Shortness of breath

Template:Short description Template:Redirect-distinguish Template:Infobox medical condition (new) Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American 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's activities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen).<ref name=Mahler>Template:Cite book</ref> The tripod position is often assumed to be a sign.

Dyspnea is a normal symptom of heavy physical exertion but becomes pathological if it occurs in unexpected situations,<ref name=Shiber06/> when resting or during light exertion. In 85% of cases it is due to asthma, pneumonia, reflux/LPR, cardiac ischemia, COVID-19, interstitial lung disease, congestive heart failure, chronic obstructive pulmonary disease, or psychogenic causes,<ref name=Shiber06>Template:Cite journal</ref><ref name=Pal2010/> such as panic disorder and anxiety Template:Crossreference.<ref>Template:Cite book</ref> The best treatment to relieve or even remove shortness of breath<ref>Kelvin, Joanne Frankel; Tyson, Leslie B. 100 Questions & Answers About Cancer Symptoms and Cancer Treatment Side Effects. 2nd Edition. 2011. Template:ISBN?Template:Page needed</ref> typically depends on the underlying cause.<ref name=Z2009/>

Definition

Dyspnea, in medical terms, is "shortness of breath".

The American Thoracic Society defines dyspnea as:

"A subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity."<ref name="AmericanThoracicSociety">Template:Cite journal</ref>

Other definitions describe it as "difficulty in breathing",<ref>TheFreeDictionary Template:Webarchive, 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</ref> "disordered or inadequate breathing",<ref name="Uptodate">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> "uncomfortable awareness of breathing",<ref name="Pal2010" /> and as the experience of "breathlessness" (which may be either acute or chronic).<ref name="Shiber06" /><ref name="Z2009">Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Causes

While shortness of breath is generally caused by disorders of the cardiac or respiratory system, others such as the neurological,<ref name="ch8139" /> musculoskeletal, endocrine, gastrointestinal system (reflux/LPR)<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>,hematologic,and psychiatric systems may be the cause.<ref name=Sarkar2006>Template:Cite journal</ref> DiagnosisPro, an online medical expert system, listed 497 distinct causes in October 2010.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The most common cardiovascular causes are myocardial infarction and heart failure while common pulmonary causes include chronic obstructive pulmonary disease, asthma, pneumothorax, pulmonary edema and pneumonia.<ref name=Shiber06/> On a pathophysiological basis the causes can be divided into (1) 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.<ref name="ch8139">Template:Cite book</ref> Ischemic strokes, hemorrhages, tumors, infections, seizures, and traumas at the brain stem can also cause shortness of breath, making them the only neurological causes of shortness of breath.Template:Cn

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, bronchospasm, myocardial infarction, pulmonary embolism, or pneumothorax. 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.<ref>D. L. Kasper et al. (ed), Harrison's Principles of Internal Medicine, 20th edition (2018), p. 1943</ref>

Acute coronary syndrome

Acute coronary syndrome frequently presents with retrosternal chest discomfort and difficulty catching the breath.<ref name=Shiber06/> It however may atypically present with shortness of breath alone.<ref name=Old2007/> Risk factors include old age, smoking, hypertension, hyperlipidemia, and diabetes.<ref name=Old2007/> An electrocardiogram and cardiac enzymes are important both for diagnosis and directing treatment.<ref name=Old2007/> Treatment involves measures to decrease the oxygen requirement of the heart and efforts to increase blood flow.<ref name=Shiber06/>

COVID-19

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} People that have been infected by COVID-19 may have symptoms such as a fever, dry cough, loss of smell and taste, and in moderate to severe cases, shortness of breath.Template:Citation needed

Congestive heart failure

Congestive heart failure frequently presents with shortness of breath with exertion, orthopnea, and paroxysmal nocturnal dyspnea.<ref name=Shiber06/> It affects between 1 and 2% of the general United States population and occurs in 10% of those over 65 years old.<ref name=Shiber06/><ref name=Old2007/> Risk factors for acute decompensation include high dietary salt intake, medication noncompliance, cardiac ischemia, abnormal heart rhythms, kidney failure, pulmonary emboli, hypertension, and infections.<ref name=Old2007/> Treatment efforts are directed toward decreasing lung congestion.<ref name=Shiber06/>

Chronic obstructive pulmonary disease

People with chronic obstructive pulmonary disease (COPD), most commonly emphysema or chronic bronchitis, frequently have chronic shortness of breath and a chronic productive cough.<ref name=Shiber06/> An acute exacerbation presents with increased shortness of breath and sputum production.<ref name=Shiber06/> COPD is a risk factor for pneumonia; thus this condition should be ruled out.<ref name=Shiber06/> In an acute exacerbation treatment is with a combination of anticholinergics, beta₂-adrenoceptor agonists, steroids and possibly positive pressure ventilation.<ref name=Shiber06/>

