Clinical approach to the pre-school child referred with wheeze and cough
The first step is to determine what respiratory noises are being described by the parents. The word “wheeze” is used by parents in the UK at least to describe many different sounds, including the true musical polyphonic noise of diffuse airway narrowing, upper and lower airway crackling noises, and even stridor. The use of a video-questionnaire may help determine this [10, 11]. Asking the parent to record what they hear on their mobile phone may be useful. Many medical professionals cannot be relied on to diagnose wheeze [12], and a healthy scepticism is indicated until the noise has been assessed by a really experienced professional. In the future, hand-held detectors with the data downloaded to a smartphone given to the family may be helpful in resolving this conundrum. If in fact the child has a chronic wet cough, then investigations need to be directed to confirming or otherwise persistent bacterial bronchitis [13] and bronchiectasis [14, 15], both themselves umbrella terms [16], and the underlying cause thereof, which is beyond the scope of this review.
There are five main groups of causes of chronic respiratory symptoms in preschool children (Table 2) [17]. It is important to appreciate the extent of respiratory symptomatology in normal children [18]. Isolated dry cough in an otherwise well child rarely betokens a significant diagnosis. Asthma should not be diagnosed if cough is the sole symptom, with no breathlessness, chest tightness or wheeze; neglect of this rule has led to over-diagnosis and over-treatment of “cough variant asthma”. All normal children cough; intermittent wet cough in association with viral colds, with complete recovery between colds, is normal; and a normal preschool child may have more than ten colds/year with symptoms lasting 2-3 weeks each time [18]. In my practice, this “Nursery School syndrome” is very common; the child is placed early into a childcare facility, by often first-time parents. As a result, the child (and the parents!) gets a succession of viral colds with very few healthy days in between each cold. These do not respond to inhalers or antibiotics; reassurance is what is needed. A prolonged but gradually clearing post-bronchiolitic syndrome of cough and wheeze is also commonly seen in an otherwise normal child. Red flags are progressive symptoms with no symptom free intervals, and a chronic wet cough with no periods of remission.
Although most pre-school children with cough and wheeze are normal or have pre-school asthma, in a few these symptoms betoken a serious disease. The differential diagnosis shows geographical differences, for example compression of the large airways by tuberculous lymph nodes is common in endemic areas. Clues on history and physical examination are shown in Table 3. Most pre-school children with wheeze are managed just on the basis of history and physical examination. If investigations are performed, they should be focussed and address two questions, “can I confirm or exclude an underlying diagnosis?” and “what sort of asthma does this child have?” (This last is addressed later in the review) There is no place for doing many investigations in the hope that something will turn up.