Dyspnea

Evaluation of complaints of dyspnea should begin with monitoring the respiratory movements of the patient at rest and after performing physical exertion.

The definition of the concept of shortness of breath causes controversy and ambiguous interpretations. Shortness of breath is defined as a feeling of insufficient breathing, difficulty breathing, lack of air, etc. It is important to emphasize that dyspnea is a purely subjective phenomenon and can not be defined in terms used in assessing blood gases or ventilator disorders. Dyspnea often occurs in the framework of neurotic disorders, it can be an integral part of the syndrome of hyperventilation or precede its development. Lack of air is a central phenomenon in the clinical manifestations of psychogenic dyspnea. The degree of expression can be different: with an increase in the feeling of shortness of breath, there are hyperventilation manifestations, which bring to the clinical picture numerous symptoms. Shortness of breath, or dyspnea, is the most frequent, leading symptom of panic attacks. According to preliminary studies, in patients with various vegetative disorders, unpleasant sensations in the respiratory tract, respiratory discomfort, including dyspnea, occur in more than 80% of cases.

The American Thoracic Society proposed the following definition: dyspnoea is a concept that characterizes the subjective experience of respiratory discomfort "and includes qualitatively different sensations that vary in intensity. This subjective experience represents the result of the interaction of physiological, psychological, social and environmental factors and can lead to secondary physiological and behavioral responses.

[1], [2], [3], [4], [5]

The most common causes of dyspnoea

1. Diseases of the lungs and respiratory tract
   • Chronic bronchitis and emphysema
   • Bronchial asthma
   • Bronchoectatic disease
2. Diseases of the lung parenchyma
   • Respiratory failure of any etiology
   • Pneumonia
   • Tumors of the lungs
   • Alveolitı
   • Sarcoidosis (I, II stage)
   • Condition after extensive pulmonectomy
3. Other states
   • Pneumothorax
   • Embolism of the pulmonary artery
4. Diseases of the cardiovascular system
   • Heart failure of any etiology
   • IHD: angina pectoris, myocardial infarction
   • Arrhythmias of various etiologies
   • Myocarditis
   • Heart defects.
5. Pathology of the chest
   • Pleural effusion
   • Neuromuscular diseases (including those accompanied by paresis or paralysis of the diaphragm)
6. Anemia
7. Pronounced obesity
8. Psychogenic factors

How does dyspnea develop?

Dyspnea  (dyspnoe)  -  violation frequency rate and depth of breathing, accompanied by an increase in the work of respiratory muscles and is generally subjective sensations lack of air or breathing difficulties, often - cyanosis (with lung diseases normally "warm" due to secondary compensatory erythrocytosis and dilation of small blood vessels because of hypercapnia). The objective sign of shortness of breath is the rapidity of breathing (more than 18 per minute). Often, shortness of breath is felt as a feeling of tightness in the chest during inspiration, the impossibility of a deep breath and complete release from the air during exhalation.

At the heart of any shortness of breath is the excessive or pathological activity of the respiratory center. It arises as a result of irritation with a recipe located in the airways, the lungs themselves, the respiratory muscles. Nevertheless, in general, the causes of unpleasant subjective sensations during dyspnea remain unclear.

In patients with lung diseases, dyspnea is closely related to the violation of the respiratory mechanism. At the same time, a large inspiratory effort, for example, with an increase in the rigidity of the bronchi and lungs (difficulty in bronchial patency, pulmonary fibrosis) or with a large chest (emphysema, asthma attack), leads to an increase in the work of the respiratory muscles (in some cases with the inclusion of additional musculature).

In diseases of the respiratory system, dyspnea has a different origin. It can be associated with an obstruction to the normal passage of air in the airways. Another cause may be a decrease in the respiratory surface of the lungs (compression in the accumulation of fluid or air in the pleural cavity, switching off part of the lung from gas exchange in inflammatory infiltrates, atelectasis, infarction, tumor, thoracoplasty, resection of the lung, partial loss of lung plasticity). All this leads to a reduction in ventilation, a decrease in the VL. As a result, the concentration of carbon dioxide in the blood increases, acidosis develops. With interstitial pneumonia, pulmonary edema, the situation may be aggravated by the appearance of the alveolar-capillary block.

