www.diseases-diagnosis.com Homepage Diseases Symptoms Diseases Diagnosis Diseases Treatment Diseases Living Care Diseases Prevention Diseases Research
March 26, 2016
Table of Contents

1 Introduction
shortness of breath



Dyspnea (also spelled dyspnoea ) or ( shortness of breath (SOB), air hunger ), is the subjective symptom of breathlessness .

Dyspnea does not have a well defined or universally accepted definition. "uncomfortable awareness of breathing",

Acute breathlessness is defined as severe shortness of breath that develops over minutes to hours. Chronic breathlessness on the other hand comes on over weeks or months.

While shortness of breath is generally caused by disorders of the cardiac or respiratory system other system such as musculoskeletal , endocrine , hematologic , and psychiatric maybe the cause. DiagnosisPro, an online medical expert system, listed 497 distinct causes in October of 2010. The most common cardiovascular causes are acute myocardial infarction and congestive heart failure while common pulmonary causes include: chronic obstructive pulmonary disease, asthma, pneumothorax, and pneumonia.

Acute coronary syndrome

Acute coronary syndrome frequently presents with retrosternal chest discomfort and difficulty catching the breath.

Congestive heart failure

Congestive heart failure frequently presents with SOB with exertion, orthopnea, and paroxysmal nocturnal dyspnea.

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.


Asthma is the most common reason for presenting to the emergency with shortness of breath.


Pneumothorax presents typically with pleuritic chest pain of acute onset and shortness of breath not improved with oxygen.


The symptoms of pneumonia are fever, productive cough, shortness of breath, and pleuritic chest pain.

Pulmonary embolism

Pulmonary embolism classically presents with an acute onset of shortness of breath.


Other important or common causes of shortness of breath include: cardiac tamponade, anemia, anaphylaxis, interstitial lung disease and panic attacks.

A number of different physiological pathway may lead to shortness of breath including via chemoreceptors, mechanoreceptors, and lung receptors.

It is currently thought that there are three main components that contribute to dyspnea: afferent signals, efferent signals, and central information processing. It is believed that the central processing in the brain compares the afferent and efferent signals, and that a "mismatch" results in the sensation of dyspnea. In other words, dyspnea may result when the need for ventilation (afferent signaling) is not being met by the physical breathing that is occurring (efferent signaling).

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.

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. It is worth noting that there is a psychological component of dyspnea as well, as some people may become aware of their breathing in such circumstances but not experience the distress typical of dyspnea.

MRC Breathlessness Scale
Grade Degree of dyspnea
0no dyspnea except with strenuous exercise
1dyspnea when walking up an incline or hurrying on the level
2walks slower than most on the level, or stops after 15 minutes of walking on the level
3stops after a few minutes of walking on the level
4with minimal activity such as getting dressed, too dyspneic to leave the house

The initial approach to evaluation begins by assessment of the airway, breathing, and circulation followed by a medical history and physical examination.

A number of scales may be used to quantify the degree of shortness of breath.

Blood tests

A number of labs maybe helpful in determining 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 a number of conditions that lead to shortness of breath.


A chest x-ray is useful to confirm or rule out a pneumothorax, pulmonary edema, or pneumonia.

In those who are none palliative the primary treatment of shortness of breath is directed at its underlying cause.


Along with the measure above systemic immediate release opioids are beneficial in reducing the symptom of shortness of breath due to both cancer and non cancer causes. There is a lack of evidence to recommend midazolam, nebulised opioids, the use of gas mixtures, or cognitive-behavioral therapy.

Shortness of breath is the primary reason 3.5% of people present to the emergency department in the United States. Of these approximately 51% are admitted to hospital and 13% are dead within a year. Some studies have suggested that up to 27% of people suffer from dyspnea,

Dyspnea ( ), (from Latin dyspnoea , from Greek dyspnoia from dyspnoos ) literally means disordered breathing.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "shortness of breath".

Last Modified:   2010-11-25

All informatin on the site is © www.diseases-diagnosis.com 2002-2011. Last revised: January 2, 2011
Are you interested in our site or/and want to use our information? please read how to contact us and our copyrights.
To let us provide you with high quality information, you can help us by making a more or less donation: