US classification of children's’ interstitial lung disease (ILD)
| Category | Illustrative diseases |
|---|---|
| Diffuse developmental disorders (n=11) | Acinar dysplasia (n=1), congenital alveolar-capillary dysplasia (n=2) and alveolar-capillary dysplasia with misalignment of the pulmonary veins (n=8) |
| Growth abnormalities reflecting deficient alveolarisation (n=46) | Pulmonary hypoplasia (n=7); chronic neonatal lung disease (bronchopulmonary dysplasia) (n=20); related to chromosomal disorders (n=15); related to congenital heart disease (n=4) |
| Specific conditions of undefined aetiology (n=24) | Pulmonary interstitial glycogenosis (n=18); neuroendocrine cell hyperplasia of infancy (n=6) |
| Surfactant dysfunction disorders (n=18) | SpB gene mutations (n=0); SpC gene mutations (n=7); ABCA3 gene mutations (n=6). TTF-1 and GM-CSF α- and β- chain receptor mutations would now be added; histology consistent with Sp disorder but none detected (n=5 in total; pulmonary alveolar proteinosis (n=2), chronic pneumonitis of infancy (n=1), DIP (n=1), and NSIP (n=1)) |
| Disorders of the normal host, presumed immune intact (n=23) | Infectious and post-infectious (n=17); Environmental agents (n=2 in total; hypersensitivity pneumonitis (n=2)); aspiration syndromes (n=3); eosinophilic pneumonia (n=1) |
| Disorders resulting from systemic disease processes (n=6) | Collagen vascular disease (n=4); storage disease (n=1); sarcoidosis (n=0); Langerhans cell histiocytosis (n=0); malignant infiltrates (n=1) |
| Disorders of the immunocompromised host (n=28) | Opportunistic infections (n=20); iatrogenic (n=3); related to transplant and rejection (n=0); diffuse alveolar damage, unknown aetiology (n=5) |
| Disorders masquerading as ILD (n=9) | Arterial hypertensive vasculopathy (n=8); venous engorgement secondary to heart disease (n=1); veno-occlusive disease (n=0); lymphatic disorders (n=0) |
ABCA3, ATP-binding cassette subfamily A member 3; DIP, desquamative interstitial pneumonia; GM-CSF, granulocyte macrophage colony stimulating factor; NSIP, non-specific interstitial pneumonia; Sp, surfactant protein; TTF, thyroid transcription factor.