PRESCHOOL WHEEZE

Differential diagnosis of wheezing illness in preschool children with suggested investigations

Diagnosis	Key clinical features	Tests
Wheeze in the first year of life	Likely viral or bacterial triggers	Nasopharyngeal aspirate
Episodic (viral) wheeze	Clear history of viral trigger	Thorough history and examination. Exclusion of other likely diagnoses
Multitrigger wheeze	Presence of interval symptoms as well as triggers other than viral infections  Strong family history of atopy	Thorough history and examination. Skin prick testing may be useful in  Multitrigger wheeze
Viral infection	Features of bronchiolitis—coryza, hyperinflation and basal crackles	Nasopharyngeal aspirate for immunofluoresence, PCR or viral culture
Gastro-oesophageal reflux with or without aspiration	Vomiting or poor weight gain. Symptoms such as coughing, mouth, gagging when lying flat raises suspicion	24 hours impedance and pH study. Contrast swallow, bronchoscopy for lipid laden macrophages
Inhaled foreign body	Prior episode of coughing or choking (not always present).  Chronic cough	An inspiratory and expiratory chest radiograph when patient presents acutely can be difficult to perform in preschool age group, a decubitus film may be helpful34; a history of a witnessed choking episode combined with a sudden onset of respiratory symptoms remains the most important indication for bronchoscopy.  To confirm and remove foreign body
Immune deficiency	Wheeze with infections which are severe,  persistent, unusual or recurrent	Immunoglobulins, functional antibodies and T and B cells
Cystic fibrosis	Cough in the first weeks of life. Chronic diarrhoea due to malabsorption leading to faltering growth (if pancreatic insufficient)	Most cases identified are now by newborn screening.  Sweat test
Primary ciliary dyskinesia	Chronically discharging ears and persistent and/or early-onset (first few weeks of life) rhinorrhoea	Chest radiograph to look for dextrocardia (present in 50%).  Ciliary studies
Tracheomalacia/bronchomalacia	History of trachea-oesophageal atresia and oesophageal atresia, harsh, monophonic expiratory noise or noisy breathing	Flexible bronchoscopy
Cardiac abnormality  (particularly those causing left to right shunt)	May be evidence of biventricular failure  (tachycardia, hepatomegaly and  Pulmonary crackles).	Chest radiograph, ECG and echocardiogram
Postinfectious obliterative  bronchiolitis	Previous adenovirus35 (most common antecedent) infection, prolonged oxygen requirement, tachypnoea and crackles	Inspiratory and expiratory images on high-resolution c