Chapter 20 · Congenital & Rare Lung Diseases

General principles · Nasopharyngeal abnormalities · Congenital stridor · Tracheoesophageal fistula · Lower airway abnormalities (tracheomalacia, bronchomalacia, lobar emphysema, CCAM, sequestration, agenesis) · Cardiac, diaphragm, chest wall, abdominal & multisystem diseases · Rare lung diseases (interstitial pneumonitides, surfactant disorders, pulmonary hemorrhage, pulmonary hypertension, thoracic tumors) · Spontaneous air leaks
📌 Core principles: Congenital stridor (laryngomalacia most common) usually self-resolves. Tracheoesophageal fistula presents with choking, cyanosis with feeds. Lower airway anomalies (CCAM, sequestration) may cause respiratory distress or be incidental. Interstitial lung disease in children (chILD) – surfactant protein mutations (SFTPC, ABCA3), neuroendocrine cell hyperplasia of infancy (NEHI). Pulmonary hypertension: idiopathic, heritable, or secondary (congenital heart disease, lung disease). Thoracic tumors: neuroblastoma, pleuropulmonary blastoma, teratoma.

📖 Congenital & Rare Lung Diseases – Key Concepts

👶 General principles & upper airway
Antenatal US may detect airway/lung lesions. Stridor: inspiratory (supraglottic), biphasic (glottic/subglottic), expiratory (tracheal). Laryngomalacia (60-70% of stridor) – self-resolves. Choanal atresia (bilateral → respiratory distress in newborn). Laryngeal cleft, webs, vocal cord palsy.
🫁 Lower airway & parenchymal anomalies
Tracheoesophageal fistula (TEF) – CXR shows NG tube in upper pouch, abdominal gas. CCAM (congenital cystic adenomatoid malformation) – multicystic, may cause hydrops, resection if symptomatic. Pulmonary sequestration – systemic arterial supply (aorta). Congenital lobar emphysema – overinflation of a lobe (LUL). Pulmonary agenesis/hypoplasia. Bronchogenic cyst.
❤️ Cardiac & chest wall
Vascular ring (double aortic arch, pulmonary artery sling) – causes stridor, dysphagia. Diaphragmatic hernia (CDH) – Bochdalek (left posterolateral), immediate respiratory distress, requires surgery, ECMO. Chest wall: asphyxiating thoracic dystrophy (Jeune syndrome).
🧬 Rare lung diseases – chILD
Interstitial pneumonitides: NEHI (neuroendocrine cell hyperplasia) – tachypnoea, crackles, hypoxaemia; good prognosis. Surfactant protein disorders (SFTPB, SFTPC, ABCA3) – diffuse lung disease, respiratory failure in infancy. Pulmonary hemorrhage: diffuse alveolar hemorrhage (vasculitis, IPH, HHT). Pulmonary arterial hypertension (PAH) – idiopathic, heritable (BMPR2), drug-induced. Thoracic tumors: pleuropulmonary blastoma (type I – cystic), neuroblastoma (posterior mediastinum), teratoma.

🔎 Symptom-based approach: neonatal stridor, respiratory distress, congenital anomalies

1️⃣
Newborn with inspiratory stridor, worse supine/feeding, improves with prone position. – Laryngomalacia (most common). Flexible bronchoscopy confirms. Self-resolves by 12-18 months; severe cases need supraglottoplasty.
2️⃣
Neonate with choking, cyanosis during feeds, excessive saliva. Failed NG tube passage. – Esophageal atresia with distal tracheoesophageal fistula (type C). CXR shows coiled NG tube in upper pouch, abdominal gas. Surgical repair.
3️⃣
Infant with recurrent wheeze, respiratory distress, CXR shows hyperlucent left upper lobe. – Congenital lobar emphysema (CLE). CT confirms; lobectomy if severe.
4️⃣
Prenatal diagnosis of multicystic lung lesion, postnatal respiratory distress. CT shows large cystic mass in left lower lobe, systemic feeding vessel from aorta. – Extralobar pulmonary sequestration. Surgical resection.
5️⃣
Infant with severe tachypnoea, hypoxaemia, diffuse crackles, normal CXR initially, progresses to ground-glass opacities. Surfactant protein gene suspected. – Surfactant protein deficiency (ABCA3, SFTPC). Lung biopsy, genetic testing, consider transplant.
⚠️ Red flags in congenital lung disease: Respiratory distress at birth (CDH, CCAM, TEF), bilious vomiting (malrotation), persistent cyanosis (cardiac/lung), failure to pass NG tube (esophageal atresia).

📋 Management algorithms: TEF, CDH, CCAM, chILD

🫁
Congenital diaphragmatic hernia (CDH) – neonatal resuscitation and surgery
▪️ Immediately after birth: intubation (avoid mask ventilation), orogastric tube decompression, IV access, maintain preductal SpO2 >85%.
▪️ Avoid bag-mask ventilation to prevent gastric distension.
▪️ Inhaled nitric oxide (iNO) for pulmonary hypertension; consider ECMO if refractory.
▪️ Delayed surgical repair after stabilization (usually after 24-48h).
▪️ Prognosis depends on lung-head ratio (LHR) and liver herniation.
🔪
Tracheoesophageal fistula (TEF) – perioperative management
▪️ Replogle tube continuous suction of upper pouch.
▪️ Head-up position, IV fluids, antibiotics (ampicillin, gentamicin).
▪️ Surgical repair via right thoracotomy (primary anastomosis).
▪️ Post-op: monitor for anastomotic leak, recurrent fistula, tracheomalacia.
🩺
Childhood interstitial lung disease (chILD) – approach
▪️ HRCT chest (ground-glass, cysts, mosaic attenuation).
▪️ Genetic testing: SFTPB, SFTPC, ABCA3, NKX2-1, FOXF1.
▪️ Bronchoscopy with BAL (exclude infection, aspiration).
▪️ Lung biopsy if diagnosis uncertain (video-assisted thoracoscopic surgery – VATS).
▪️ Treatment: supportive (oxygen, nutrition), hydroxychloroquine, steroids, azithromycin; lung transplantation for progressive disease.
🏥
Pulmonary sequestration – management
▪️ Confirm with CT angiography (systemic feeding vessel).
▪️ Surgical resection (lobectomy or segmentectomy) even if asymptomatic, to prevent recurrent infection.
▪️ Preoperative embolization of feeding artery if large.

💡 Reflex prompts – Congenital & Rare Lung Diseases

👶 A newborn with inspiratory stridor, worse supine, normal cry. Most common diagnosis?
Laryngomalacia (flexible bronchoscopy confirms).
🫁 A neonate with excessive drooling, choking with feeds, failed NG tube placement (stops at 10 cm). Diagnosis?
Esophageal atresia with distal tracheoesophageal fistula (TEF).
📊 A term infant with respiratory distress, scaphoid abdomen, bowel sounds in left chest. Diagnosis?
Congenital diaphragmatic hernia (Bochdalek). Immediate intubation, orogastric tube, surgery after stabilization.
🩻 A child with cystic lung lesion on CXR, CT shows feeding vessel from aorta. Diagnosis?
Pulmonary sequestration. Resection recommended.
🧬 Gene mutation most commonly associated with heritable pulmonary arterial hypertension?
BMPR2 (bone morphogenetic protein receptor type 2).
🩸 A child with hemoptysis, diffuse alveolar opacities, iron deficiency. Suspect?
Idiopathic pulmonary hemosiderosis (recurrent alveolar hemorrhage).
🔬 A term infant with respiratory failure, ground-glass opacities, no response to surfactant. Lung biopsy shows poorly formed alveoli, deficient surfactant protein. Likely gene?
ABCA3 (surfactant transporter deficiency).
💊 First-line treatment for pediatric pulmonary arterial hypertension (PAH).
Targeted therapies: bosentan (endothelin antagonist), sildenafil (PDE5i), prostacyclin analogs.
🎗️ A child with cystic lung mass, develops pneumothorax. CT shows thick-walled cysts. Most likely tumor?
Pleuropulmonary blastoma (type II or III). Surgical resection and chemotherapy.
🩺 A 3-month-old with tachypnoea, hypoxaemia, crackles, HRCT shows ground-glass opacities with no fibrosis, good response to hydroxychloroquine. Likely chILD diagnosis?
Neuroendocrine cell hyperplasia of infancy (NEHI) – characteristic radiographic and clinical course.