Pulmonary interstitial glycogenosis – A systematic analysis of new cases

Pulmonary interstitial glycogenosis in two neonates: Early recognition and use of corticosteroids

Pulmonary interstitial glycogenosis (PIG) is known to be associated with a wide variety of congenital conditions, though the extent to which PIG contributes to clinical presentation and outcomes in infants remains controversial. We describe two cases of infants with congenital anomalies and respiratory distress at birth who were diagnosed with PIG with differing clinical courses and response to methylprednisolone therapy. These cases highlight the importance of improved recognition of PIG and uncertainties about which patients may benefit from treatment.

Lung biopsy in infants with severe bronchopulmonary dysplasia

INTRODUCTION

Lung biopsy is infrequently performed in the population of infants with severe bronchopulmonary dysplasia (BPD). Yet, its presentation may overlap with other infant diffuse lung diseases, including those within the spectrum of childhood interstitial lung diseases (chILD). Lung biopsy might differentiate between these entities or identify those with an extremely poor prognosis. Both might alter the clinical management of some infants diagnosed with BPD.

METHODS

In this tertiary referral center, we drew on a retrospective cohort of 308 preterm infants with severe BPD. Of these, nine underwent lung biopsy between 2012 and 2017. We aimed to assess the indication for lung biopsy, the prior clinical history, safety of the procedure, and describe the biopsy findings. Finally, we considered management decisions in relation to the biopsy results in these patients.

RESULTS

All nine infants undergoing biopsy survived the procedure. The mean gestational age and birth weight of the nine patients were 30 ± 3 (range 27-34) weeks and 1421 ± 571 (range 611-2140) grams. All infants received serial echocardiograms to assess pulmonary hypertension, genetic testing, and computed tomography angiography (CTA) before biopsy. In all nine patients moderate to severe alveolar simplification was present and eight had some degree of pulmonary interstitial glycogenosis (PIG) ranging from focal to diffuse. Following biopsy, two infants with PIG received high dose systemic steroids and two separate infants had care redirected.

CONCLUSION

In our cohort, lung biopsy was safe and well tolerated. Findings from lung biopsy may aid decision making in selected patients as a part of a step-wise diagnostic algorithm.

Diffuse alveolar hemorrhage in children with interstitial lung disease: Determine etiologies!

OBJECTIVE

Diffuse alveolar hemorrhage (DAH) in children is a rare condition resulting from different underlying diseases. This study aimed at describing characteristics and diagnostic measures in children with ILD (children's interstitial lung disease, chILD) and DAH to improve the diagnostic approach by increasing clinician's awareness of diagnostic shortcomings.

PATIENTS AND METHODS

A retrospective data analysis of patients with ILD and DAH treated in our own or collaborating centers between 01/07/1997 and 31/12/2020 was performed. Data on clinical courses and diagnostic measures were systematically retrieved as case-vignettes and investigated. To assess suitability of diagnostic software-algorithms, the Human Phenotype Ontology (HPO) was revised and expanded to optimize conditions of its associated tool the "Phenomizer."

RESULTS

For 97 (74%) of 131 patients, etiology of pulmonary hemorrhage was clarified. For 34 patients (26%), no underlying condition was found (termed as idiopathic pulmonary hemorrhage, IPH). Based on laboratory findings or clinical phenotype/comorbidities, 20 of these patients were assigned to descriptive clusters: IPH associated with autoimmune features (9), eosinophilia (5), renal disease (3) or multiorgan involvement (3). For 14 patients, no further differentiation was possible.

CONCLUSION

Complete and sometimes repeated diagnostics are essential for establishing the correct diagnosis in children with DAH. We suggest assignment of patients with IPH to descriptive clusters, which may also guide further research. Digital tools such as the Phenomizer/HPO are promising, but need to be extended to increase diagnostic accuracy.