In heart diseases, shortness of breath is a manifestation of insufficient blood circulation and is due to a number of factors that cause excitation of the respiratory center. Dyspnoea occurs when there is a disturbance in gas exchange, accumulation of under-oxidized products in the blood. This leads to increased and deepening of breathing. Especially severe violations of gas exchange occur when blood is stagnant in a small circle of circulation. In acute left ventricular failure initially develops an interstitial edema, and then an alveolar edema.

Three pathophysiological mechanisms of respiratory failure can be distinguished.

1. Hyperventilation with decreased arterial oxygen saturation (hypoxemia) or supersaturation with carbon dioxide (hypercapnia) during physical exertion, staying at high altitudes, heart failure, and also with increased oxygen demand for thyrotoxicosis, fever.
2. Relative hyperventilation with a decrease in the respiratory surface of the lungs.
3. Mechanical disturbances of ventilation (stenosis of the upper respiratory tract, bronchial obstruction, emphysema, diaphragmatic nerve paresis and other injuries of the respiratory musculature, heart failure, kyphoscoliosis).

On the bulbar center, there is an increase in the voltage of carbon dioxide, and a decrease in the oxygen content, and a shift of the pH to the acid side. Accumulation of carbon dioxide is of predominant importance. With prolonged hypoxemia, the mechanism of the effect of oxygen on the carotid sinus is included. In addition to chemical factors, the volume of breathing regulates reflex effects from the lungs, pleura, diaphragm and other muscles.

Ultimately, a feeling of lack of air can be formed by the following mechanisms: an increase in the sense of respiratory effort, stimulation of the irrational receptors of the airways, hypoxemia, hypercapnia, dynamic compression of the respiratory tract, afferent imbalance, stimulation of the baroreceptors of the vessels of the lungs and the right atrium.

Epidemiology

In the US, more than 17 million patients a year seek medical help in connection with shortness of breath The prevalence of dyspnea in the general population is different and depends on age. In the population of 37-70 years, it varies from 6 to 27%. Dyspnoea in children due to pathophysiological features of childhood can reach 34%. During the first months of life, shortness of breath is very rare. After two months of life, the incidence of first-appearing dyspnea significantly increases, reaching a maximum between the second and fifth months of life, and in most cases, shortness of breath during the first three months of life is associated with a respiratory syncytial virus. In epidemiological studies of children, it is estimated that by the age of six, shortness of breath remains in about 40% of children who have suffered from it in the first three years of life.

[6], [7], [8], [9], [10], [11], [12], [13]

Types of dyspnea

Shortness of breath can be subjective and objective: it is also possible to combine them. Subjective dyspnea is understood as a subjective sensation of a lack of air to patients with breathing. Objective dyspnea is determined by objective methods of investigation and is characterized by a change in the frequency, depth or rhythm of breathing, as well as the duration of inspiration or expiration.

The variant of a dyspnea or short wind can be assumed already at studying of the anamnesis; Physical examination provides important additional information. Distinguish inspiratory (difficulty inhaling), expiratory (difficulty exhaling) and mixed dyspnoea.

• Inspiratory dyspnea occurs when there are obstacles to air flow into the trachea and large bronchi (swelling of the vocal cords, tumors, foreign body in the lumen of the bronchi).
• Expiratory dyspnea is most common for emphysema of the lungs or bronchospasm (for example, with an attack of bronchial asthma). In emphysema, dyspnea is associated with the so-called expiratory collapse of the bronchi: as during inspiration, the pressure of the lung parenchyma (with a large residual volume of air) on the bronchial tubes of medium and small caliber is much less than on exhalation, if the rigidity of the bronchial tissue skeleton is insufficient, which is very typical for emphysema of the lungs, they subside, this leads to difficulty in removing air from the alveolar parts of the lungs. With bronchospasm, it is difficult to remove air from the alveoli, which is associated with an increase in the exhalation of air pressure in already narrowed (spasmodic) bronchi of medium and small caliber.
• Mixed variant of dyspnea is observed most often; it is characteristic for chronic respiratory and chronic heart failure, which develops in the late stages of respiratory and circulatory diseases.

A special variant of shortness of breath, called suffocation, is specially distinguished, - an attack of extreme dyspnea, when all parameters of respiration (frequency, rhythm, depth) are violated to the maximum extent. Most often, such dyspnea accompanies an attack of bronchial asthma and acute left ventricular failure (cardiac asthma).

