Interstitial lung disease (ILD) is defined as a rare, heterogeneous group of parenchymal lung conditions that develop primarily because of underlying developmental or genetic disorders. Affected infants typically present with clinical syndromes characterized by dyspnea, tachypnea, crackles and hypoxemia. Until recently, the understanding of ILD in infants has been limited largely owing to a lack of evidence-based information of underlying pathogenesis, natural history, imaging findings and histopathological features. However, ILD in infants is now better understood and managed because of (1) advances in imaging methods that result in rapid and accurate detection, (2) improved thoracoscopic techniques for lung biopsy, (3) a consensus regarding the pathological criteria for these particular lung conditions and (4) a new classification system based on the underlying etiology of ILD. This article reviews the new classification system, imaging technique, clinical presentation and imaging findings of ILD in infants. Specialized knowledge of this new classification system in conjunction with recognition of characteristic imaging findings of ILD in infants has great potential for early and accurate diagnosis, which in turn can lead to optimal patient management.

Interstitial lung disease in infants: new classification system, imaging technique, clinical presentation and imaging findings

We report the case of a newborn with alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV), a rare condition of unknown etiology presenting in the neonatal period with significant persistent pulmonary hypertension. The diagnosis was made by lung biopsy and confirmed at autopsy. Specific genetic analysis demonstrated defects in the FOXF1 gene. The diagnosis of ACD/MPV requires a high level of suspicion and is made by lung biopsy or necropsy examination by a pediatric pathologist with experience in this condition. The availability of genetic testing has led to increasing diagnosis of patients with this lethal disorder and can influence their management, specifically by indicating the need for lung biopsy in a critically ill newborn.

Alveolar capillary dysplasia with misalignment of pulmonary [corrected] veins: concordance between pathological and molecular diagnosis.

We describe the clinical course of an infant with respiratory failure who underwent lung biopsy prior to cannulation for undergoing extracorporeal membrane oxygenation (ECMO). Pathology revealed alveolar capillary dysplasia, and ECMO was discontinued. Rapid diagnosis allowed for closure and saved resources. We recommend considering early biopsy in infants with atypical pulmonary hypertension.

Pre-cannulation lung biopsy shortens ECMO course.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare neonatal pathology that combines refractory hypoxemia with severe pulmonary arterial hypertension, and leads to death every time. Histologic examination of lung tissue confirms the diagnosis and is characterized by a decreased number of pulmonary capillaries, immature lobular development, and abnormal proximity between pulmonary arteries and veins. This abnormal proximity is responsible for an arteriovenous shunt. We report five cases confirmed by postmortem histology, which occurred over 14 years in Lower Normandy (France). The cumulative incidence is therefore of 1.8 for 100,000 births. In these five cases, the first symptoms appeared during the first hour of life and death occurred before 24h in four of five cases. The patient with the longest survival had mild histological lesions and delayed emergence of the first symptoms. Genitourinary and gastrointestinal anomalies were associated with ACD/MPV in two cases, and bilateral pulmonary hypoplasia in three cases. Optimized invasive ventilation, pulmonary vasodilators, vasoactive drugs, and pulmonary surfactant did not improve survival. Extracorporeal membrane oxygenation (ECMO) was not used. We present a review of the literature on ACD/MPV, a clinical and histological entity little known to both clinicians and pathologists, whereas a premortem diagnosis is possible and genetic counseling in affected families can be suggested.

Dysplasie alvéolo-capillaire avec mésalignement des veines pulmonaires : une cause de cyanose néonatale réfractaire létale

Pulmonary hypertension (PHT) is a condition defined by a mean pulmonary arterial pressure (PAP) of 25 mmHg or greater at rest and 30 mmHg or greater during exercise. PHT can be idiopathic or associated with a wide spectrum of etiological factors and conditions in the pediatric population, often resulting in diagnostic and therapeutic challenges. Due to recent advances in treatment which have markedly decreased the mortality and morbidity in pediatric patients with PHT, early and correct diagnosis is particularly essential in optimally managing children with PHT. In this chapter, we address the clinical presentation and the methods of evaluation of PHT in the pediatric population. Unique underlying pathophysiological processes and characteristic diagnostic study findings in idiopathic pulmonary arterial hypertension (IPAH) and common conditions typically associated with PHT in infants and children are also highlighted.

Pulmonary Hypertension in Infants and Children

Alveolar capillary dysplasia, although rare, is a universally fatal form of persistent pulmonary hypertension of the newborn. We report a case of a newborn male baby who developed respiratory distress and pneumothorax 11 h after an uncomplicated delivery. He deteriorated despite full ventilatory support and extracorporeal membrane oxygenation (ECMO). Open lung biopsy provided a diagnosis of alveolar capillary dysplasia and decision was made to withdraw treatment.

Anitha Vayalakkad

Papers

Alveolar capillary dysplasia presenting as pneumothorax: a case report and review of literature.