Interstitial lung disease in childhood and adulthood

Interstitial lung disease (ILD) in childhood and adulthood, also known as diffuse parenchymal lung disease, encompasses a broad and heterogeneous group of rare pulmonary disorders characterized by inflammation and/or fibrosis of the lung interstitium — the tissue and space surrounding the air sacs (alveoli) of the lungs. These conditions impair gas exchange, leading to progressive respiratory insufficiency. The Orphanet classification (ORPHA:264757) serves as a grouping category for various forms of ILD that can manifest across the age spectrum, from childhood through adult life, distinguishing them from forms that are exclusively neonatal or infantile in onset. Key symptoms commonly include chronic cough, progressive exertional dyspnea (shortness of breath with activity), tachypnea (rapid breathing), hypoxemia (low blood oxygen levels), failure to thrive in children, and exercise intolerance. Physical examination may reveal crackles on lung auscultation and, in advanced cases, digital clubbing and signs of pulmonary hypertension. High-resolution computed tomography (HRCT) of the chest typically shows characteristic patterns such as ground-glass opacities, reticular markings, honeycombing, or traction bronchiectasis. Lung biopsy may be required for definitive diagnosis in some cases. The causes of childhood and adult ILD are diverse and include genetic mutations (such as those in surfactant protein genes SFTPC, SFTPB, ABCA3, NKX2-1, and telomere-related genes), autoimmune and connective tissue diseases, hypersensitivity pneumonitis, sarcoidosis, and idiopathic forms such as idiopathic pulmonary fibrosis (IPF). Treatment depends on the underlying etiology and may include corticosteroids, immunosuppressive agents (such as azathioprine, mycophenolate mofetil, or hydroxychloroquine), antifibrotic therapies (nintedanib and pirfenidone, particularly for IPF), supplemental oxygen, and pulmonary rehabilitation. Lung transplantation may be considered in severe, progressive cases refractory to medical therapy. Given the heterogeneity of this disease group, management is best guided by multidisciplinary teams at specialized centers.

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