A 6-Year-Old With Wheeze That Does Not Respond: Reassessing the Diagnosis
A 6-year-old girl is brought to the clinic with a 5-month history of episodic cough and wheeze, worse at night and after running. She has been treated with a salbutamol inhaler via spacer as needed and a low-dose inhaled corticosteroid for 4 months, with reported poor response. She has also been given three courses of oral antibiotics for 'chest infections'. Examination: afebrile, respiratory rate 24, oxygen saturation 97% on air, scattered expiratory wheeze bilaterally, no clubbing, no focal crackles. Growth is on the 25th centile for height and 10th for weight, having dropped from the 50th centile over 18 months. Her mother reports frequent loose, bulky stools and that the child tastes 'salty' when kissed. The family recently moved and the inhaler technique has never been observed.
1. Explain how you would distinguish between poorly controlled asthma, poor adherence or technique, and an alternative diagnosis, using the features given.
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The starting point is that 'steroid-resistant asthma' is rare in children, while wrong diagnosis, wrong technique and non-adherence are common - so the first step is to verify the basics before escalating treatment.
Asthma still possible: Episodic wheeze with night-time and exercise triggers is compatible with asthma. Against it: symptoms have been present for 5 months with no sustained response to an adequate dose of inhaled corticosteroid, and there is no atopic history given.
Technique and adherence: Technique has never been observed, and the family has recently moved, which disrupts prescriptions and routines. I would ask for the inhaler and spacer, watch the child use them, check the spacer is the right size and the mask or mouthpiece fits, count actuations, check the prescription refill record, and use a validated adherence question plus a symptom diary. A correct diagnosis treated with an unobserved, poorly used device looks exactly like treatment failure.
Alternative diagnosis: Several features point away from asthma. The faltering growth (height from the 50th to the 25th centile, weight to the 10th) is not explained by asthma. Bulky, loose stools suggest malabsorption. The 'salty' taste on kissing is a classic parental report in cystic fibrosis. Recurrent 'chest infections' requiring three antibiotic courses in 5 months, plus bilateral wheeze without focal signs, fit a bronchiectasis/bronchiolitis picture rather than simple asthma.
So the discriminating move is not a bigger inhaler; it is a sweat chloride test or CF genetic testing, stool elastase and faecal fat, chest imaging, and a review of growth plotted on a chart, alongside observed inhaler technique.
2. Describe the investigations you would order and the safety-netting you would give at this visit.
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First-line investigations:
- Sweat chloride test (or sweat conductivity as a screen where that is the local pathway), with CF genetic testing if borderline - the salty taste, malabsorption and growth failure make cystic fibrosis the leading alternative.
- Stool faecal elastase and faecal fat for pancreatic exocrine insufficiency.
- Chest radiograph, and consider high-resolution CT if bronchiectasis is suspected.
- Spirometry with bronchodilator reversibility if she can perform it reliably at age 6; otherwise document response to a supervised trial.
- Full blood count, inflammatory markers, total IgE and specific IgE to common aeroallergens, and consider a sweat test result review with the CF team if positive.
- Sputum or cough swab for culture if she is productive.
- Growth chart plotted and repeated, with a dietetic referral.
Therapeutic trial with objective measurement: Observe and correct inhaler technique, confirm an age-appropriate spacer, and set a 4-6 week trial with a written symptom and reliever-use diary and a peak flow record if feasible. Escalating the corticosteroid dose without this is unjustified.
Safety-netting: Return immediately for increased work of breathing, inability to complete sentences or feeds, cyanosis, drowsiness, or fever with worsening cough. Do not start antibiotics for every wheeze. Ensure the family knows which symptoms are 'wait for the test result' and which are 'come back today'. Book an early review with the results, and tell them explicitly that we are checking for a condition other than asthma, so they understand why the tests matter.