It is necessary to name one more kind of disturbances of breath - its temporary stop (apnea), which is sometimes observed in obese people usually during sleep, which is accompanied by a strong snoring (Pickwick syndrome). This condition occurs usually in the absence of primary lung disease and is associated with a deep hypoventilation of the alveoli due to extremely pronounced obesity.

According to the frequency of breathing, shortness of breath is distinguished with an increase in the respiratory rate (tichypnea), with a normal respiratory rate and with a decrease in the respiratory rate (bradypnoea).

Shortness of breath in the lying position is called orthopnea (usually associated with venous pulmonary congestion). Platypnea - dyspnoea in a standing or sitting position (more often associated with intracardial and intrapulmonary shunts and lesion of the muscles of the chest); trepposnoe - in a position lying on its side (usually occurs with congestive heart failure).

Dyspnoea may be physiological (with increased physical exertion) and pathological (with diseases and poisoning with certain poisons).

The severity of dyspnea in chronic diseases is assessed by the International Differential Disease Scale (Medical Research Count ll Dyspnea Scale).

How is dyspnea recognized?

The data of the anamnesis for various diseases reflect primarily the underlying pathology.

Dyspnea with heart disease reflects a lack of blood circulation, so by its severity, one can judge the degree of insufficiency. So in the initial stages of heart failure, shortness of breath occurs only with physical exertion, climbing stairs or uphill, with fast walking. Often the earliest sign of advancing left ventricular failure is attacks of excruciating cough at night. With the progression of the disease, dyspnea occurs even with minimal physical activity (during conversation, after eating, while walking). In severe cases, there is constant shortness of breath at rest. In the most severe cases, typical night attacks of paroxysmal asphyxiation develop, which can result in pulmonary edema. The questionnaire usually identifies the relationship of these seizures with physical effort. They can occur directly during exercise or a few hours after the end. Depending on the severity of the condition, the resulting orthopnea can last from several hours to several days. As a rule, simultaneously with orthopnea there is pain in the region of the heart. In patients with aortic insufficiency, shortness of breath is sometimes accompanied by profuse sweating (sweat trickles down). In patients with heart failure, a history of cardiovascular pathology (ischemic heart disease, prolonged or high arterial hypertension, heart defects) is usually observed.

Dyspnea with emphysema also occurs first with considerable physical exertion, then gradually progresses. Sometimes it is regarded as hearty and treated with cardiac glycosides for a long time, as a rule, unsuccessfully. The data of the anamnesis with emphysema can talk about the presence of chronic bronchitis, prolonged smoking experience, prolonged contact with pollutants, damaging inhalation professional factors. Primary emphysema is more often observed in men in middle and young age. With a second emphysema, more characteristic of the elderly, a pulmonary heart develops. In conjunction with the survey data, diagnosis usually does not cause difficulties.

In obstructive bronchitis, in most cases it is also possible to detect prolonged smoking experience or contact with airway-damaging agents, as well as recurrent exacerbations of bronchitis against respiratory infection.

Shortness of breath with bronchial asthma is usually combined with attacks of suffocation and cough (anamnestic features are presented in the articles "Cough", "Choking" and "Bronchial asthma"). The feeling of shortness of breath in patients with asthma usually corresponds to the degree of bronchial obstruction. In patients with obstructive bronchitis there is no correlation between breathlessness and the magnitude of FEV1. In elderly patients, asthma often comes to the fore not with attacks, but prolonged dyspnea, similar to that in obstructive bronchitis, emphysema of the lungs. Differential diagnostic signs of bronchial asthma and chronic obstructive bronchitis are presented in the article "Bronchial asthma".

For bronchiectasis is characterized by a large number of purulent sputum, a frequent connection with a bacterial infection.

Obliterating bronchiolitis develops at a young age, usually on contact with acid and alkali vapors. Clear communication with smoking is not present. Sometimes rheumatoid arthritis is found.

With the oncological lesion of the trachea, the main symptom is intermittent dyspnoea, disguised as asthma attacks. At the same time, the accompanying symptoms, such as coughing, hemoptysis, fever and weight loss. These same symptoms can also occur in other tumor lesions of the respiratory tract.

Tracheobronchomegaly (congenital pathology) manifests itself throughout the life of the patient: in addition to dyspnea, this is a very loud, persistent cough, complications in the form of pneumonia, bronchitis, bronchiectasis.

