Childhood Interstitial Lung Disease: Imaging Guidelines and Recommendations

Magnetic resonance imaging of pulmonary hypertension

Pulmonary hypertension is a rare but serious disease in children with potentially poor prognosis in the long term. Direct measurement of increased pressure in the pulmonary circulation requires right-heart catheterisation. Echocardiography is the imaging modality commonly used for suggesting the presence of pulmonary hypertension and estimating its severity. Recognition of structural and haemodynamic signs of increased pulmonary arterial pressure and pressure overload of the right ventricle at magnetic resonance (MR) imaging may contribute to the diagnosis of pulmonary hypertension and management of these patients. In this article, the structural, functional, and haemodynamic cardiovascular MR findings of paediatric pulmonary hypertension are reviewed. Typical diagnostic MR scenarios in children with suspected pulmonary hypertension or in children with disease associated with pulmonary hypertension are presented and discussed.

Bi-allelic LAMP3 variants in childhood interstitial lung disease: a surfactant-related disease

BACKGROUND

LAMP3 encodes a lysosomal membrane protein associated with lamellar bodies and has recently been proposed as a candidate gene for childhood interstitial lung diseases (chILD). Here, we identified two LAMP3 variants in a proband with chILD and performed functional validation of these variants as well as the previously reported variants to demonstrate the role of LAMP3 in pathology.

METHODS

LAMP3 variants were identified by exome sequencing. Ex vivo studies included mRNA analysis from nasal brushing and lung tissue and immunohistochemistry from lung biopsy. In vitro functional analyses in the A549 cell line included immunofluorescence staining and expression analysis of LAMP3. Interactions between LAMP3 and the surfactant protein (SP)-B and SP-C were evaluated by co-immunoprecipitation.

FINDINGS

Two heterozygous LAMP3 variants (Y302Qfs∗2 and T268M) were identified in a 15 year old boy with chILD. LAMP3 mRNA revealed that the frameshift variant resulted in nonsense-mediated mRNA decay. Reduced LAMP3 expression was confirmed in the patient's lung tissue. Functional studies of the T268M and the previously reported G288R variant revealed reduced levels of the mutant proteins. In addition, impaired N-glycosylation and protein instability were demonstrated with the T268M variant. Finally, we provided evidence for an interaction between LAMP3 and SP-B and SP-C, revealing a direct link between LAMP3 and surfactant metabolism.

INTERPRETATION

LAMP3 bi-allelic variants leading to LAMP3 dysfunction emerges as a cause of chILD associated with a heterogeneous phenotype that remains to be further defined. The close links between LAMP3 and surfactant metabolism could explain the pathophysiology of this genetic disease.

FUNDING

No specific funding.

Pediatric Diffuse Lung Disease in Infants: Imaging Findings and Histopathologic Correlation

Childhood interstitial lung disease (chILD) encompasses a diverse group of genetic, infectious, and inflammatory conditions affecting infants and children. The recognition and understanding of these entities have highlighted the necessity for more accurate classification. This group of rare heterogeneous diseases comprises more than 200 different conditions and has a combined estimated prevalence of less than one patient per 100 000 children. Hence, a systematic diagnostic approach is crucial. This article describes a diagnostic approach for pediatric diffuse lung diseases in infancy, including an analysis of clinical presentations and imaging and histologic features to effectively distinguish among various chILD entities. Although they often have overlapping and nonspecific radiologic features, some chILD entities may exhibit typical imaging findings, resulting in a CT diagnosis or aiding in narrowing the differential diagnosis, thus guiding the clinician to the appropriate genetic tests, potentially limiting unnecessary biopsies. This approach aims to enhance the understanding and diagnosis of chILD in infants, thereby facilitating improved patient care.

Clinical characteristics and prognosis of interstitial lung disease in systemic juvenile idiopathic arthritis: a two-center retrospective observational cohort study

BACKGROUND

Interstitial lung disease (ILD) is a serious complication in systemic juvenile idiopathic arthritis (SJIA). This study aimed to identify the clinical characteristics and prognosis of SJIA-ILD.

METHODS

A two-center retrospective cohort study was conducted on patients newly diagnosed with SJIA in China from October 2010 to December 2021. Clinical characteristics, laboratory parameters, outcomes, and relapse rates were compared between ILD and non-ILD groups.

