Pulmonary and Respiratory Disorders
Asthma stepwise care
Reliever therapy is a short-acting beta-agonist by metered-dose inhaler with a valved holding chamber, preferred at every age. Persistent asthma adds inhaled corticosteroid; leukotriene modifiers and long-acting beta-agonists are add-ons - LABA monotherapy is contraindicated. For children 4 years and older, single maintenance and reliever therapy with an inhaled corticosteroid–formoterol combination is an option. Exacerbations: oral corticosteroids 1–2 mg/kg/day (max 60 mg) for 3–5 days; dexamethasone 0.6 mg/kg (max 16 mg) as a one- or two-dose alternative. Step down only after 3 months of good control, and always reassess inhaler technique and adherence first.
Cystic fibrosis pharmacotherapy
Pancreatic enzymes dosed by lipase units per gram of fat or per meal, generally 500–2500 units/kg/meal with a daily ceiling near 10,000 units/kg; give with every meal and snack. Fat-soluble vitamins A, D, E, K. Dornase alfa and 7% hypertonic saline improve clearance; azithromycin is immunomodulatory; inhaled tobramycin 300 mg twice daily on a 28-days-on/28-days-off cycle. CFTR modulators (elexacaftor/tezacaftor/ivacaftor) are genotype-specific.
Croup, bronchiolitis, pertussis
Croup: single dexamethasone 0.15–0.6 mg/kg plus nebulized epinephrine 1:1000 at 0.5 mL/kg (max 5 mL) for moderate-to-severe disease. Bronchiolitis is supportive - no routine bronchodilators, steroids, or antibiotics. Pertussis: azithromycin 10 mg/kg on day 1 then 5 mg/kg daily for 4 days.
Worked example
A 10 kg child with moderate croup: dexamethasone 0.6 mg/kg = 6 mg orally once, plus nebulized racemic or 1:1000 epinephrine 0.5 mL/kg = 5 mL. Observe at least 2–4 hours after epinephrine because symptoms can rebound.