Pulmonary storage

Interstitial lung diseases (ILDs) are not just a matter of scarring or inflammation in the lung tissue. The lungs can also serve as a repository for products that can be produced in excessive amounts in the human body as a result of disease. Geneticaly based dysfunctions of lysosomal enzymes, which leads to an unefficient degradation and transport of various macromolecules from lysosomes, are considered to be storage diseases sensu stricto. ILDs were described in patients with Gaucher disease, Niemann-Pick disease and Fabry disease. In a broader context, however, the accumulation of various substances in the lung tissue is also encountered in cases of pediatric pulmonary interstitial glycogenosis (PIG), alveolar lipoproteinosis or pulmonary amyloidosis. The cause of PIG is not clear. The disease was first described in 2002 and a lung tissue sample is required to establish this diagnosis. Even though PIG usually goes well in childhood and the patients difficulties spontaneously subside over time, the long-term prognosis of the patients is unknown. Alveolar lipoproteinoses can be acquired (e.g. after massive exposure to silica dust), autoimmune, but also genetically determined. Unlike lysosomal storage diseases, in the case of pulmonary alveolar lipoproteinosis, accumulation of abnormal macromolecules occurs only in the lungs of affected individuals. Similarly, amyloidosis is not a single disease, but a group of diseases with different etiopathogenesis, as a result of which amyloid - a group of different proteins with a distinctvive conformation, which can be deposited in various organs, including the lungs - is formed. The diagnosis of pulmonary alveolar lipoproteinosis is based on the typical appearance and biochemical composition of the fluid obtained by bronchoalveolar lavage, the diagnosis of amyloidosis is histological.

Rare interstitial lung disease in a preterm neonate with congenital lobar emphysema

Congenital lobar emphysema (CLE)/congenital alveolar overdistension/congenital lobar overinflation or infantile lobar emphysema is a rare developmental anomaly of the lower respiratory tract which is characterised by hyperinflation of one or more of the pulmonary lobes. Histopathology may be variable, which may show abnormality in the cartilage, granulation tissue, mucosal folds, etc. We report a rare underlying histopathology in a preterm neonate with CLE. This entity referred to as pulmonary interstitial glycogenosis (PIG) is a group of heterogeneous lung disease affecting the lung parenchyma and is characterised by the presence of glycogen laden cells in the lung interstitium. This impairs the gas exchange and typically manifest as tachypnoea, retractions, hypoxia and increased respiratory support. Our case report highlights the association of CLE and PIG and a review of literature. One should always have a detailed histopathology in children presenting with CLE to rule out PIG.

Interstitial Lung Disease in Children: “Specific Conditions of Undefined Etiology” Becoming Clearer

Background: Children’s interstitial lung disease (chILD) is a rare group of pediatric lung diseases affecting the lung interstitium diffusely. In this work, we focused our attention on a specific infant group of chILD, also known as “specific conditions of undefined aetiology”, including pulmonary interstitial glycogenosis (PIG) and neuroendocrine cell hyperplasia of infancy (NEHI). Methods: PubMed was searched to conduct this narrative review. We searched for articles in English using the following keywords: (1) neuroendocrine cell hyperplasia of infancy; (2) NEHI; (3) pulmonary interstitial glycogenosis; (4) PIG; (5) chILD. Results: An increasing interest and insight into these two conditions have been reported. The updated literature suggests that it is possible to look at these disorders as a continuum of diseases, rather than two different entities, since they share a pulmonary dysmaturity. Conclusions: NEHI and PIG are featured by dysmaturity of airway development and consequent respiratory distress. Understanding the underlying pathogenic mechanisms would lead to identifying new targeted therapies to ameliorate the mortality and morbidity of these rare conditions.

