleep, and may be quite frightening. PND, as well as simp ...
.[ It affects between 1–2% of the general United States population and occurs in 10% of those over 65 years old.][ Risk factors for acute decompensation include high dietary ]salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...
intake, medication noncompliance, cardiac ischemia, abnormal heart rhythms, kidney failure
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...
, pulmonary emboli, hypertension, and infections.[ Treatment efforts are directed towards decreasing lung congestion.][
]
Chronic obstructive pulmonary disease
People with chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...
(COPD), most commonly emphysema or chronic bronchitis
Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. ...
, frequently have chronic shortness of breath and a chronic productive cough.[ An acute exacerbation presents with increased shortness of breath and sputum production.][ ]COPD
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...
is a risk factor for pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...
; thus this condition should be ruled out.[ In an acute exacerbation treatment is with a combination of ]anticholinergics
Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system.
These agents inhibit the parasympathetic nervous sy ...
, beta2-adrenoceptor agonists, steroids and possibly positive pressure ventilation
Modes of mechanical ventilation are one of the most important aspects of the usage of mechanical ventilation. The mode refers to the method of inspiratory support. In general, mode selection is based on clinician familiarity and institutional pref ...
.[
]
Asthma
Asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
is the most common reason for presenting to the emergency room with shortness of breath.[ It is the most common lung disease in both developing and developed countries affecting about 5% of the population.][ Other symptoms include ]wheezing
A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...
, tightness in the chest, and a non productive cough.[
Inhaled corticosteroids are the preferred treatment for children, however these drugs can reduce the growth rate. Acute symptoms are treated with short-acting bronchodilators.
]
Pneumothorax
Pneumothorax
A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath. In a minority of cases, a one-way valve i ...
presents typically with pleuritic chest pain of acute onset and shortness of breath not improved with oxygen.[ Physical findings may include absent breath sounds on one side of the chest, ]jugular venous distension
The jugular venous pressure (JVP, sometimes referred to as ''jugular venous pulse'') is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different for ...
, and tracheal deviation.[
]
Pneumonia
The symptoms of pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...
are fever
Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...
, productive cough
A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phas ...
, shortness of breath, and pleuritic chest pain.[ Inspiratory ]crackles
Crackles are the clicking, rattling, or crackling noises that may be made by one or both lungs of a human with a respiratory disease during inhalation. They are usually heard only with a stethoscope ("on auscultation"). Pulmonary crackles are a ...
may be heard on exam.[ A chest x-ray can be useful to differentiate pneumonia from ]congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
.[ As the cause is usually a bacterial infection, ]antibiotics
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...
are typically used for treatment.[
]
Pulmonary embolism
Pulmonary embolism
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream ( embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathin ...
classically presents with an acute onset of shortness of breath.[ Other presenting symptoms include pleuritic chest pain, cough, ]hemoptysis
Hemoptysis is the coughing up of blood or blood-stained mucus from the bronchi, larynx, trachea, or lungs. In other words, it is the airway bleeding. This can occur with lung cancer, infections such as tuberculosis, bronchitis, or pneumonia, a ...
, and fever
Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...
.[ Risk factors include ]deep vein thrombosis
Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...
, recent surgery, cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
, and previous thromboembolism
Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...
.[ It must always be considered in those with acute onset of shortness of breath owing to its high risk of mortality.][ Diagnosis, however, may be difficult][ and Wells Score is often used to assess the clinical probability. Treatment, depending on severity of symptoms, typically starts with ]anticoagulants
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where they ...
; the presence of ominous signs (low blood pressure) may warrant the use of thrombolytic drugs.[
]
Anemia
Anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
that develops gradually usually presents with exertional dyspnea, fatigue, weakness, and tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ( ...
.[ It may lead to heart failure.][ Anaemia is often a cause of dyspnea. Menstruation, particularly if excessive, can contribute to anaemia and to consequential dyspnea in women. Headaches are also a symptom of dyspnea in patients with anaemia. Some patients report a numb sensation in their head, and others have reported blurred vision caused by hypotension behind the eye due to a lack of oxygen and pressure; these patients have also reported severe head pains, many of which lead to permanent brain damage. Symptoms can include loss of concentration, focus, fatigue, language faculty impairment and memory loss.
]
Cancer
Shortness of breath is common in people with cancer and may be caused by numerous different factors. In people with advanced cancer, acute shortness of periods of time with severe shortness of breath may occur, along with a more continuous feeling of breathlessness.
Other
Other important or common causes of shortness of breath include cardiac tamponade
Cardiac tamponade, also known as pericardial tamponade (), is the buildup of fluid in the pericardium (the sac around the heart), resulting in compression of the heart. Onset may be rapid or gradual. Symptoms typically include those of obstructi ...
, anaphylaxis
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the foll ...
