Clinical exam · Respiratory system
Bronchial obstruction syndrome !
- Syndrome
The airways narrow and air is hard to breathe out: long expiration, wheezes and a chest that fills with air.
Updated 2026-11-01
See it in 3D: Main bronchi · Lobar bronchi · Segmental bronchi
What it is
Bronchial obstruction syndrome groups the findings of diffuse narrowing of the intrathoracic airways from bronchospasm, inflammation, mucus or loss of elastic support. Air gets in more easily than it gets out, is trapped and causes hyperinflation. The main causes are asthma and COPD; in infants, bronchiolitis.
Key findings
- A localized, fixed wheeze is not asthma: look for focal obstruction.
- Stridor (upper airway) must not be mistaken for wheezes: it is loudest over the neck and inspiratory.
Pathophysiology
- The bronchial lumen narrows from smooth muscle contraction, wall oedema and inflammation, and mucus.
- On expiration the airways narrow further; air is trapped and the lung hyperinflates.
- Fast air through narrow bronchi makes the walls vibrate and produces wheezes.
- Trapping flattens the diaphragm and raises the work of breathing, which recruits the accessory muscles.
| Inspection | Palpation (fremitus) | Percussion | Auscultation |
|---|---|---|---|
| Asthma attack: tachypnea, accessory muscles, retractions; trachea midline | Reduced fremitus on both sides | Bilateral hyperresonance | Expiratory or biphasic wheezes; prolonged expiration |
| COPD: barrel chest, pursed lips, Hoover sign | Reduced fremitus on both sides | Hyperresonance; low bases | Reduced breath sounds, prolonged expiration, wheezes or rhonchi |
Common causes
- Asthma.
- COPD (chronic bronchitis and emphysema).
- Bronchiolitis in infants.
- Acute bronchitis with bronchospasm, bronchiectasis.
- Heart failure with bronchial oedema ('cardiac asthma').
Tests that confirm it
- Spirometry with a bronchodilator test.
- Peak expiratory flow for asthma follow-up.
- Oxygen saturation and arterial blood gases in a severe attack.
Test yourself
Think of the answer, then tap the question to see it.
Why is expiration prolonged in bronchial obstruction?
Because the airways narrow further on expiration and air leaves slowly, becoming trapped.
What does a silent chest mean in an asthma attack?
Airflow so low it makes no wheezes: severe obstruction with fatigue and risk of respiratory failure.
Which test confirms airflow obstruction?
Spirometry, showing a low ratio of volume exhaled in the first second to forced vital capacity.
Which clinical difference separates asthma from COPD?
Asthma is episodic, triggered and reversible; COPD is progressive, follows cigarette or wood-smoke exposure and is only partly reversible.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- The pleuropulmonary syndromes: the comparison table to know
- Adventitious sounds: crackles, wheezes, rhonchi, stridor and pleural rub
- Pulmonary hyperinflation syndrome (emphysema)
- Respiratory distress and respiratory failure: the signs
- Respiratory rate and breathing patterns
Related conditions
- Asthma
- Chronic obstructive pulmonary disease (COPD)
- Bronchiolitis (RSV)
- Croup (laryngotracheobronchitis)
- Acute bronchitis
Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.
Sources: Asthma: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024); Chronic obstructive pulmonary disease (COPD): MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024); Breath sounds: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024).
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Representative model, for educational purposes only.