Psychogenic dyspnea usually occurs in patients under the age of 40 and is often combined with neuroses. It often has an intermittent nature, is not associated with physical stress, can be accompanied by excitation, dizziness, impaired concentration, palpitation, fatigue.

Physical examination

Auscultatory in patients with bronchial asthma dry rales of the expiratory (sometimes inspiratory) type are listened. They can be either high, treble or low, bass, different timbre and loudness. If sputum accumulates sputum, then the auscultatory picture (the number and timbre of wheezing) can change after coughing. In the phase of remission, changes during physical examination may not be detected.

Emphysema is characterized by: barrel-shaped chest, inspiration in the position of the chest, dome-shaped protrusions in the supraclavicular fossa, limited chest excursion, box percussion sound, low diaphragm mobility, reduction of the boundaries of absolute cardiac dullness (due to the covering of the heart with swollen lungs), weak heart grafts and weakened breathing with auscultation of the lungs.

With fibrosing alveolitis, sometimes a change in the fingers and pops in the form of "drum sticks" and "watch glasses" is revealed.

Similar clinical signs can be found in systemic pathology with lung damage.

With bronchiectasis, the patient can identify "drum sticks", auscultatory - rough damp various rales.

In a patient with heart failure during physical examination, signs of the main cardiac pathology appear, and in the case of auscultation of the lungs, wheezing occurs in the lower parts.

When stenosis of large respiratory tract is determined by the stridor breathing.

Laboratory research

Dyspnea is accompanied by laboratory changes corresponding to these diseases. So, if dyspnea develops against anemia, then a decrease in hematocrit and other signs of a particular type of anemia is revealed. If this is an infectious process, it is possible to detect leukocytosis with a shift of the formula to the left, an increase in ESR. Tumor process can also be accompanied by an increase in ESR, the appearance of anemia. With systemic lesions, the relevant signs of an autoimmune process are revealed, the level of proteins of the acute phase of inflammation increases. Thyrotoxicosis manifests an increased level of thyroid hormones, autoantibodies to thyroglobulin and thyroid peroxidase in autoimmune thyroiditis.

With psychogenic dyspnoea, laboratory parameters correspond to the norm,

Instrumental research

Bronchial asthma may not be accompanied by any radiographic changes. In the phase of acute attack, the presence of emphysema (increased transparency of pulmonary fields and restriction of diaphragm mobility) is revealed, and in case of prolonged course (more often with non-atopic variants or with concomitant bronchitis) - phenomena of pneumosclerosis and emphysema. Spirographically reveal violations of pulmonary ventilation according to the obstructive type, as in chronic obstructive bronchitis. The difference between asthma and the reversibility of bronchial obstruction

X-ray signs of emphysema low diaphragm standing, reduction of its mobility, increased transparency of pulmonary fields; a symptom of emphysema in men is a significant decrease in the distance from the lower edge of the thyroid cartilage to the sternum arm.

With broichoectas on the radiograph or according to computed tomography, the bronchial dilatation and the thickening of their walls are revealed.

On the roentgenogram with heart failure, the expansion of the contours of the heart, stagnation (up to the pulmonary edema), spirogram - restrictive pulmonary ventilation. Various abnormalities (rhythm disturbance, conduction, signs of hypertrophy and disturbance of blood supply to the myocardium) can be detected on the ECG. Heart defects will be reflected in EchoCG and FCG.

With tumor processes, the correct diagnosis is assisted by X-ray findings and bronchoscopy.

In patients with psychogenic dyspnea, an instrumental examination of pathology does not reveal; spirogram normal or with signs of hyperventilation.

Indications for specialist consultation

Bronchial asthma, edema of Quincke serve as an indication for the consultation of an allergist.

In acute bronchiolitis, dust bronchitis, pulmonary emphysema, pleural lesions, interstitial pulmonary diseases, cystic fibrosis, consultation of a pulmonologist is shown, with chronic obstructive bronchitis - a pulmonologist and an allergist.

The appearance of narrow-chested breathing, suspicion of laryngeal stenosis, pharyngeal abscess, foreign body require consultation of an otorhinolaryngologist.

If there is a suspicion of systemic pathology, the consultation of a rheumatologist, a tumor oncologist, tuberculosis and sarcoidosis - phthisiatric, anemia - a hematologist, and dyspnoea of a central origin, a neuropathologist are indicated. A psychiatrist consultation is indicated for psychogenic dyspnea.