Introduction Interstitial lung disease in infants represents a heterogeneous group of diffuse pneumopathies causing chronic respiratory symptoms, associated with high mortality and morbidity. It is rare in children and differs considerably in aetiology and pathogenesis compared to adults, being a real diagnosis and therapeutic challenge.

Case report A 8 months old girl, with no history of prematurity and normal neonatal adaptation, but with significant personal history of neurodevelopment delay and recurrent bronchiolitis, was admitted with high fever, persistent cough, severe expiratory dyspnea and generalised cyanosis. Physical examination revealed an underweight child, with moderate axial hypotonia, in severe respiratory distress, tachypnea, wheezing, retractions, oxygen desaturation, symmetric breath sounds, multiple crackles, persistent cough, tachycardia, with no cardiac murmurs, digital clubbing, difficulty in feeding. Laboratory tests showed respiratory acidosis, hypercapnia and the chest x-ray with large opacity in the right superior lobe, diffuse alveolar infiltrates. Oxygen, systemic antibiotic, anti-inflammatory, bronchodilator and diuretic agents were initiated, with rapidly worsening of general condition, requiring prolonged mechanical ventilation. Echocardiography revealed moderate pulmonary hypertension and large patent ductus arteriosus, for which surgical ligation was performed, with favourable evolution, including pulmonary hypertension remission. However, despite of clinical and laboratory improvement in patient condition, any attempt to extubation lead to severe hypercapnia. In order to stop mechanical ventilation, a tracheostomy was performed. Altough successful extubation, the oxygen dependence persisted. We excluded the most common oxygen dependent respiratory diseases, after surgical treatment of congenital heart disease: cystic fibrosis, pulmonary hypertension, recurrent aspiration, immunodeficiency and neuromuscular disorders. Thoracic CT revealed atelectasis of right superior lobe, diffuse ground glass attenuation, linear opacities and honeycombing, suggestive for interstitial pneumopathy. Lung biopsy and histological diagnosis are yet to be performed. The patient was discharged with oral corticotherapy and continuous oxygen therapy.

Conclusion We presented a case of an infant with chronic respiratory failure, apparently secondary to congenital heart disease and recurrent bronchiolitis.