Differentials

Pertussis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Paroxysmal cough, inspiratory whooping, post-tussive vomiting, and, in infants, cyanosis or apnoea. Symptoms occur in three phases: catarrhal, paroxysmal, and convalescent.[43]

INVESTIGATIONS

Definitive diagnosis is based on culture of Bordetella pertussis from a posterior nasopharyngeal swab or nasopharyngeal aspirate.[43] In practice, rapid testing with a polymerase chain reaction (PCR) assay is often used.[44]

Croup

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Barking cough and a hoarse cry or voice, which may be accompanied by inspiratory stridor.[45][46]​​​ Typically affects children aged 6 months to 3 years.[47]

INVESTIGATIONS

Usually a clinical diagnosis.

Bronchiolitis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Primarily a disease of infancy (rare in children >1 year old); usually starts with upper respiratory tract symptoms (e.g., rhinitis and cough); fever, if present, usually low-grade. Cough then increases in severity, and lower respiratory tract symptoms develop (e.g., wheeze, retractions, tachypnoea).[48]

INVESTIGATIONS

Usually a clinical diagnosis.

Viral-induced wheeze

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Most commonly presents in children aged 1-5 years; there may be a history of intermittent wheezing associated with viral infection, with no symptoms between episodes; fever, if present, usually low-grade; symptoms respond to bronchodilator therapy (short-acting beta-agonist).[49]

INVESTIGATIONS

Usually a clinical diagnosis.

Foreign body aspiration (FBA)

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

History of a choking episode with sudden onset of respiratory distress associated with coughing, gagging, or stridor. Unilateral decreased breath sounds and/or unilateral wheezing.[50]

INVESTIGATIONS

Chest x-ray: visualisation of radio-opaque foreign body or indirect signs if the foreign body is radiolucent (e.g., atelectasis, air trapping, pneumomediastinum).

Bronchoscopy is the standard of care for diagnosis and treatment of FBA.

Asthma exacerbation

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

History of asthma and/or atopic disease (e.g., boggy mucous membranes); nocturnal cough, particularly if associated with wheeze; family history of asthma or atopy; may be triggered by physical exertion or airway irritants; fever and other signs of infection absent (unless exacerbation is virally triggered).[8]

INVESTIGATIONS

Bronchoconstriction responds to short-acting beta-2 agonist; no signs of infiltration on chest x-ray (normal or may show hyperinflation).[51]

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