Congenital and Developmental Chest Anomalies

Congenital and Developmental Chest Anomalies

Congenital and Developmental Chest Anomalies

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Embryology & Overview - Lung Bud Bloopers

  • Lung Origin: Ventral foregut diverticulum (4th week).
  • Developmental Stages (📌 Every Pulmonologist Can See Alveoli):
    • Embryonic (Wk 3-7): Lung bud, trachea, bronchi; Tracheoesophageal Fistula (TEF) risk.
    • Pseudoglandular (Wk 5-17): Bronchial tree to terminal bronchioles; Gland-like. Congenital Pulmonary Airway Malformation (CPAM) forms.
    • Canalicular (Wk 16-26): Respiratory bronchioles, alveolar ducts; Surfactant production.
    • Saccular (Wk 24-Term): Terminal sacs (primitive alveoli) develop.
    • Alveolar (Late fetal - 8 yrs): Mature alveoli proliferate.
  • Anomaly Types (due to developmental errors):
    • Parenchymal (CPAM, sequestration)
    • Airway (Tracheal/bronchial atresia)
    • Vascular (Partial Anomalous Pulmonary Venous Return - PAPVR)

⭐ Congenital Pulmonary Airway Malformation (CPAM), formerly Cystic Adenomatoid Malformation (CCAM), is the most common congenital lung lesion, often detected antenatally. oka

Tracheobronchial Tree Troubles - Windpipe Woes

  • Tracheoesophageal Fistula (TEF)
    • Abnormal trachea-esophagus connection.
    • Most common: Type C (Gross classification) - Esophageal atresia + distal TEF (~85%).
    • 📌 VACTERL association: Vertebral, Anal, Cardiac, TEF, Renal, Limb defects.
  • Bronchial Atresia
    • Congenital focal obliteration of a segmental/lobar bronchus.
    • Leads to mucocele ("finger-in-glove" sign) & distal hyperinflation via collateral air drift.
    • Congenital and Developmental Chest Anomalies
  • Tracheomalacia / Bronchomalacia
    • Excessive dynamic expiratory collapse of trachea/bronchi (>50% reduction in AP diameter).
    • Diagnosis: Dynamic expiratory CT or bronchoscopy.
  • Bronchogenic Cysts
    • Congenital foregut duplication cyst; typically mediastinal (subcarinal, paratracheal commonest).
    • Imaging: CT shows well-defined, spherical, fluid density; MRI reveals high T2 signal.
    • ⭐ > Bronchogenic cysts are the most common primary mediastinal cysts.

Lung Parenchyma Puzzles - Spongy Surprises

  • Pulmonary Agenesis/Aplasia/Hypoplasia:
    • Agenesis: Total absence (lung, bronchus, vessels).
    • Aplasia: Rudimentary bronchus, no parenchyma.
    • Hypoplasia: ↓ lung volume, bronchi, alveoli.
    • CXR: Opacified hemithorax, ipsilateral mediastinal shift.
  • Congenital Lobar Emphysema (CLE):
    • Cause: Ball-valve obstruction → air trapping, progressive hyperinflation.
    • Imaging: Hyperlucent lobe, contralateral mediastinal shift, compressed adjacent lung.
    • 📌 Most common: LUL, RML. CXR Congenital Lobar Emphysema w Mediastinal Shift
  • Congenital Pulmonary Airway Malformation (CPAM): (fka CCAM)
    • Types 0-4 (Stocker). Type 1: Most common (~70%), large cysts (>2 cm).
    • Imaging: Cystic/solid lung mass; air-fluid levels.
    • Risk: Malignancy (pleuropulmonary blastoma).
  • Bronchopulmonary Sequestration (BPS):
    • Non-functional lung; no normal bronchial connection. Systemic arterial supply.
    • Intralobar (ILS): ~85%. No own pleura. Drains to pulmonary veins.
    • Extralobar (ELS): ~15%. Own pleura. Drains to systemic veins. Associated anomalies.

    ⭐ BPS hallmark: Aberrant systemic arterial supply (aorta/branches), best seen on CT Angiography.

Vascular & Diaphragmatic Defects - Plumbing & Partition Problems

  • Scimitar Syndrome (Hypogenetic Lung Syndrome)
    • Complex: right lung hypoplasia, dextrocardia, systemic arterial supply to lung.
    • Partial Anomalous Pulmonary Venous Return (PAPVR): anomalous vein (curved "scimitar" shape) drains to IVC.
    • CXR/CT: characteristic "Scimitar sign". Scimitar Syndrome CT and 3D Reconstruction
  • Pulmonary Arteriovenous Malformations (PAVMs)
    • Abnormal direct pulmonary artery-to-vein communication, bypassing capillaries; creates R-L shunt.

    ⭐ Strong association (~70%) with Hereditary Hemorrhagic Telangiectasia (HHT/Osler-Weber-Rendu syndrome).

    • Clinical: dyspnea, hypoxemia, hemoptysis. Risks: paradoxical emboli (stroke, brain abscess).
  • Congenital Diaphragmatic Hernia (CDH)
    • Diaphragmatic defect allowing abdominal viscera herniation into thorax.
    • Bochdalek Hernia: posterolateral (📌 Back & Left; ~90% cases, usually left-sided).
    • Morgagni Hernia: anteromedial, retrosternal, parasternal (rarer, often right-sided).
    • Major morbidity: pulmonary hypoplasia and persistent pulmonary hypertension.

High‑Yield Points - ⚡ Biggest Takeaways

  • Bochdalek hernia: Most common CDH, left posterolateral, bowel in chest.
  • CPAM (CCAM): Multicystic lung masses; Type 1 (large cysts) most common.
  • Pulmonary sequestration: Non-functional lung with systemic arterial supply (aorta).
  • Bronchogenic cysts: Mediastinal fluid-filled cysts from abnormal foregut budding.
  • CLE: Lobar hyperinflation causing mediastinal shift; often upper/middle lobes.
  • Scimitar syndrome: Anomalous right pulmonary venous return to IVC, hypoplastic right lung.
  • Azygos lobe: Azygos vein within an accessory fissure in the right upper lobe.

Practice Questions: Congenital and Developmental Chest Anomalies

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The most likely diagnosis in a newborn who had a radiopaque shadow with an air-fluid level in the chest along with hemivertebrae of the 6th thoracic vertebra on plain X-ray is –

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Flashcards: Congenital and Developmental Chest Anomalies

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In Macleod syndrome, CT scan will show the affected lung with _____ size and decreased vascularity, hyperexpansion, and hyperlucency (false emphysema)

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In Macleod syndrome, CT scan will show the affected lung with _____ size and decreased vascularity, hyperexpansion, and hyperlucency (false emphysema)

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