Dyspnea : Causes, Symptoms, Diagnosis & Treatment

Last Updated: 27/08/2022

Shortness of breath (dyspnea) is a violation of the function of external respiration, accompanied by both objective symptoms and a subjective feeling of lack of air. The development of dyspnea is caused by pathologies of the respiratory and cardiovascular systems, anemia. The symptom may occur due to organic lesions of the central nervous system, neurotic disorders, metabolic disorders. To identify the cause of shortness of breath, spirometry, radiography, ECG, ultrasound, and laboratory tests are performed. To reduce symptoms, non-drug methods are used, the underlying disease is corrected.

general characteristics

Shortness of breath is perceived by patients as a subjective feeling of lack of air, inefficiency of respiratory movements, tightness in the chest. The symptom is accompanied by characteristic objective signs: increased or slowed down inhalations-exhalations, blanching or cyanosis of the nasolabial triangle, convulsive loud inhalation, suffocation. Often, to alleviate the condition, a person with dyspnea stops moving, takes a forced position - sits on a chair or bed, leans forward slightly, leaning on straight arms.

Most often, the appearance of shortness of breath is associated with physical exertion, and at the beginning of the disease, the disorder is provoked only by significant activity, and with progression, patients feel short of breath after normal activities. In addition to respiratory disorders, pathological symptoms are possible: pain and discomfort in the chest, headache, dizziness, decreased performance. If shortness of breath is noted during the performance of habitual work or at rest, it is necessary to seek the advice of a specialist.

Development mechanism

Shortness of breath is caused by many complex reflex mechanisms that involve higher nervous structures, so there are several theories of its development. The direct cause of the violation of the frequency and quality of breathing, many doctors call a change in the content of oxygen and carbon dioxide in the blood. An increase in carbon dioxide concentration, leading to a decrease in pH, has a significant stimulating effect on the bulbar centers, peripheral chemoreceptor zones of the arteries and central receptors located in the medulla oblongata.

At the same time, protective mechanisms are activated, the respiratory center of the brain stem sends activating impulses to the bronchopulmonary system, causing pathological rapid breathing. The appearance of shortness of breath is associated with impulses from the spindle-shaped nerve endings of the respiratory tract, which are activated due to various pathological processes. Sometimes an increased work of the respiratory center is observed with descending cortical influences caused by hysterical or neurotic states.

The connection of the symptom with the temperature of the internal environment of the body has been proved. With hyperthermia, the sensitive zones of the respiratory center are washed with warmer blood, which causes their activation - the so-called thermal shortness of breath occurs. A decrease in body temperature, on the contrary, leads to a decrease in respiratory movements. The development of dyspnea is affected by the amount of muscle load and the level of metabolism. Most researchers believe that this mechanism is due to two types of reactions - slow humoral and fast neurogenic.

Subjective sensations in the form of lack of air and suffocation are primarily associated with the spread of excessive excitation from the centers of the medulla oblongata to the limbic structures and the cerebral cortex. This causes the appearance of negative emotional reactions of fear and anxiety in patients with shortness of breath. Sometimes unpleasant symptoms develop due to a mismatch between the body's needs for ventilation and the functionality of the respiratory apparatus to provide it.



Shortness of breath can manifest itself in many diseases and pathological conditions, therefore, to facilitate the diagnostic search, it is necessary to accurately determine its type. The classification of a symptom is based on the mechanism of development, the degree of change in respiratory function, the ratio of inhalation-exhalation phases. There are physiological shortness of breath, when the frequency of inhalations and exhalations changes in proportion to physical activity, and pathological. Most often, the symptom is classified in relation to the respiratory phases:

  • Inspiratory dyspnea . This type of violation is manifested by a predominant difficulty in the inspiratory phase. Shortness of breath is detected in diseases of the diaphragm and pleura, heart failure, pulmonary fibrosis. Dyspnea in combination with noisy breathing is typical for pathologies of the trachea, large bronchi.
  • Expiratory dyspnea . The symptom is usually observed in violation of the patency of the small bronchi and bronchioles, typical of bronchial asthma. Shortness of breath on exhalation also occurs with chronic obstructive bronchitis, pneumosclerosis, and a decrease in the elasticity of the lung tissue as a result of emphysema.
  • Mixed dyspnea . Respiratory failure in both phases often develops with a severe stage of heart failure, progressive diseases of the respiratory system. This type of dyspnea can be associated with febrile conditions, CNS pathologies with direct irritation of the respiratory center.

Taking into account changes in respiratory function, several types of shortness of breath are distinguished: tachypnea - an increase in the frequency of breaths more than 4 per minute, bradypnea - a decrease in respiratory movements less than 12 per minute, apnea - a sudden stoppage of breathing. There is a classification of the symptom according to the main mechanism of development: central dyspnea is observed with organic or functional changes in the work of the respiratory center in the medulla oblongata, the neurogenic variant is associated with a weakening of inhibitory influences in the cerebral cortex, the hemic form develops with anemia.