, interstitial lung disease
Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium (the tissue and space around the alveoli (air sacs)) of the lungs. It concerns alveolar epithelium, pu ...
, panic attack
Panic attacks are sudden periods of intense fear and discomfort that may include palpitations, sweating, chest pain or chest discomfort, shortness of breath, trembling, dizziness, numbness, confusion, or a feeling of impending doom or of losing ...
s, and pulmonary hypertension. Also, around 2/3 of women experience shortness of breath as a part of a normal pregnancy
Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occur ...
.[
Cardiac tamponade presents with dyspnea, tachycardia, elevated jugular venous pressure, and ]pulsus paradoxus
Pulsus paradoxus, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is less than 10 mmHg. When the drop ...
.[ The gold standard for diagnosis is ]ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
.[
Anaphylaxis typically begins over a few minutes in a person with a previous history of the same.][ Other symptoms include ]urticaria
Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-last ...
, throat swelling, and gastrointestinal upset.[ The primary treatment is epinephrine.][
Interstitial lung disease presents with gradual onset of shortness of breath typically with a history of a predisposing environmental exposure.][ Shortness of breath is often the only symptom in those with ]tachydysrhythmias
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (su ...
.[
Panic attacks typically present with hyperventilation, sweating, and ]numbness
Hypoesthesia or numbness is a common side effect of various medical conditions that manifests as a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is generally referred to as num ...
.[ They are however a diagnosis of exclusion.][
Neurological conditions such as spinal cord injury, phrenic nerve injuries, ]Guillain–Barré syndrome
Guillain–Barré syndrome (GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. Typically, both sides of the body are involved, and the initial symptoms are changes in sensation or pain oft ...
, amyotrophic lateral sclerosis, multiple sclerosis and muscular dystrophy can all cause an individual to experience shortness of breath. Shortness of breath can also occur as a result of vocal cord dysfunction
Vocal cord dysfunction (VCD) is a pathology affecting the vocal folds (commonly referred to as the vocal cords) characterized by full or partial vocal fold closure causing difficulty and distress during respiration, especially during inhalation.
...
(VCD).
Sarcoidosis
Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly a ...
is an inflammatory disease of unknown etiology that generally presents with dry cough, fatigue, and shortness of breath, although multiple organ systems may be affected, with involvement of sites such as the eyes, the skin and the joints.
Pathophysiology
Different physiological pathways may lead to shortness of breath including via ASIC chemoreceptor
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
s, mechanoreceptors, and lung receptors.
It is thought that three main components contribute to dyspnea: afferent signals, efferent signals, and central information processing. It is believed the central processing in the brain compares the afferent and efferent signals; and dyspnea results when a "mismatch" occurs between the two: such as when the need for ventilation (afferent signaling) is not being met by physical breathing (efferent signaling).
Afferent signals are sensory neuronal signals that ascend to the brain. Afferent neurons significant in dyspnea arise from a large number of sources including the carotid bodies, medulla
Medulla or Medullary may refer to:
Science
* Medulla oblongata, a part of the brain stem
* Renal medulla, a part of the kidney
* Adrenal medulla, a part of the adrenal gland
* Medulla of ovary, a stroma in the center of the ovary
* Medulla of t ...
, lungs
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side ...
, and chest wall. Chemoreceptors in the carotid bodies and medulla supply information regarding the blood gas levels of O2, CO2 and H+. In the lungs, juxtacapillary (J) receptors are sensitive to pulmonary interstitial edema, while stretch receptors signal bronchoconstriction. Muscle spindles
Muscle spindles are stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle. They convey length information to the central nervous system via afferent nerve fibers. This information can be ...
in the chest wall signal the stretch and tension of the respiratory muscles. Thus, poor ventilation leading to hypercapnia
Hypercapnia (from the Greek ''hyper'' = "above" or "too much" and ''kapnos'' = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous pro ...
, left heart failure leading to interstitial edema (impairing gas exchange), asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
causing bronchoconstriction (limiting airflow) and muscle fatigue leading to ineffective respiratory muscle action could all contribute to a feeling of dyspnea.
Efferent signals are the motor neuronal signals descending to the respiratory muscles
The muscles of respiration are the muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity. The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during q ...
. The most important respiratory muscle is the diaphragm. Other respiratory muscles include the external and internal intercostal muscles
Intercostal muscles are many different groups of muscles that run between the ribs, and help form and move the chest wall. The intercostal muscles are mainly involved in the mechanical aspect of breathing by helping expand and shrink the size of ...
, the abdominal muscles and the accessory breathing muscles.
As the brain receives its plentiful supply of afferent information relating to ventilation, it is able to compare it to the current level of respiration as determined by the efferent signals. If the level of respiration is inappropriate for the body's status then dyspnea might occur. There is also a psychological component to dyspnea, as some people may become aware of their breathing in such circumstances but not experience the typical distress of dyspnea.