Asthma

Asthma is the most common reason for presenting to the emergency room with shortness of breath.<ref name=Shiber06/> It is the most common lung disease in both developing and developed countries affecting about 5% of the population.<ref name=Shiber06/> Other symptoms include wheezing, tightness in the chest, and a nonproductive cough.<ref name=Shiber06/> Inhaled corticosteroids are the preferred treatment for children, however, these drugs can reduce the growth rate.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Acute symptoms are treated with short-acting bronchodilators.Template:Citation needed

Pneumothorax

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Pneumothorax presents typically with pleuritic chest pain of acute onset and shortness of breath not improved with oxygen.<ref name=Shiber06/> Physical findings may include absent breath sounds on one side of the chest, jugular venous distension, and tracheal deviation.<ref name=Shiber06/>

Pneumonia

The symptoms of pneumonia are fever, productive cough, shortness of breath, and pleuritic chest pain.<ref name=Shiber06/> Inspiratory crackles may be heard on exam.<ref name=Shiber06/> A chest x-ray can be useful to differentiate pneumonia from congestive heart failure.<ref name=Shiber06/> As the cause is usually a bacterial infection, antibiotics are typically used for treatment.<ref name=Shiber06/>

Pulmonary embolism

Pulmonary embolism classically presents with an acute onset of shortness of breath.<ref name=Shiber06/> Other presenting symptoms include pleuritic chest pain, cough, hemoptysis, and fever.<ref name=Shiber06/> Risk factors include deep vein thrombosis, recent surgery, cancer, and previous thromboembolism.<ref name=Shiber06/> It must always be considered in those with acute onset of shortness of breath owing to its high risk of mortality.<ref name=Shiber06/> Diagnosis, however, may be difficult<ref name=Shiber06/> and Wells Score is often used to assess the clinical probability. Treatment, depending on the severity of symptoms, typically starts with anticoagulants; the presence of ominous signs (low blood pressure) may warrant the use of thrombolytic drugs.<ref name=Shiber06/>

Anemia

Anemia that develops gradually usually presents with exertional dyspnea, fatigue, weakness, and tachycardia.<ref name=Will2010/> It may lead to heart failure.<ref name=Will2010/> 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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>Template:Citation needed

Cancer

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.<ref name="Haywood-2019">Template:Cite journal</ref> 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.<ref name=":0" /> 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.<ref name=":0">Template:Cite report</ref> Integrative medicine options including acupuncture, acupressure, reflexology, and meditation have been found to have a beneficial effect.<ref>Template:Cite journal</ref>

Other

Other important or common causes of shortness of breath include cardiac tamponade, anaphylaxis, interstitial lung disease, panic attacks,<ref name=Z2009/><ref name=Sarkar2006/><ref name=Will2010>Template:Cite journal</ref> and pulmonary hypertension. It is more common among people with relatively small lungs.<ref>Template:Cite journal</ref> Around 2/3 of women experience shortness of breath as a part of a normal pregnancy.<ref name=Uptodate/>

Cardiac tamponade presents with dyspnea, tachycardia, elevated jugular venous pressure, and pulsus paradoxus.<ref name=Will2010/> The gold standard for diagnosis is ultrasound.<ref name=Will2010/>

Anaphylaxis typically begins over a few minutes in a person with a previous history of the same.<ref name=Z2009/> Other symptoms include urticaria, throat swelling, and gastrointestinal upset.<ref name=Z2009/> The primary treatment is epinephrine.<ref name=Z2009/>

Interstitial lung disease presents with a gradual onset of shortness of breath typically with a history of predisposing environmental exposure.<ref name=Sarkar2006/> Shortness of breath is often the only symptom in those with tachydysrhythmias.<ref name=Old2007/>

Panic attacks typically present with hyperventilation, sweating, and numbness.<ref name=Z2009/> They are however a diagnosis of exclusion.<ref name=Sarkar2006/>

Neurological conditions such as spinal cord injury, phrenic nerve injuries, Guillain–Barré syndrome, amyotrophic lateral sclerosis, multiple sclerosis and muscular dystrophy can all cause an individual to experience shortness of breath.<ref name="ch8139" /> Shortness of breath can also occur as a result of vocal cord dysfunction (VCD).<ref>Template:Cite journal</ref>

Dyspnea can be a symptom of mast cell activation syndrome (MCAS).<ref name="PMID27012973">Template:Cite journal</ref><ref name="PMID38948000">Template:Cite journal</ref>

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.<ref>Template:Cite book</ref>

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 such inflammatory response, and it causes respiratory symptoms such as coughing and dyspnea.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Pathophysiology