Causes of shortness of breath

Causes of lack of air

A subjective feeling of difficulty in breathing can be observed in healthy people after intense physical exertion, in pregnant women. Pathological causes of the symptom are various disorders in the work of the respiratory and other body systems. Lack of air is caused by:

  • Lung diseases : croupous and interstitial pneumonias, tuberculosis, sclerotic processes and primary amyloidosis.
  • Pleurisy : dry, exudative, hemorrhagic.
  • Respiratory tract injuries : foreign bodies of the trachea, bronchi, thoracic trauma, pulmonary bleeding.
  • Laryngeal causes : false croup, laryngomalacia, neuropathic paresis.
  • Tumors : pleural cancer, bronchioloalveolar cancer, invasive thyroid cancer.
  • Acute conditions : cardiac asthma with heart attacks, heart defects, pulmonary embolism.
  • Neuroses : panic attack, vegetovascular dystonia, cardioneurosis.

Causes of difficulty exhaling

Expiratory dyspnea with convulsive short inhalation and prolonged exhalation is often a sign of various diseases of the bronchopulmonary system. The symptom is often accompanied by a feeling of tightness in the chest. Difficulty exhaling manifests the following pathological conditions:

  • Bronchial asthma : allergic, mixed, occupational.
  • Obstructive airway disease: bronchitis and COPD, bronchiectasis, stenosis of the trachea and bronchi.
  • Pulmonary pathology : pneumosclerosis, emphysema, alpha1-antitrypsin enzyme deficiency.
  • Occupational diseases : byssinosis, gasoline pneumonia.
  • Complications of pharmacotherapy : taking NSAIDs (especially aspirin), infusion of blood or plasma with a high content of citrates.
  • Rare causes : Williams-Campbell syndrome, Mendelssohn's syndrome, tumors in the bifurcation of the trachea.


Patients with complaints of lack of air or difficulty exhaling seek help from a specialist pulmonologist or local therapist. Diagnostic search involves laboratory and instrumental studies of the respiratory system, functional tests. The most informative to clarify the cause of shortness of breath are:

  • Assessment of external respiration . Spirometry is a non-invasive and affordable method of research, during which the main parameters of the respiratory system are recorded - lung capacity, forced expiratory volume in the first second. A bronchodilation test is indicated to differentiate between COPD and asthma.
  • X-ray examination . Performing a chest x-ray in 2 projections allows you to detect typical pathological changes (diffuse sclerosis, emphysema, volumetric formations), in which shortness of breath usually occurs. Further examination involves the use of computed tomography, MRI.
  • Laryngoscopy . To detect narrowing of the lumen of the larynx, visualization of foreign bodies, mucous membranes are examined using a special laryngoscope. In the absence of signs of damage, laryngoscopy is supplemented by tracheobronchoscopy for a detailed study of the structure of the bronchial tree with the collection of material for cytomorphological examination.
  • Electrocardiography. An ECG is done to rule out cardiac causes of dyspnea. With doubtful results in an expanded format, the cardiovascular system is examined: phonocardiography, ultrasound of the heart with Doppler sonography are prescribed. With probable periodic violations, Holter monitoring is used.
  • Laboratory tests . Evaluation of blood oxygen saturation and carbon dioxide levels is necessary to determine the degree of respiratory disorders. In the general blood test, signs of inflammatory processes (increased ESR, leukocytosis) may be noted. A biochemical blood test is also recommended.

To identify the etiological factor of shortness of breath, allergy tests are performed, the results of an extended immunogram are informative. If suspicious lesions are found on radiographs, a transbronchial lung biopsy is performed. For the diagnosis of rare congenital malformations, as a possible cause of dyspnea, specialized specialists are involved.

Inhaled bronchodilators are used to quickly relieve shortness of breath



Help before diagnosis

With a sharp onset of an attack of shortness of breath, the patient must be reassured, seated on a chair or bed so that the body is in an elevated position. To facilitate breathing, it is advisable to remove tight clothing, belt, unbutton the shirt collar. It is necessary to ensure the flow of fresh air into the room - open a window or door. Allowed to take herbal sedatives. The frequent occurrence of breathing difficulties indicates the development of the disease or the progression of existing diseases. In such a situation, it is necessary to consult a doctor as soon as possible.

Conservative therapy

The treatment regimen is selected individually, taking into account the cause of dyspnea. An important place in the treatment of chronic conditions accompanied by shortness of breath is occupied by lifestyle correction: smoking cessation, regular performance of a special set of physical exercises. With hypoxemia, sessions of oxygen therapy are performed. Shown etiotropic, pathogenetic and symptomatic drug therapy with drugs of the following groups:

  • Bronchodilators . Short-acting beta-adrenergic agonists in the form of inhalers are used to quickly relieve attacks of shortness of breath. Long-term β2-agonists, methylxanthines are used as basic therapy.
  • Expectorants . Medicines are effective in chronic bronchitis, COPD. They stimulate sputum discharge, improve the patency of the bronchial tree. In some cases, expectorants are combined with mucolytics.
  • Antibiotics. Antimicrobial agents are prescribed for acute and chronic inflammatory lesions of the respiratory tract caused by bacterial microflora. When choosing an antibacterial drug, the results of sputum culture are taken into account.
  • Cardiotonics . To reduce shortness of breath in patients suffering from heart disease, cardiac glycosides are used. Pre- and afterload on the myocardium is reduced with the help of peripheral vasodilators and diuretics.
  • Corticosteroids . With a severe degree of respiratory disorders, hormonal drugs are taken on an ongoing basis. In patients with bronchial asthma, inhaled forms of glucocorticoid hormones are effective.
  • Cytostatics . Courses of chemotherapy with anticancer drugs are recommended for patients with malignant neoplasms of the lungs and bronchi. To enhance the effect, drug treatment is supplemented with radiation therapy.

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