Wheeze

Overview

Wheeze is any continuous musical noise, usually expiratory. Stridor is considered an inspiratory wheeze.

Common causes

Localised (partial bronchial obstruction): foreign body, mucus plugging, extrinsic compression.

Generalised: asthma, COPD, bronchiolitis, bronchitis.

Must not miss: bronchial carcinoma (localised); bronchiectasis (generalised, wheeze mostly present during exacerbations).

Pitfall — pulmonary oedema (“cardiac wheeze”): differentiated by being mostly inspiratory, possible pink/frothy sputum, worse lying down and better sitting up, crackles on auscultation, and no relief from bronchodilators.

Wheeze in children

Produced by turbulent airflow in the lower airways — often described by parents as a high-pitched expiratory whistle. In children <1 year, wheeze is commonly due to respiratory infection.

Tracheomalacia/laryngomalacia: consider in healthy infants with noisy breathing since birth, wheeze without infection/respiratory distress, no cough or sleep disturbance. Usually resolves by 12–18 months. Refer to ENT if associated with failure to thrive, increased work of breathing, choking, or gagging.

In older children, wheeze may reflect asthma — but asthma should not be diagnosed if wheeze is only ever present during infections.

Stridor in children

Stridor arises from the upper airway and is usually heard on inspiration. The most common cause is croup (laryngotracheobronchitis).

Differentials: tonsillitis/pharyngitis, epiglottitis (now rare since Hib vaccination), foreign body (e.g. after a choking episode), laryngomalacia (typically resolves by age 1–2), subglottic haemangioma (appears at 6–8 weeks of age, becoming both inspiratory and expiratory).

Persistent stridor warrants specialist referral.