Wheezing
Basics
Basics
Basics
Description
Description
- Result of turbulent airflow:
- High-pitched sound with dominant frequency at 400 Hz:
- Gas flowing through constricted airways analogous to a vibrating reed
- Resonant vibration of the bronchial walls when airflow velocity reaches critical values
- Caused by airway narrowing between 2–5 mm:
- Wheezing is very low pitched with airway diameters of 5 mm
- Airways of <2 mm are unable to transmit sound because the energy is lost as friction heat
- Airway narrowing is caused by a combination of ≥1 of the following:
- Constriction (as with reactive airway disease)
- Peribronchial interstitial edema
- Inflammation
- Obstruction
Etiology
Etiology
- Pulmonary (small airway):
- Asthma
- Acute respiratory distress syndrome
- Anaphylaxis
- Aspiration pneumonia:
- Wheezing occurs early in the disease due to intense bronchospasm following the event
- Byssinosis:
- Occupational lung disease of textile workers exposed to cotton dust
- Drugs:
- Can precipitate angioedema or allergic reaction
- ACE inhibitors
- β-Blockers
- Aspirin and NSAIDs
- Forced exhalation in normal patients
- Hyperventilation
- Chronic obstructive pulmonary disease
- Chronic cor pulmonale
- Chemical pneumonitis
- Carcinoid tumors
- Paroxysmal nocturnal dyspnea
- Pulmonary edema
- Pulmonary embolism:
- Rarely associated with wheezing
- Focal
- Pneumonia
- Sleep apnea
- Pulmonary (large airway):
- Vocal cord dysfunction (paralysis, paradoxical movement)
- Foreign body
- Epiglottitis:
- Wheezing associated with stridor in 10% of cases
- Diphtheria
- Smoke inhalation
- Bronchial tumor
- Tracheal tumor
Pediatric Considerations
- Viral bronchiolitis in patients <3 yr of age
- Asthma
- Infection:
- Epiglottitis
- Gastroesophageal reflux
- Foreign-body aspiration
- Congenital abnormalities:
- Tracheomalacia
- Tracheal stenosis
- Vascular ring
- Cystic fibrosis
- Cardiac disease
- Psychogenic respiratory distress
- Paradoxical vocal cord dysfunction characterized by abnormal vocal cord adduction during inspiration
There's more to see -- the rest of this topic is available only to subscribers.
© 2000–2025 Unbound Medicine, Inc. All rights reserved