Pediatric Pulmonology and Respiratory Immunology
Domain 10 - Pediatric Pulmonology and Respiratory Immunology
This domain tests age-specific respiratory disease: bronchiolitis, childhood asthma, cystic fibrosis, primary ciliary dyskinesia, immunodeficiency and foreign-body aspiration. The Board favours questions on supportive care, when not to give antibiotics, and red flags for underlying immunodeficiency.
Core rules
- Bronchiolitis is usually caused by respiratory syncytial virus in infants under 2 years. Management is supportive: oxygen if saturations fall below 90–92%, hydration and nasal suction. Routine bronchodilators, corticosteroids, antibiotics and chest physiotherapy are not recommended.
- Childhood asthma: diagnosis needs recurrent symptoms and documented variable airflow limitation or bronchodilator response. GINA stepwise therapy starts with low-dose ICS; SABA-only treatment is not recommended for long-term control. Spacers are preferred for young children.
- Cystic fibrosis: sweat chloride >60 mmol/L confirms; 30–59 is intermediate and needs genetic or functional testing. Management includes airway clearance, inhaled mucolytics, pancreatic enzymes and CFTR modulators when mutation-eligible.
- Primary ciliary dyskinesia: neonatal respiratory distress, chronic wet cough, situs inversus, low nasal nitric oxide. Confirm with ciliary beat pattern and genetics.
- Immunodeficiency red flags: recurrent severe infections, unusual organisms, failure to thrive, family history and infection with live vaccines. Do not give live vaccines in severe combined immunodeficiency.
Worked example
A 6-month-old boy has coryza, tachypnoea, wheeze, crackles and SpO₂ 92%. He is feeding poorly. This is bronchiolitis. Admit for hydration and oxygen if saturations remain below 90–92%. Do not prescribe routine albuterol, systemic steroids or antibiotics. If he develops apnoea, exhaustion or rising CO₂, escalate to respiratory support. Antibiotics are reserved for secondary bacterial infection, which is uncommon.
Traps that cost marks
- Prescribing antibiotics for uncomplicated bronchiolitis.
- Using a SABA alone as maintenance therapy in childhood asthma.
- Diagnosing asthma in a preschool child from wheeze alone without documenting variability.
- Missing cystic fibrosis because the sweat chloride is in the intermediate range.
- Giving live vaccines to a child with severe immunodeficiency.
Key points
- Bronchiolitis is supportive; no routine bronchodilators, steroids or antibiotics.
- Childhood asthma maintenance includes ICS; SABA-only is outdated.
- Sweat chloride >60 mmol/L confirms cystic fibrosis.
- PCD: situs inversus, wet cough, low nasal nitric oxide.
- Live vaccines are contraindicated in severe immunodeficiency.
Respiratory Research, Evidence-Based Practice and Ethics
Domain 11 - Respiratory Research, Evidence-Based Practice and Ethics
This domain tests appraisal of respiratory literature and ethical practice. Expect questions on study design, diagnostic test statistics, confidence intervals, bias, guideline grading, consent, confidentiality and end-of-life decisions.
Core rules
- Study designs: randomised controlled trial for causal inference; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence; meta-analysis for pooled estimates. Intention-to-treat preserves randomisation but may dilute effect size.
- Sensitivity is the proportion of diseased patients who test positive; specificity is the proportion of non-diseased who test negative. Positive predictive value depends on prevalence and cannot be inferred from sensitivity and specificity alone.
- A 95% confidence interval describes the range compatible with the data; a p-value is the probability of data at least as extreme if the null hypothesis is true. It is not the probability that the null is true.
- Bias: selection, recall, publication, spectrum and confounding. Critical appraisal asks whether groups were comparable, outcome assessment was blinded, and follow-up was complete.
- Ethics: informed consent requires capacity, disclosure, understanding and voluntariness. Confidentiality can be breached only with justification or legal requirement. Resource allocation at end of life should follow transparent, non-discriminatory criteria.
Worked example
A new TB test has sensitivity 90% and specificity 95%. In a clinic where prevalence is 10%, PPV = (0.90 × 0.10) / [(0.90 × 0.10) + (0.05 × 0.90)] = 0.09 / 0.135 = 0.67. NPV = (0.95 × 0.90) / [(0.95 × 0.90) + (0.10 × 0.10)] = 0.855 / 0.865 = 0.99. So a positive result is wrong in about one-third of patients despite high sensitivity and specificity, because prevalence is low. Confirm positive results with culture or Xpert before starting toxic treatment.
Traps that cost marks
- Confusing sensitivity with PPV; PPV changes with prevalence.
- Interpreting a p-value as the probability that the null hypothesis is true.
- Ignoring intention-to-treat analysis in a trial with dropouts.
- Obtaining consent from a patient who lacks capacity without seeking a legal proxy.
- Breaching confidentiality in social media posts or case reports without anonymisation.
Key points
- RCTs test causal effects; cohorts measure incidence and prognosis.
- Sensitivity and specificity are prevalence-independent; PPV and NPV are not.
- A p-value is not the probability that the null hypothesis is true.
- Intention-to-treat analysis preserves randomisation.
- Informed consent requires capacity, disclosure and voluntariness.