An Infant with Persistent Respiratory Failure Associated with Refractory Pulmonary Hypertension: Pulmonary Interstitial Glycogenosis

Pulmonary interstitial glycogenosis (PIG) is a disease of unknown etiology. It is part of the interstitial lung diseases, corresponding to the compartment of the fetal pulmonary interstitium. It typically presents within the first week of life as refractory respiratory distress with tachypnea and persistent hypoxemia, and it is not associated with glycogen deposition in other organs. Usually, there is a clinical improvement and good prognosis after steroid therapy unless there are associated conditions such as congenital heart disease, pulmonary hypertension, or genetic disorders. We report a case diagnosed by lung biopsy at 4 months of age in a male preterm born, small for gestational age infant, who developed refractory hypoxemia and pulmonary hypertension with fatal outcome. There was no response to steroids and hydroxychloroquine. He was not candidate for extracorporeal membrane oxygenation. PIG should be considered in the differential diagnosis of persistent respiratory distress and hypoxemia despite standard treatment, even after the first month of life.

Interstitial lung disease in infancy and early childhood: a clinicopathological primer

Children's interstitial lung disease (chILD) encompasses a wide and heterogeneous spectrum of diseases substantially different from that of adults. Established classification systems divide chILD into conditions more prevalent in infancy and other conditions occurring at any age. This categorisation is based on a multidisciplinary approach including clinical, radiological, genetic and histological findings. The diagnostic evaluation may include lung biopsies if other diagnostic approaches failed to identify a precise chILD entity, or if severe or refractory respiratory distress of unknown cause is present. As the majority of children will be evaluated and diagnosed outside of specialist centres, this review summarises relevant clinical, genetic and histological findings of chILD to provide assistance in clinical assessment and rational diagnostics.

ILD of childhood is comparable by name only to lung disease in adults. A dedicated interdisciplinary team is required to achieve the best possible outcome. This review summarises the current clinicopathological criteria and associated genetic alterations.https://bit.ly/3mpxI3b

Neonatal interstitial lung disease in a girl with Jacobsen syndrome: a case report

BACKGROUND

We report a case of the neonatal interstitial lung disease pulmonary interstitial glycogenosis in a girl with Jacobsen syndrome. While Jacobsen syndrome is caused by a deletion on the long arm of chromosome 11 and is genetically confirmed, pulmonary interstitial glycogenosis is of unknown etiology and is diagnosed by lung biopsy. Pulmonary interstitial glycogenosis has not previously been described in association with Jacobsen syndrome.

CASE PRESENTATION

A term newborn small for gestational age Caucasian girl presented with respiratory distress, pulmonary hypertension, congenital heart defects, immunodeficiency, and thrombocytopenia. She was diagnosed with Jacobsen syndrome, but also had pulmonary interstitial glycogenosis, which contributed to significant morbidity. There was striking clinical improvement after steroid treatment of the pulmonary interstitial glycogenosis.

CONCLUSIONS

Interstitial lung disease should be considered as a differential diagnosis when respiratory distress and hypoxemia in the perinatal period worsens or persists despite standard treatment. Importantly, pulmonary interstitial glycogenosis may be treatable with corticosteroids. Whether there is a genetic link between pulmonary interstitial glycogenosis and Jacobsen syndrome is still unknown.

Congenital interstitial lung diseases: What the anesthesiologist needs to know

Congenital interstitial lung diseases can affect both adults and children. Pediatric congenital interstitial lung diseases generally carry high risk for morbidly and mortality and include congenital alveolar capillary dysplasia with misalignment of pulmonary veins, congenital alveolar dysplasia, acinar dysplasia, congenital pulmonary lymphangiectasis, diffuse pulmonary lymphangiomatosis, neuroendocrine cell hyperplasia of infancy, pulmonary hemosiderosis, pulmonary alveolar proteinosis, and pulmonary interstitial glycogenosis. Given their usual non-specific clinical presentation, they are frequently misdiagnosed and recognized late, particularly in children who have been apparently healthy for several years (eg, diffuse pulmonary lymphangiomatosis). Some diseases have a very poor prognosis, whereas others have a benign course with appropriate treatment. The current manuscript reviews congenital interstitial lung diseases that typically affect neonates and young children and may be encountered by the pediatric anesthesiologist.