Diagnosis
The initial approach to evaluation begins by assessment of the airway, breathing, and circulation followed by a medical history
The medical history, case history, or anamnesis (from Greek: ἀνά, ''aná'', "open", and μνήσις, ''mnesis'', "memory") of a patient is information gained by a physician by asking specific questions, either to the patient or to other peo ...
and physical examination
In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the pati ...
.[ Signs and symptoms that represent significant severity include ]hypotension
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...
, hypoxemia
Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia has many causes, and often causes hypoxia as the blood is not supplying enough oxygen to the tissues of the bod ...
, tracheal deviation, altered mental status, unstable dysrhythmia, stridor, intercostal indrawing, cyanosis, tripod positioning, pronounced use of accessory muscles ( sternocleidomastoid, scalenes) and absent breath sounds.[
A number of scales may be used to quantify the degree of shortness of breath.] It may be subjectively rated on a scale from 1 to 10 with descriptors associated with the number (The Modified Borg Scale
The Borg are an alien group that appear as recurring antagonists in the ''Star Trek'' fictional universe. The Borg are Cyborg, cybernetic organisms (cyborgs) linked in a Group mind (science fiction), hive mind called "the Collective". The Borg ...
).[ The ]MRC
MRC may refer to
Government
* Medical Research Council (United Kingdom)
* Medical Reserve Corps, a US network of volunteer organizations
* Municipalité régionale de comté (regional county municipality), Quebec, Canada
* Military Revolutionar ...
breathlessness scale suggests five grades of dyspnea based on the circumstances and severity in which it arises.
Blood tests
A number of labs may be helpful in determining the cause of shortness of breath. D-dimer
D-dimer (or D dimer) is a fibrin degradation product (or FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is so named because it contains two D fragments of the fibrin protein joined by a cros ...
, while useful to rule out a pulmonary embolism in those who are at low risk, is not of much value if it is positive, as it may be positive in a number of conditions that lead to shortness of breath.[ A low level of ]brain natriuretic peptide
Brain natriuretic peptide 32 (BNP), also known as B-type natriuretic peptide, is a hormone secreted by cardiomyocytes in the heart ventricles in response to stretching caused by increased ventricular blood volume. Along with NT-proBNP, BNP is one ...
is useful in ruling out congestive heart failure; however, a high level, while supportive of the diagnosis, could also be due to advanced age, kidney failure
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...
, acute coronary syndrome, or a large pulmonary embolism.[
]
Imaging
A chest x-ray is useful to confirm or rule out a pneumothorax, pulmonary edema
Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due t ...
, or pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...
.[ Spiral computed tomography with intravenous ]radiocontrast
Radiocontrast agents are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography ( contrast CT), projectional radiography, and fluoroscopy. Radiocontrast agents are typically i ...
is the imaging study of choice to evaluate for pulmonary embolism.[
]
Treatment
The primary treatment of shortness of breath is directed at its underlying cause.[ Extra supplemental ]oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
is effective in those with hypoxia; however, this has no effect in those with normal blood oxygen saturations.[
]
Physiotherapy
Individuals can benefit from a variety of physical therapy interventions. Persons with neurological/neuromuscular abnormalities may have breathing difficulties due to weak or paralyzed intercostal, abdominal and/or other muscles needed for ventilation
Ventilation may refer to:
* Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation
** Mechanical ventilation, in medicine, using artificial methods to assist breathing
*** Ventilator, a m ...
. Some physical therapy interventions for this population include active assisted cough
A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ph ...
techniques, volume augmentation such as breath stacking, education about body position and ventilation patterns and movement strategies to facilitate breathing. Pulmonary rehabilitation
Pulmonary rehabilitation, also known as respiratory rehabilitation, is an important part of the management and health maintenance of people with chronic respiratory disease who remain symptomatic or continue to have decreased function despite stand ...
may alleviate symptoms in some people, such as those with COPD, but will not cure the underlying disease. Fan therapy to the face has been shown to relieve shortness of breath in patients with a variety of advanced illnesses including cancer. The mechanism of action is thought to be stimulation of the trigeminal nerve.
Palliative medicine
Systemic immediate release opioids are beneficial in emergently reducing the symptom severity of shortness of breath due to both cancer and non cancer causes;[ long-acting/sustained-release opioids are also used to prevent/continue treatment of dyspnea in palliative setting. There is a lack of evidence to recommend ]midazolam
Midazolam, sold under the brand name Versed among others, is a benzodiazepine medication used for anesthesia and procedural sedation, and to treat severe agitation. It works by inducing sleepiness, decreasing anxiety, and causing a loss of ...
