Clinical presentation and triggering factors
An asthma attack is always characterized by a sudden onset. Most often, the development of the full clinical picture is preceded by certain prodromal signs. The most typical precursor is a marked intensification of a non-productive, completely dry cough.
The leading symptom of a developed attack is expiratory dyspnea — a condition in which it is extremely difficult for the patient to exhale, while inhalation is relatively easy. Dyspnea rapidly progresses and turns into a pronounced sensation of asphyxia.
Among the factors capable of triggering an exacerbation, several main groups are distinguished:
- Contact with an allergen (house dust, animal dander, plant pollen, etc.).
- Physical factors (inhalation of cold air, sharp and irritating odors).
- Physical exertion (strenuous activity, running, heavy lifting).
- Chronobiological features: the occurrence of asphyxia attacks specifically at night is extremely typical for bronchial asthma.
Objective status: appearance and respiratory mechanics
When examining a patient during an attack of asphyxia, their forced posture immediately draws attention. The patient sits, forcefully resting their hands on the edge of the bed, a chair, or their own knees. This posture is necessary to fix the shoulder girdle, which allows accessory muscles to be engaged in the act of breathing.
The mechanics of breathing change significantly:
- There is a pronounced participation of the accessory muscles of the neck, shoulder girdle, and chest in respiratory movements.
- Tachypnea (rapid breathing) develops.
- Exhalation becomes noisy and wheezing, often audible even from a distance (distance rales).
The patient's chest is in a state of constant inspiration — it appears distended and acquires a barrel shape. This is a manifestation of the so-called emphysematous chest shape, arising due to air trapping in the alveoli.
Physical examination findings of the lungs
Medical examination using percussion and auscultation objectively confirms the presence of bronchial obstruction and pulmonary hyperinflation.
Percussion (tapping): A characteristic hyperresonant (box) percussion sound is determined over the entire lung surface. The cause of this sound is the sharply increased airiness of the lung tissue — so-called acute pulmonary emphysema develops, as air leaves the alveoli with difficulty due to bronchial spasm.
Auscultation (listening):
- Respiratory sounds: weakened vesicular breath sounds are heard. The weakening is associated with poor ventilation of the lung tissue against the background of obstruction.
- Respiratory phases: a sharp, pathological prolongation of expiration is revealed.
- Adventitious respiratory sounds: against the background of breathing, a huge number of dry wheezes of various pitches are determined, which are heard particularly clearly precisely during the expiration phase.
Resolution of the attack and interictal period
The relief of the exacerbation is accompanied by clear positive dynamics of symptoms. The following signs indicate the beginning resolution of the attack:
- Sputum appears in the patient, it becomes more liquid and begins to separate much easier with coughing.
- During auscultation, there is a pronounced decrease in the number of dry wheezes in the lungs.
- There is a gradual normalization of the frequency and rhythm of breathing, and the feeling of asphyxia goes away.
In the interictal period, the patient's subjective well-being is usually assessed as good, and they may not present any complaints. However, upon objective examination, some patients may retain clinical signs of pulmonary emphysema for a long time. As a rule, this is observed in patients with a long history of the disease and frequent, severe attacks of asphyxia.
Briefly: answers to topical questions
What pathological elements are detected during microscopic examination of sputum from a patient with bronchial asthma?
Microscopic examination of sputum from a patient with bronchial asthma reveals a specific complex of cellular and structural elements.
- Eosinophils — the cellular basis of allergy, present in large quantities.
- Epithelial cells — can be determined in the form of sheets.
- Curschmann's spirals — spastically formed mucous casts of the small airways.
- Charcot-Leyden crystals — products of crystallization of enzymes released during the breakdown of eosinophils.
What are the symptoms of the prodromal period of an asthma attack?
Symptoms of the prodromal period of a typical bronchial asthma attack:
- Non-productive cough — the attack is often preceded by an increase in dry cough.
By what clinical criteria is status asthmaticus diagnosed?
Status asthmaticus is diagnosed based on signs of extreme acute obstruction and the ineffectiveness of standard bronchodilator therapy.
- Changes in respiratory rhythm — sharp tachypnea with shallow breathing is observed, which is replaced by bradypnea upon exhaustion.
- Paradoxical breathing — discoordination of chest and abdominal movements occurs (thoracoabdominal breathing).
- "Silent lung" syndrome — complete absence of respiratory sounds on auscultation due to generalized bronchospasm and blockage of bronchi by viscous mucus.
Class and exam questions
What type of dyspnea is characteristic of a bronchial asthma attack?
Expiratory dyspnea is typical for the attack. Due to the narrowing of the bronchial lumen, it is extremely difficult for the patient to make a full expiration, while inspiration is relatively free.
Why does the patient adopt a forced sitting position with arms braced during an attack?
Resting hands on knees or the edge of the bed allows for rigid fixation of the shoulder girdle. This is necessary so that the accessory respiratory muscles can most effectively assist in performing respiratory movements.
Why is a hyperresonant (box) sound detected on percussion during an attack?
The hyperresonant percussion sound occurs due to increased airiness of the lung tissue (acute emphysema). Air is trapped in the alveoli due to bronchial obstruction and the inability to perform a full expiration.
How do the characteristics of cough and sputum change as the attack resolves?
Before the attack and at its peak, the cough is dry and non-productive. Upon resolution of the attack, more liquid sputum begins to be coughed up, which separates easily, bringing relief.
What else to study on this topic
- Mechanisms of expiratory dyspnea formation
- Differences between acute and chronic pulmonary emphysema
- Mechanism of dry wheezing formation during auscultation
- The role of accessory muscles in the act of breathing during obstruction
- Chronobiology of the airways and nocturnal asthma attacks
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