Different physiological pathways may lead to shortness of breath including via ASIC chemoreceptors, mechanoreceptors, and lung receptors.<ref name=Old2007>Template:Cite journal</ref>

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).<ref name=Harrisons />

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, lungs, and chest wall. Chemoreceptors in the carotid bodies and medulla supply information regarding the blood gas levels of O₂, CO₂ and H⁺.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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 to hypercapnia, 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.<ref name=Harrisons />

Efferent signals are the motor neuronal signals descending to the respiratory muscles. The most important respiratory muscle is the diaphragm. Other respiratory muscles include the external and internal intercostal muscles, the abdominal muscles, and the accessory breathing muscles.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name=Harrisons />

Diagnosis

MRC breathlessness scale

Grade	Degree of dyspnea
1	no dyspnea except with strenuous exercise
2	dyspnea when walking up an incline or hurrying on the level
3	walks slower than most on the level, or stops after 15 minutes of walking on the level
4	stops after a few minutes of walking on the level
5	with minimal activity such as getting dressed, too dyspneic to leave the house

File:Signs of respiratory distress illustration.png

Signs of respiratory distress illustration

The initial approach to evaluation begins with an assessment of the airway, breathing, and circulation followed by a medical history and physical examination.<ref name=Shiber06/> Signs and symptoms that represent significant severity include hypotension, hypoxemia, tracheal deviation, altered mental status, unstable dysrhythmia, stridor, intercostal indrawing, cyanosis, tripod positioning, pronounced use of accessory muscles (sternocleidomastoid, scalenes) and absent breath sounds.<ref name=Sarkar2006/>

A number of scales may be used to quantify the degree of shortness of breath.<ref name=Rate2007>Template:Cite journal</ref> It may be subjectively rated on a scale from 1 to 10 with descriptors associated with the number (The Modified Borg Scale).<ref name=Rate2007/> The MRC breathlessness scale suggests five grades of dyspnea based on the circumstances and severity in which it arises.<ref name="Williams">Template:Cite journal</ref>

Blood tests

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.<ref name=Old2007/> A low level of brain 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.<ref name=Old2007/>

Imaging

A chest x-ray is useful to confirm or rule out a pneumothorax, pulmonary edema, or pneumonia.<ref name=Old2007/> Spiral computed tomography with intravenous radiocontrast is the imaging study of choice to evaluate for pulmonary embolism.<ref name=Old2007/>

Treatment

The primary treatment of shortness of breath is directed at its underlying cause.<ref name=Z2009/> Extra supplemental oxygen is effective in those with hypoxia; however, this has no effect in those with normal blood oxygen saturations.<ref name=Pal2010/><ref>Template:Cite journal</ref>

Physiotherapy

Individuals can benefit from a variety of physical therapy interventions.<ref>Template:Cite book</ref> Persons with neurological/neuromuscular abnormalities may have breathing difficulties due to weak or paralyzed intercostal, abdominal and/or other muscles needed for ventilation.<ref>Template:Cite book</ref> Some physical therapy interventions for this population include active assisted cough techniques,<ref>Template:Cite book</ref> volume augmentation such as breath stacking,<ref name="ch32">Template:Cite book</ref> education about body position and ventilation patterns<ref>Template:Cite book</ref> and movement strategies to facilitate breathing.<ref name="ch32" /> Pulmonary rehabilitation may alleviate symptoms in some people, such as those with COPD, but will not cure the underlying disease.<ref name=Puh2016>Template:Cite journal</ref><ref name=Zainuldin>Template:Cite journal</ref> Fan therapy to the face has been shown to relieve shortness of breath in patients with a variety of advanced illnesses including cancer.<ref>Template:Cite journal</ref> The mechanism of action is thought to be stimulation of the trigeminal nerve.Template:Cn

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;<ref name=Pal2010/><ref>Template:Cite journal</ref> 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, nebulised opioids, the use of gas mixtures, or cognitive-behavioral therapy yet.<ref>Template:Cite journal</ref>

Non-pharmacological techniques

Non-pharmacological interventions provide key tools for the management of breathlessness.<ref name="Haywood-2019" /> Potentially beneficial approaches include active management of psychosocial issues (anxiety, depression, etc.), and implementation of self-management strategies, such as physical and mental relaxation techniques, pacing techniques, energy conservation techniques, learning exercises to control breathing, and education.<ref name="Haywood-2019" /> The use of a fan may be beneficial.<ref name="Haywood-2019" /> Cognitive behavioural therapy may also be helpful.<ref name="Haywood-2019" />

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.<ref name="Haywood-2019" /> Results of recent systematic reviews and meta-analyses found opioids were not necessarily associated with more effectiveness in treatment for patients with advanced cancer.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

