Shortness of breath (SOB), known asdyspnea (inAmE) ordyspnoea (inBrE), is an uncomfortable feeling of not being able to breathe well enough. TheAmerican Thoracic Society 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'sactivities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen).[1] Thetripod position is often assumed to be a sign.
"A subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity."[7]
Other definitions describe it as "difficulty in breathing",[8] "disordered or inadequate breathing",[9] "uncomfortable awareness of breathing",[3] and as the experience of "breathlessness" (which may be either acute or chronic).[2][6][10]
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 aslaryngeal edema,bronchospasm,myocardial infarction,pulmonary embolism, orpneumothorax. 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.[14]
People that have been infected byCOVID-19 may have symptoms such as a fever, dry cough, loss of smell and taste, and in moderate to severe cases, shortness of breath.[citation needed]
Asthma is the most common reason for presenting to the emergency room with shortness of breath.[2] It is the most common lung disease in both developing and developed countries affecting about 5% of the population.[2] Other symptoms includewheezing, tightness in the chest, and a nonproductive cough.[2]Inhaledcorticosteroids are the preferred treatment for children, however, these drugs can reduce the growth rate.[16] Acute symptoms are treated with short-acting bronchodilators.[citation needed]
Pneumothorax presents typically withpleuritic chest pain of acute onset and shortness of breath not improved with oxygen.[2] Physical findings may include absent breath sounds on one side of the chest,jugular venous distension, and tracheal deviation.[2]
Pulmonary embolism classically presents with an acute onset of shortness of breath.[2] Other presenting symptoms includepleuritic chest pain, cough,hemoptysis, andfever.[2] Risk factors includedeep vein thrombosis, recent surgery,cancer, and previousthromboembolism.[2] It must always be considered in those with acute onset of shortness of breath owing to its high risk of mortality.[2] Diagnosis, however, may be difficult[2] andWells Score is often used to assess the clinical probability. Treatment, depending on the severity of symptoms, typically starts withanticoagulants; the presence of ominous signs (low blood pressure) may warrant the use ofthrombolytic drugs.[2]
Anemia that develops gradually usually presents with exertional dyspnea, fatigue, weakness, andtachycardia.[17] It may lead toheart failure.[17] Anaemia is often a cause of dyspnea.Menstruation, particularly if excessive, can contribute to anaemia and consequential dyspnea in women. Headaches are 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 reported severe head pains, which can lead to permanent brain damage. Symptoms can include loss of concentration, focus, fatigue, language faculty impairment, and memory loss.[18][citation needed]
Shortness of breath is common in people with cancer and may be caused by numerous different factors. In people with advanced cancer, periods with severe shortness of breath may occur, along with a more continuous feeling of breathlessness.[19] Treatments for breathlessness include both nonpharmacological and pharmacological approaches. Nonpharmacological interventions that have shown to improve breathlessness include the use of fans, exercise, and pulmonary rehabilitation.[20] Pharmacological treatments involve bronchodilators and corticosteroids to address the underlying causes of shortness of breath, as well as opioids or anti-anxiety medications to alleviate symptoms.[20] Integrative medicine options including acupuncture, acupressure, reflexology, and meditation have been found to have a beneficial effect.[21]
Cardiac tamponade presents with dyspnea, tachycardia, elevated jugular venous pressure, andpulsus paradoxus.[17] The gold standard for diagnosis isultrasound.[17]
Anaphylaxis typically begins over a few minutes in a person with a previous history of the same.[6] Other symptoms includeurticaria,throat swelling, and gastrointestinal upset.[6] The primary treatment isepinephrine.[6]
Interstitial lung disease presents with a gradual onset of shortness of breath typically with a history of predisposing environmental exposure.[12] Shortness of breath is often the only symptom in those withtachydysrhythmias.[15]
Sarcoidosis 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 the involvement of sites such as the eyes, the skin, and the joints.[26]
In January 2025, Metro reported that vaping increases the risk of inflammation of the lungs by exposing users to the vaporized elements of the oil.popcorn lung is considered to be one of the inflammatory responses, and it causes respiratory symptoms such as coughing and dyspnea.[27]
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).[28]
