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PE28.1-5 | Allergy and Asthma — PBL Case
CLINICAL SETTING
A government district hospital paediatric outpatient department in coastal Karnataka, India. It is July — peak monsoon season. The waiting hall is crowded with children presenting with respiratory complaints. You are a final-year medical student attached to the paediatric unit. The consultant asks you to clerk the next patient and present your findings.
Trigger 1: The Wheezing Child
Rohan, a 9-year-old boy (weight 26 kg), is brought by his grandmother because he 'wheezes every time it rains' and has been unable to play in the school sports day for two consecutive years due to breathlessness. He coughs every night, waking 3–4 times a week. Over the past 2 years he has been admitted twice to the local primary health centre with acute breathlessness and once required a 3-day hospitalisation. His grandmother gives him 'cough syrup' (containing chlorpheniramine + dextromethorphan) from a local pharmacy whenever symptoms worsen. He also has a 1-year history of sneezing, bilateral nasal blockage, and clear watery discharge 'every single day'. He attends school but is frequently drowsy in class — the grandmother attributes this to 'weak health'. Past history: atopic dermatitis as an infant. Family history: mother has allergic rhinitis; father has no respiratory illness. No pets at home but there are dampness and mould patches in two rooms of their rented house. He takes no regular medication.
DISCUSSION POINTS
- What is the most likely diagnosis and what clinical features support it? Use GINA criteria to classify the severity of his asthma.
- What is the likely cause of his daytime drowsiness in school? How does this relate to his grandmother's self-medication choice?
- What is the ARIA classification of his rhinitis (frequency AND severity axes)? How does allergic rhinitis relate to asthma in pathophysiology and management?
- List the risk factors in Rohan's history and environment that are likely triggering and perpetuating his asthma and rhinitis.
Click to reveal Trigger 2: Examination and Investigations (discuss previous trigger first!)
Trigger 2: Examination and Investigations
On examination: RR 26/min, mild subcostal indrawing, bilateral expiratory wheeze on auscultation, Harrison's sulcus bilaterally (suggesting chronic air trapping). No cyanosis, no clubbing. Nasal mucosa pale and boggy, bilateral inferior turbinate hypertrophy. No nasal polyps. Conjunctival injection with chemosis. Skin: two patches of lichenified eczema on the antecubital fossae. Weight and height are on the 25th centile. Investigations requested by the consultant: - Spirometry (cooperative effort): FEV1 68% predicted, FVC 84% predicted, FEV1/FVC 0.75; post-salbutamol 400 mcg: FEV1 82% predicted - Peak expiratory flow rate (PEFR): diurnal variability 28% over 7-day diary - Skin-prick tests: strongly positive (3+ wheal) for house dust mite (Dermatophagoides pteronyssinus), cockroach allergen; weakly positive (1+) for Alternaria (mould) - Total serum IgE: 480 IU/mL (normal <100 IU/mL) - CBC: eosinophilia 8% (absolute 600 cells/µL) - Chest X-ray: hyperinflation, no infiltrates, no cardiomegaly
DISCUSSION POINTS
- Interpret the spirometry result: classify the pattern, calculate the bronchodilator reversibility percentage, and state whether it is significant. What does PEFR diurnal variability ≥20% indicate?
- What does the skin-prick test sensitisation profile tell you about Rohan's asthma triggers, and how does it relate to his home environment (dampness, mould patches)?
- Harrison's sulcus is present. What does this physical sign indicate about the chronicity and severity of his airway disease?
- The eosinophilia and elevated IgE — what is their pathophysiological significance in allergic asthma? Would this influence your choice of therapy at any GINA step?
Click to reveal Trigger 3: Management Decision Point (discuss previous trigger first!)
Trigger 3: Management Decision Point
The consultant asks you to prescribe a complete management plan. Rohan's grandmother is worried about 'steroid side effects' from the inhalers she has heard about from neighbours. She says she prefers the 'cough syrup' because it 'at least makes him sleep and stops the cough'. The hospital pharmacist informs you that the following are available: salbutamol pMDI + large-volume spacer with paediatric mask, budesonide pMDI 100 mcg/puff, montelukast 5 mg (paediatric chewable), cetirizine syrup 5 mg/5 mL, mometasone nasal spray 50 mcg/spray, and oral prednisolone 5 mg tablets.
DISCUSSION POINTS
- Prescribe a complete GINA-stepwise controller and rescue plan for Rohan, with all doses in mg/kg or mcg/day (weight 26 kg). Justify the GINA step chosen.
- How would you address the grandmother's concern about inhaled corticosteroid side effects? What are the actual risks of growth suppression and adrenal suppression with low-dose ICS, and how can they be mitigated?
- Prescribe treatment for the allergic rhinitis (ARIA-guided), including the choice of antihistamine. Explain why the current cough syrup (chlorpheniramine + dextromethorphan) is inappropriate for this child.
- Demonstrate (describe step-by-step) the correct technique for using salbutamol pMDI + spacer with paediatric mask in a 9-year-old. What specific errors must be avoided?
Click to reveal Trigger 4: Follow-Up and Prevention (discuss previous trigger first!)
Trigger 4: Follow-Up and Prevention
Six weeks later, Rohan's mother brings him for review. He is now on budesonide 200 mcg/day (2 puffs of 100 mcg/puff once daily via spacer) and salbutamol as needed. He has had no nighttime waking for 3 weeks, daytime symptoms are 2 days/week, and he played in an inter-school cricket match without stopping. His grandmother stopped the cough syrup. However, his mother has a new concern: she read online that children on 'steroid inhalers' need to be tested for 'weak bones'. She also mentions that the school sports teacher recommended Rohan should be 'excused from all exercise permanently'.
DISCUSSION POINTS
- Reassess Rohan's asthma control using GINA control criteria (well-controlled / partly controlled / uncontrolled). Is a step-up, step-down, or maintenance appropriate at this visit?
- How would you counsel Rohan's mother about bone density monitoring and other monitoring requirements for long-term ICS use? At what ICS dose thresholds does the risk of systemic effects increase?
- Is the school sports teacher's advice correct? Prescribe a specific evidence-based plan for managing Rohan's exercise-induced bronchoconstriction to allow him to continue sport.
- What environmental control measures should the family implement in their dampness-affected home to reduce house dust mite and mould allergen load? Be specific and practical.
Group Task Assignments
Group 1: Collaborative Task
Group 2: Collaborative Task
Group 3: Collaborative Task
Learning Issues
Research these questions and bring your findings to the discussion.
- [PE28.1] What are the etio-pathogenesis, ARIA classification, clinical features, and stepwise pharmacological management of allergic rhinitis in children, and how does untreated AR affect asthma control?
- [PE28.2] What are the etio-pathogenesis, GINA classification (severity and control), clinical types (atopic vs non-atopic, EIB), and prevention strategies for childhood asthma, and what is the biphasic (early and late phase) allergic response?
- [PE28.3] How do you develop an evidence-based, GINA-stepwise treatment plan for childhood asthma (controller + rescue), with weight-based dosing, and how do you manage acute exacerbations including the role of MgSO₄ in severe asthma?
- [PE28.4] What are the indications for PFT/spirometry in a child, how do you interpret FEV1/FVC ratio, reversibility (≥12% threshold), and PEFR diurnal variability, and what are the age limitations of standard spirometry?
- [PE28.5] What are the correct technique, flow rate (6–8 L/min), fill volume, and position for paediatric jet nebulisation, and how should a medical student observe and record these parameters as a clinical skill?