Clinical presentation variants
Impaired bronchial patency can develop at varying rates, which determines patient management tactics. There are two main variants of the clinical course:
- Acute course. Accompanied by prominent signs of acute respiratory failure (ARF). This condition poses an immediate threat to life and requires emergency medical care.
- Chronic course. Characterized by a prolonged development. The leading symptom is a severe cough, which is more often productive (with sputum production), but sometimes non-productive. Long-standing chronic obstruction naturally leads to the development of pulmonary emphysema.
Etiology and pathogenesis of obstruction
Topographically, bronchial obstruction is associated with primary involvement of the small bronchi. The mechanisms leading to the narrowing of their lumen are divided into primary (associated with inflammation and allergy) and additional mechanisms.
Primary mechanisms:
- A combination of inflammation and pronounced edema of the bronchial mucosa (a classic example is chronic bronchitis).
- A combination of bronchospasm and mucosal edema (observed in bronchial asthma).
Additional mechanisms:
- Peribronchial fibrosis. A diffuse process in which proliferated connective tissue compresses the bronchi from the outside.
- Mechanical compression in emphysema (valvular mechanism). Due to the loss of the elastic framework of the small bronchi during expiration, when the pressure inside the alveoli increases, the bronchial pathways are compressed. Air becomes "trapped" in the alveoli.
Clinical manifestations
Taking a medical history helps identify two key symptoms of the syndrome:
- Expiratory dyspnea. The patient experiences obvious difficulty specifically when trying to exhale.
- Cough. In a prolonged (chronic) course of the disease, cough plays a dual role. On the one hand, it is a classic symptom of bronchial tree damage. On the other hand, persistent coughing itself acts as a pathogenetic factor: sharp fluctuations in intrathoracic pressure during cough shocks exacerbate the structural changes in the pulmonary parenchyma, directly contributing to the development of emphysema.
Objective diagnostics
The diagnosis of bronchoobstructive syndrome is confirmed by physical and instrumental methods.
Auscultatory findings:
- Breath sounds: harsh vesicular breathing is auscultated.
- Phase ratio: the key marker of obstruction is the prolongation of the expiratory phase. Exhalation becomes prolonged and coarse.
- Adventitious respiratory sounds: wheezes are detected. Their pitch and localization allow the physician to assess not only the degree of narrowing but also the level of bronchial involvement.
- "Silent chest" phenomenon: a formidable sign of extreme acute obstruction. The bronchial lumen is blocked so severely that airflow ceases, and breath sounds disappear completely.
Instrumental assessment (PFT): Spirometry and pneumotachometry are used to objectify the disorders. In obstruction, the following are registered:
- Decrease in the Tiffeneau index (the value drops below 60%).
- Decrease in forced expiratory volume in the first second (FEV1).
- Decrease in expiratory airflow velocity parameters (according to pneumotachometry).
Instrumental and radiological examinations also reveal hyperinflation syndrome, closely associated with the development of pulmonary emphysema.
Briefly: answers to topical questions
Which nosological forms most frequently cause bronchoobstructive syndrome?
Bronchoobstructive syndrome is associated with primary involvement of the small bronchi.
The nosological forms and conditions indicated in the sources include:
- Chronic obstructive bronchitis — an example of a disease with obstruction of the small bronchi.
- Bronchial asthma — impaired patency is associated with bronchospasm and mucosal edema.
- Pulmonary emphysema — mechanical compression of the small bronchi via a valvular mechanism is possible during expiration.
- Chronic obstructive pulmonary disease — characterized by the development of bronchoobstructive syndrome with partially reversible and irreversible airflow limitation.
In addition, bronchoobstructive syndrome frequently develops as a complication of the classic form of bronchopulmonary dysplasia in premature infants.
What symptoms are detected during the physical examination of a patient with bronchoobstructive syndrome?
Examination of a patient with bronchoobstructive syndrome may reveal signs of respiratory failure and lung hyperinflation.
Main signs indicated in the sources:
- Chest — barrel-shaped; in COPD, there may be an increase in the anteroposterior diameter, a more horizontal direction of the ribs, and smoothing or bulging of the supraclavicular fossae.
- Respiration — participation of accessory muscles in the act of breathing; expiratory dyspnea requires additional effort during exhalation.
- Skin — with the progression of COPD with bronchial obstruction and severe respiratory failure, diffuse cyanosis with a grayish tint is possible.
- In severe exacerbation of bronchial asthma, noisy breathing with distant wheezes, orthopnea, tachypnea, diffuse cyanosis, and participation of accessory muscles may be detected.
With concomitant bronchiectasis or chronic purulent bronchitis, clubbing of fingers and watch-glass nails may be detected.
How to determine the level of bronchial involvement by the pitch of wheezes?
The pitch of wheezes upon auscultation directly depends on the caliber of the affected airway divisions.
Diagnostics of the level of involvement:
- High-pitched wheezes (sibilant) — indicate narrowing of distal small bronchi, which may be caused by viscous sputum, mucosal edema, or spasm.
- Low-pitched wheezes (sonorous, buzzing, and humming) — indicate the accumulation of viscous sputum in the proximal large and medium bronchi.
Evaluating these features allows the physician to determine not only the level of bronchial tree involvement but also the degree of its narrowing.
Class and exam questions
How to differentiate dyspnea in broncho-obstructive syndrome?
Expiratory dyspnea is typical for this syndrome. The patient finds it difficult to perform a full exhalation, whereas inspiration may remain relatively free.
What is the check-valve mechanism in emphysema?
This is a pathological process in which increased pressure in the alveoli during expiration compresses the small bronchi, which lack elastic support. Because of this, air cannot escape outward.
What does the appearance of the "silent lung" phenomenon indicate?
This is a sign of a critical condition in acute bronchial obstruction. The bronchi are narrowed so severely that ventilation ceases, and no breath sounds are auscultated.
What else to study on this topic
- Pathogenesis of the valvular mechanism in pulmonary emphysema
- The role of inflammation and edema in chronic bronchitis
- Mechanisms of bronchospasm in bronchial asthma
- Interpretation of the flow-volume loop in spirometry
- Pulmonary hyperinflation syndrome: clinical and instrumental correlations
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