Afferent signals are sensory neuronal signals that ascend to the brain. Afferent neurons significant in dyspnea arise from a large number of sources including thecarotid bodies,medulla,lungs, andchest wall. Chemoreceptors in the carotid bodies and medulla supply information regarding the blood gas levels of O2, CO2 and H+.[29] In the lungs,juxtacapillary (J) receptors are sensitive to pulmonary interstitial edema, while stretch receptors signal bronchoconstriction.Muscle spindles in the chest wall signal the stretch and tension of the respiratory muscles. Thus, poor ventilation leads tohypercapnia,left heart failure leading to interstitial edema (impairing gas exchange),asthma causing bronchoconstriction (limiting airflow) and muscle fatigue leading to ineffective respiratory muscle action could all contribute to a feeling of dyspnea.[28]
Efferent signals are the motor neuronal signals descending to therespiratory muscles. The most important respiratory muscle is thediaphragm. Other respiratory muscles include the external and internalintercostal muscles, the abdominal muscles, and the accessory breathing muscles.[30] As the brain receives its plentiful supply of afferent information relating to ventilation, it can 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.[28]
A number of scales may be used to quantify the degree of shortness of breath.[31] It may be subjectively rated on a scale from 1 to 10 with descriptors associated with the number (The ModifiedBorg Scale).[31] TheMRC breathlessness scale suggests five grades of dyspnea based on the circumstances and severity in which it arises.[32]
Several labs may help determine the cause of shortness of breath.D-dimer, 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 several conditions that lead to shortness of breath.[15] A low level ofbrain natriuretic peptide 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, acute coronary syndrome, or a large pulmonary embolism.[15]
The primary treatment of shortness of breath is directed at its underlying cause.[6] Extra supplementaloxygen is effective in those withhypoxia; however, this has no effect in those with normalblood oxygen saturations.[3][33]
Individuals can benefit from a variety ofphysical therapy interventions.[34] Persons with neurological/neuromuscular abnormalities may have breathing difficulties due to weak or paralyzed intercostal, abdominal and/or other muscles needed forventilation.[35] Some physical therapy interventions for this population include active assistedcough techniques,[36] volume augmentation such as breath stacking,[37] education about body position and ventilation patterns[38] and movement strategies to facilitate breathing.[37]Pulmonary rehabilitation may alleviate symptoms in some people, such as those with COPD, but will not cure the underlying disease.[39][40] Fan therapy to the face has been shown to relieve shortness of breath in patients with a variety of advanced illnesses including cancer.[41] The mechanism of action is thought to be stimulation of the trigeminal nerve.[citation needed]
Systemic immediate releaseopioids are beneficial in emergently reducing the symptom severity of shortness of breath due to both cancer and non-cancer causes;[3][42] long-acting/sustained-release opioids are also used to prevent/continue treatment of dyspnea in palliative setting. There is a lack of evidence to recommendmidazolam, nebulised opioids, the use of gas mixtures, orcognitive-behavioral therapy yet.[43]
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.[19] Results of recent systematic reviews and meta-analyses found opioids were not necessarily associated with more effectiveness in treatment for patients with advanced cancer.[44][45]
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.[19] The use of systematic corticosteroids in palliative care for people with cancer is common, however, the effectiveness and potential adverse effects of this approach in adults with cancer have not been well studied.[19]
Shortness of breath is the primary reason 3.5% of people present to theemergency department in the United States. Of these individuals, approximately 51% are admitted to the hospital and 13% die within a year.[46] Some studies have suggested that up to 27% of hospitalized people develop dyspnea,[47] while in dying patients 75% will experience it.[28] Acute shortness of breath is the most common reason people requiringpalliative care visit an emergency department.[3] Up to 70% of adults with advanced cancer also experience dyspnoea.[19]
In English, the various-pnea-suffixed words commonly used inmedicine do not follow one clear pattern as to whether the /niː/ syllable or the one preceding it is stressed; thep is usually expressed but is sometimes silent depending on the word. The followingcollation or list shows thepreponderance of how major dictionaries pronounce and transcribe them (less-used variants are omitted):
Group
Term
Combining forms
Preponderance of transcriptions (major dictionaries)
^Mukerji, Vaskar (1990)."11".Dyspnea, Orthopnea, and Paroxysmal Nocturnal Dyspnea. Butterworth Publishers.ISBN9780409900774.PMID21250057.Archived from the original on 27 April 2018. Retrieved15 August 2014.In addition, dyspnea may occur in febrile and hypoxic states and in association with some psychiatric conditions such as anxiety and panic disorder.
