What are the GINA (Global Initiative for Asthma) recommendations for diagnosing asthma in children?

GINA Recommendations for Diagnosis of Asthma in Children

According to the 2020 GINA strategy document, diagnosis of asthma in children requires objective testing with spirometry and bronchodilator reversibility (BDR) testing or 2 weeks of twice-daily peak expiratory flow rate (PEFR) variability measurements. 1

Diagnostic Approach for Children 5-16 Years

Key Diagnostic Tests

1. Spirometry with BDR testing:

   • First-line objective test
   • Abnormal results: FEV1 or FEV1/FVC less than lower limit of normal (LLN) and/or <80% predicted
   • Normal spirometry does not exclude asthma

2. Exhaled Nitric Oxide Fraction (FeNO):

   • Should ideally be performed before spirometry
   • Cut-off of 25 ppb is recommended (lower than previous 35 ppb recommendation)

3. Peak Expiratory Flow Rate (PEFR) Variability:

   • Alternative when spirometry unavailable
   • Measured over 2 weeks of twice-daily measurements
   • Less reliable than spirometry and BDR

4. Challenge Testing:

   • Recommended when other tests fail to confirm diagnosis
   • Options include direct bronchial challenge with methacholine or indirect testing using exercise (treadmill/bicycle)

Diagnostic Algorithm

1. Assessment of symptoms:

   • Recurrent wheeze is the most important symptom
   • Cough and breathing difficulty alone are nonspecific
   • Important: Symptoms alone are insufficient for diagnosis (strong recommendation against diagnosing based on symptoms alone) 1

2. Objective testing:

   • At least two abnormal objective test results are required
   • Sequence: FeNO → Spirometry → BDR testing (if spirometry abnormal)
   • If initial tests inconclusive: Consider challenge testing or PEFR variability

3. Trial of medication:

   • Not recommended as a diagnostic tool alone
   • Should only be considered in symptomatic children with abnormal spirometry and negative BDR
   • If trial initiated, objective tests must be repeated after 4-8 weeks 1, 2

Important Considerations and Pitfalls

Pitfalls in Diagnosis

1. Relying on symptoms alone:

   • Wheeze has sensitivity of 0.55-0.86 and specificity of 0.64-0.90 for asthma
   • Cough as the only symptom suggests alternative diagnoses
   • Children with chronic cough (>4 weeks) as the only symptom should be investigated according to ERS guidelines for chronic cough 1

2. Misinterpreting symptom improvement after medication:

   • Improvement after trial medication alone is insufficient for diagnosis
   • Objective testing before and after any trial is essential

3. Language and cultural barriers:

   • Terms to describe wheeze vary by language, culture, and age
   • Parents may describe stridor or rattles as wheeze
   • Some languages have no direct equivalent for "wheeze" 1

Age-Specific Considerations

• Children 5-16 years: Full diagnostic algorithm with objective testing is applicable
• Children <5 years: GINA recommendations differ (not covered in the evidence provided) as diagnostic tests are rarely performed in this age group 1, 3

Differences from Other Guidelines

GINA recommendations differ from other guidelines in several ways:

1. Compared to BTS/SIGN guidelines:

   • GINA provides a clearer diagnostic pathway
   • BTS/SIGN considers asthma a clinical diagnosis without recommending routine tests

2. Compared to UK NICE guidelines:

   • GINA recommends a lower FeNO cut-off (25 ppb vs 35 ppb)
   • GINA includes challenge testing as part of the diagnostic algorithm
   • GINA places less emphasis on PEFR variability testing

3. Reference standards:

   • GINA strongly recommends using lower limit of normal (LLN) derived from the Global Lung Function Initiative (GLI) as the reference standard for spirometry
   • Fixed cut-offs should only be used when LLN values are unavailable 1

In summary, GINA emphasizes that no single test can diagnose asthma in children, and recommends a systematic approach using multiple objective measurements rather than relying on symptoms or medication response alone.