Abnormal breathing

Shortness of breath, also known as dyspnea, is the feeling that one cannot 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 the distinct sensations, the degree of distress involved, and its burden or impact on activities of daily living. Distinct sensations include effort/work, chest tightness, and air hunger (the feeling of not enough oxygen).The American Thoracic Society defines dyspnea as: 'A subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity.' Other definitions 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).While shortness of breath is generally caused by disorders of the cardiac or respiratory system, other systems such as neurological, musculoskeletal, endocrine, hematologic, and psychiatric 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 and congestive heart failure while common pulmonary causes include chronic obstructive pulmonary disease, asthma, pneumothorax, pulmonary edema and pneumonia. 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 system.Different physiological pathways may lead to shortness of breath including via ASIC chemoreceptors, mechanoreceptors, and lung receptors.The initial approach to evaluation begins by assessment of the airway, breathing, and circulation followed by a medical history and physical examination. Signs 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.The primary treatment of shortness of breath is directed at its underlying cause. Extra oxygen is effective in those with hypoxia; however, this has no effect in those with normal blood oxygen saturations.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 people suffer from dyspnea, while in dying patients 75% will experience it. Acute shortness of breath is the most common reason people requiring palliative care visit an emergency department.English dyspnea comes from Latin dyspnoea, from Greek dyspnoia, from dyspnoos, which literally means 'disordered breathing'. 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 /dɪspˈniːə/ disp-NEE-ə, 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 (/dɪsˈniːə/ or /ˈdɪsniə/), as are those with the stress on the first syllable (/ˈdɪspniə/ or /ˈdɪsniə/).