^Kelvin, Joanne Frankel; Tyson, Leslie B.100 Questions & Answers About Cancer Symptoms and Cancer Treatment Side Effects. 2nd Edition. 2011.[ISBN missing][page needed]
^American Heart Society (1999). "Dyspnea mechanisms, assessment, and management: a consensus statement".American Journal of Respiratory and Critical Care Medicine.159 (1):321–40.doi:10.1164/ajrccm.159.1.ats898.PMID9872857.
^TheFreeDictionaryArchived 2019-06-05 at theWayback Machine, retrieved on Dec 12, 2009. Citing:The American Heritage Dictionary of the English Language, Fourth Edition by Houghton Mifflin Company. Updated in 2009. Ologies & -Isms. The Gale Group 2008
^ab"UpToDate".www.uptodate.com.Archived from the original on 2020-03-26. Retrieved2022-04-25.
^abcFrownfelter, Donna; Dean, Elizabeth (2006). "8". In Willy E. Hammon III (ed.).Cardiovascular and Pulmonary Physical Therapy. Vol. 4. Mosby Elsevier. p. 139.
^abcdeWills CP, Young M, White DW (February 2010). "Pitfalls in the evaluation of shortness of breath".Emerg. Med. Clin. North Am.28 (1):163–81, ix.doi:10.1016/j.emc.2009.09.011.PMID19945605.
^abSaracino A (October 2007). "Review of dyspnoea quantification in the emergency department: is a rating scale for breathlessness suitable for use as an admission prediction tool?".Emergency Medicine Australasia.19 (5):394–404.doi:10.1111/j.1742-6723.2007.00999.x.PMID17919211.S2CID29642138.
^Frownfelter, Donna; Dean, Elizabeth (2006). "8". In Willy E. Hammon III (ed.).Cardiovascular and Pulmonary Physical Therapy. Vol. 4. Mosby Elsevier.
^Frownfelter, Donna; Dean, Elizabeth (2006). "22". In Donna Frownfelter; Mary Massery (eds.).Cardiovascular and Pulmonary Physical Therapy. Vol. 4. Mosby Elsevier. p. 368.
^Frownfelter, Donna; Dean, Elizabeth (2006). "22". In Donna Frownfelter; Mary Massery (eds.).Cardiovascular and Pulmonary Physical Therapy. Vol. 4. Mosby Elsevier. pp. 368–71.
^abFrownfelter, Donna; Dean, Elizabeth (2006). "32".Cardiovascular and Pulmonary Physical Therapy. Vol. 4. Mosby Elsevier. pp. 569–81.
^Frownfelter, Donna; Dean, Elizabeth (2006). "23". In Donna Frownfelter; Mary Massery (eds.).Cardiovascular and Pulmonary Physical Therapy. Vol. 4. Mosby Elsevier.
^Naqvi F, Cervo F, Fields S (August 2009). "Evidence-based review of interventions to improve palliation of pain, dyspnea, depression".Geriatrics.64 (8):8–10,12–14.PMID20722311.
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