, nebulised opioids, the use of gas mixtures, or cognitive-behavioral therapy
Cognitive behavioral therapy (CBT) is a psycho-social intervention that aims to reduce symptoms of various mental health conditions, primarily depression and anxiety disorders. CBT focuses on challenging and changing cognitive distortions (suc ...
yet.
Non-pharmacological techniques
Non-pharmacological interventions provide key tools for the management of breathlessness. Potentially beneficial approaches include active management of psychosocial
The psychosocial approach looks at individuals in the context of the combined influence that psychological factors and the surrounding social environment have on their physical and mental wellness and their ability to function. This approach is ...
issues (anxiety
Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
, depression, etc.), and implementation of self-management strategies, such as physical and mental relaxation technique
A relaxation technique (also known as relaxation training) is any method, process, procedure, or activity that helps a person to relax; to attain a state of increased calmness; or otherwise reduce levels of pain, anxiety, stress or anger. Rela ...
s, pacing techniques, energy conservation techniques, learning exercises to control breathing, and education
Education is a purposeful activity directed at achieving certain aims, such as transmitting knowledge or fostering skills and character traits. These aims may include the development of understanding, rationality, kindness, and honesty ...
. The use of a fan may possibly be beneficial. Cognitive behavioural therapy may also be helpful.
Pharmacological treatment
For people with severe, chronic, or uncontrollable breathlessness, non-pharmacological approaches to treating breathlessness may be combined with medication. For people who have cancer that is causing the breathlessness, medications that have been suggested include opioids, benzodiazepines, oxygen, and steroids. Results of recent systematic reviews and meta-analyses found opioids were not necessarily associated with more effectiveness in treatment for patients with advanced cancer.
Ensuring that the balance between side effects and adverse effects from medications and potential improvements from medications needs to be carefully considered before prescribing medication. The use of systematic corticosteriods in palliative care for people with cancer is common, however the effectiveness and potential adverse effects of this approach in adults with cancer has not been well studied.
Epidemiology
Shortness of breath is the primary reason 3.5% of people present to the emergency department in the United States. Of these individuals, approximately 51% are admitted to the hospital and 13% are dead within a year. Some studies have suggested that up to 27% of hospitalized people develop dyspnea,[Murray and Nadel's Textbook of Respiratory Medicine, 4th Ed. Robert J. Mason, John F. Murray, Jay A. Nadel, 2005, Elsevier] while in dying patients 75% will experience it.[Harrison's Principles of Internal Medicine (Kasper DL, Fauci AS, Longo DL, et al. (eds)) (16th ed.). New York: McGraw-Hill.] Acute shortness of breath is the most common reason people requiring palliative care visit an emergency department. Up to 70% of adults with advanced cancer also experience dyspnoea.
Etymology and pronunciation
English ''dyspnea'' comes from Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''dyspnoea'', from Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
''dyspnoia'', from ''dyspnoos'', which literally means "disordered breathing". Its combining form
Neoclassical compounds are compound words composed from combining forms (which act as affixes or stems) derived from classical Latin or ancient Greek roots. New Latin comprises many such words and is a substantial component of the technical an ...
s ('' dys-'' + '' -pnea'') are familiar from other medical words, such as ''dysfunction'' ('' dys-'' + ''function
Function or functionality may refer to:
Computing
* Function key, a type of key on computer keyboards
* Function model, a structured representation of processes in a system
* Function object or functor or functionoid, a concept of object-oriente ...
'') and '' apnea'' ('' a-'' + '' -pnea''). The most common pronunciation in medical English is , with the ''p'' expressed and the stress
Stress may refer to:
Science and medicine
* Stress (biology), an organism's response to a stressor such as an environmental condition
* Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
on the /niː/ syllable. But pronunciations with a silent ''p'' in ''pn'' (as also in '' pneumo-'') are common ( or ), as are those with the stress on the first syllable ( or ).
In English, the various ''-pnea''- suffixed words commonly used in medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...
do not follow one clear pattern as to whether the /niː/ syllable or the one preceding it is stressed; the ''p'' is usually expressed but is sometimes silent depending on the word. The following collation
Collation is the assembly of written information into a standard order. Many systems of collation are based on numerical order or alphabetical order, or extensions and combinations thereof. Collation is a fundamental element of most office filin ...
or list shows the preponderance of how major dictionaries pronounce and transcribe them (less-used variants are omitted):
See also
* List of terms of lung size and activity
Following are terms that specify a type of lung size and/or activity. More specific definitions may be found in individual articles.
* Eupnea – normal breathing
* Apnea – absence of breathing
* Bradypnea – decreased breathing rate
*Dyspnea or ...
* Bronchospasm
Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes di ...
* Orthopnea
Orthopnea or orthopnoea is shortness of breath (dyspnea) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. It is commonly seen as a late manifestation of heart failure, resulting from fluid ...
References
External links
Shortness Of Breath (Dyspnea)
nowiki
StatPearls
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Breathing abnormalities