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.<ref name="Haywood-2019" /> 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.<ref name="Haywood-2019" />

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% die within a year.<ref>Template:Cite book</ref> Some studies have suggested that up to 27% of hospitalized people develop dyspnea,<ref name=Murray>Murray and Nadel's Textbook of Respiratory Medicine, 4th Ed. Robert J. Mason, John F. Murray, Jay A. Nadel, 2005, Elsevier</ref> while in dying patients 75% will experience it.<ref name=Harrisons>Harrison's Principles of Internal Medicine (Kasper DL, Fauci AS, Longo DL, et al. (eds)) (16th ed.). New York: McGraw-Hill.</ref> Acute shortness of breath is the most common reason people requiring palliative care visit an emergency department.<ref name=Pal2010>Template:Cite journal</ref> Up to 70% of adults with advanced cancer also experience dyspnoea.<ref name="Haywood-2019" />

Etymology and pronunciation

English dyspnea comes from Latin dyspnoea, from Greek dyspnoia, from dyspnoos, which literally means "disordered breathing".<ref name=Sarkar2006/><ref>Template:Citation</ref> Its combining forms (dys- + -pnea) are familiar from other medical words, such as dysfunction (dys- + function) and apnea (a- + -pnea). The most common pronunciation in medical English is Template:IPAc-en Template:Respell, with the p expressed and the stress on the /niː/ syllable. But pronunciations with a silent p in pn (as also in pneumo-) are common (Template:IPAc-en or Template:IPAc-en),<ref name="MW_Medical">Template:Citation</ref> as are those with the stress on the first syllable<ref name="MW_Medical"/> (Template:IPAc-en or Template:IPAc-en).

In English, the various -pnea-suffixed words commonly used in medicine 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 or list shows the preponderance of how major dictionaries pronounce and transcribe them (less-used variants are omitted): Template:Anchor

Group	Term	Combining forms	Preponderance of transcriptions (major dictionaries)
good	eupnea	eu- + -pnea	Template:IPAc-en Template:Respell<ref name="Dorlands">Template:Citation</ref><ref name="Stedmans">Template:Citation</ref><ref name="MW_Medical"/><ref name="AHD">Template:Citation</ref>
bad	dyspnea	dys- + -pnea	Template:IPAc-en Template:Respell,<ref name="Stedmans"/><ref name="AHD"/><ref name="OxfordDictionaries">Template:Citation</ref> Template:IPAc-en Template:Respell<ref name="Dorlands"/><ref name="MW_Medical"/>
fast	tachypnea	tachy- + -pnea	Template:IPAc-en Template:Respell<ref name="Dorlands"/><ref name="Stedmans"/><ref name="MW_Medical"/><ref name="AHD"/><ref name="OxfordDictionaries"/>
slow	bradypnea	brady- + -pnea	Template:IPAc-en Template:Respell<ref name="Stedmans"/><ref name="MW_Medical"/><ref name="AHD"/>
upright	orthopnea	ortho- + -pnea	Template:IPAc-en Template:Respell,<ref name="Stedmans"/><ref name="MW_Medical"/><ref name="OxfordDictionaries"/><ref name="Dorlands"/>Template:Rp Template:IPAc-en Template:Respell<ref name="MW_Medical"/><ref name="Dorlands"/>Template:Rp
supine	platypnea	platy- + -pnea	Template:IPAc-en Template:Respell<ref name="Dorlands"/><ref name="Stedmans"/>
bent over	bendopnea	bend + -o- + -pnea	Template:IPAc-en Template:Respell
excessive	hyperpnea	hyper- + -pnea	Template:IPAc-en Template:Respell<ref name="Dorlands"/><ref name="Stedmans"/><ref name="MW_Medical"/><ref name="AHD"/>
insufficient	hypopnea	hypo- + -pnea	Template:IPAc-en Template:Respell,<ref name="Dorlands"/><ref name="Stedmans"/><ref name="AHD"/><ref name="OxfordDictionaries"/> Template:IPAc-en Template:Respell<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref><ref name="AHD"/>
absent	apnea	a- + -pnea	Template:IPAc-en Template:Respell,<ref name="Dorlands"/><ref name="Stedmans"/><ref name="MW_Medical"/><ref name="AHD"/><ref name="OxfordDictionaries"/>Template:Rp Template:IPAc-en Template:Respell<ref name="MW_Medical"/><ref name="AHD"/><ref name="OxfordDictionaries"/>Template:Rp

See also

• List of terms of lung size and activity
• Bronchospasm
• Orthopnea

External links

Template:Sister projectShortness Of Breath (Dyspnea)StatPearlsTemplate:Medical resources