RESULTS

A total of 176 children with SJIA were included, including 35 in ILD group and 141 in non-ILD group. The median age at onset of SJIA was 5.8 years (range 4.4-9.5) in patients with SJIA-ILD. It exhibited higher incidences of cervical spine (28.6%) and hip involvement (40.0%) in ILD group (P = 0.031 and P = 0.029, respectively). The incidence of macrophage activation syndrome (MAS) in ILD group reached up to 40%, significantly elevated than that in non-ILD group (P = 0.047). Children with ILD demonstrated a stronger inflammatory response and were more prone to developing lymphopenia (P = 0.009), requiring more combination therapy (P = 0.006) to control disease activity. 54.3% of patients received biologic therapies, with only three patient receiving biologics (one with IL-6 blockade, two with TNF inhibitor) prior to ILD onset and none receiving IL-1 blockade. The median follow-up duration was 6.0 years (range 3.9-9.5). The proportions of patients with SJIA-ILD achieving clinical inactive disease without glucocorticoids within 6 to 12 months of the treatment were significantly lower than control group (45.7% vs. 70.2%, P = 0.006). In ILD group, only 54.3% of patients achieved complete remission, and 17.1% were in a non-remission state, among whom two deaths from respiratory failure. There was no significant difference in disease relapse rates between the two groups (P > 0.05).

CONCLUSIONS

Patients with SJIA-ILD exhibited heightened inflammation, increased hip joint and cervical spine involvement, and were more susceptible to developing lymphopenia and MAS, suggesting a relatively poor prognosis. They required a prolonged time to control inflammation and more aggressive treatment strategies to achieve inactive status. The unsatisfactory rate of complete remission highlighted an urgent need for focused clinical strategies.

Childhood interstitial lung diseases: current understanding of the classification and imaging findings

Childhood interstitial lung diseases (chILDs) encompass a diverse group of disorders with a high mortality rate and severe respiratory morbidities. Recent investigations have revealed that the classification of adult ILDs is not valid for chILDs, particularly for ILDs of early onset. Therefore, Children's Interstitial Lung Disease Research Cooperative of North America proposed a new classification of chILDs for affected children under 2 years of age, and later another classification for affected individuals between 2 and 18 years of age. In this review, we provide an overview of the imaging findings of chILDs by classification. Most infantile ILDs have unique clinical, radiological, and molecular findings, while the manifestation of pediatric ILDs overlaps with that of adult ILDs.

Approach to the patient with Childhood Interstitial and Diffuse Lung Disease

Childhood Interstitial and Diffuse Lung Disease (chILD) encompasses a group of rare, chronic lung disorders in infants and children with overlapping clinical features but diverse etiologies. The clinical presentation of chILD is of chronic or recurring respiratory signs and symptoms, often including increased work of breathing and hypoxia, with diffuse radiographic abnormalities on chest imaging. Recognition can be challenging since some clinical features overlap with those of more common pediatric respiratory diseases including asthma and recurrent viral infections, among others. chILD should be considered as an underlying diagnosis when a patient's respiratory symptoms seem disproportionate to the clinical scenario and/or persist. The diagnostic process involves multiple steps and is tailored to the individual patient. Nearly all children will undergo imaging and pulmonary function testing, many will undergo bronchoscopy with bronchoalveolar lavage, many will receive genetic testing, and some will require lung biopsy. Treatment includes preventive care, evaluation for comorbidities, pharmacotherapy according to diagnosis, and ongoing disease surveillance, including revisiting genetic and histopathologic results as new clinical information becomes available and as our understanding of these rare disorders improves. The purpose of this review is to provide a broad approach to the diagnosis and management of patients with chILD.

Advancements in imaging in ChILD

Interstitial and diffuse lung diseases in children constitute a range of congenital and acquired disorders. These disorders present with signs and symptoms of respiratory disease accompanied by diffuse radiographic changes. In many cases, radiographic findings are nonspecific, while in other disorders, chest computed tomography (CT) is diagnostic in the appropriate context. Regardless, chest imaging remains central in the evaluation of the patient with suspected childhood interstitial lung disease (chILD). Several newly described chILD entities, spanning both genetic and acquired etiologies, have imaging that aid in their diagnoses. Advances in CT scanning technology and CT analysis techniques continue to improve scan quality as well as expand use of chest CT as a research tool. Finally, ongoing research is expanding use of imaging modalities without ionizing radiation. Magnetic resonance imaging is being applied to investigate pulmonary structure and function, and ultrasound of the lung and pleura is a novel technique with an emerging role in chILD disorders. This review describes the current state of imaging in chILD including recently described diagnoses, advances in conventional imaging techniques and applications, and evolving new imaging modalities that expand the clinical and research roles for imaging in these disorders.

Innovations in Childhood Interstitial and Diffuse Lung Disease

Children's interstitial and diffuse lung diseases (chILDs) are a heterogenous and diverse group of lung disorders presenting during childhood. Infants and children with chILD disorders present with respiratory signs and symptoms as well as diffuse lung imaging abnormalities. ChILD disorders are associated with significant health care resource utilization and high morbidity and mortality. The care of patients with chILD has been improved through multidisciplinary care, multicenter collaboration, and the establishment of patient research networks in the United Stated and abroad. This review details past and current innovations in the diagnosis and clinical care of children with chILD.