Pulmonary growth abnormalities as etiologies for pediatric pulmonary hypertension

Pulmonary growth abnormality (PGA) is a common type of diffuse lung disease in infants. Although the histologic and radiographic features of PGA have been described in the literature in varying detail, the clinical spectrum of disease has not. The array of case series and case reports has led to a clinical picture that could be confusing to clinicians. We describe three subsets of PGA, including its association with the histologic marker of pulmonary interstitial glycogenosis, and its common association with pulmonary hypertension. We propose a new approach to what we consider an increasingly broad array of different disease entities.

[Interstitial lung disease in infancy and early childhood]

Diffuse interstitial lung disease of infancy (chILD) shows a spectrum of disease substantially different from that of adults. Established classification systems divide chILD into conditions that are more prevalent in infancy and conditions that occur at any age. The classification is based on a multidisciplinary approach including clinical, radiological, genetic, and histological findings. Lung biopsies become necessary if other diagnostic investigations have not identified a precise chILD or if severe or refractory respiratory distress of unknown cause is present. As the majority of pediatric lung biopsies will be received first by pathologists outside of specialist centers this review summarizes relevant clinical and histological findings of chILD.

A homozygous variant in growth and differentiation factor 2 (GDF2) may cause lymphatic dysplasia with hydrothorax and nonimmune hydrops fetalis

The etiology of nonimmune hydrops fetalis is extensive and includes genetic disorders. We describe a term-born female neonate with late onset extensive nonimmune hydrops, that is, polyhydramnios, edema, and congenital bilateral chylothorax. This newborn was successfully treated with repetitive thoracocentesis, total parenteral feeding, octreotide intravenously and finally surgical pleurodesis and corticosteroids. A genetic cause seemed plausible as the maternal history revealed a fatal nonimmune hydrops fetalis. A homozygous truncating variant in GDF2 (c.451C>T, p.(Arg151*)) was detected with exome sequencing. Genetic analysis of tissue obtained from the deceased fetal sibling revealed the same homozygous variant. The parents and two healthy siblings were heterozygous for the GDF2 variant. Skin and lung biopsies in the index patient, as well as the revised lung biopsy of the deceased fetal sibling, showed lymphatic dysplasia and lymphangiectasia. To the best of our knowledge, this is the first report of an association between a homozygous variant in GDF2 with lymphatic dysplasia, hydrothorax and nonimmune hydrops fetalis.

Interstitial lung diseases in children

Interstitial lung disease (ILD) in children (chILD) is a heterogeneous group of rare respiratory disorders that are mostly chronic and associated with high morbidity and mortality. The pathogenesis of the various chILD is complex and the diseases share common features of inflammatory and fibrotic changes of the lung parenchyma that impair gas exchanges. The etiologies of chILD are numerous. In this review, we chose to classify them as ILD related to exposure/environment insults, ILD related to systemic and immunological diseases, ILD related to primary lung parenchyma dysfunctions and ILD specific to infancy. A growing part of the etiologic spectrum of chILD is being attributed to molecular defects. Currently, the main genetic mutations associated with chILD are identified in the surfactant genes SFTPA1, SFTPA2, SFTPB, SFTPC, ABCA3 and NKX2-1. Other genetic contributors include mutations in MARS, CSF2RA and CSF2RB in pulmonary alveolar proteinosis, and mutations in TMEM173 and COPA in specific auto-inflammatory forms of chILD. However, only few genotype-phenotype correlations could be identified so far. Herein, information is provided about the clinical presentation and the diagnosis approach of chILD. Despite improvements in patient management, the therapeutic strategies are still relying mostly on corticosteroids although specific therapies are emerging. Larger longitudinal cohorts of patients are being gathered through ongoing international collaborations to improve disease knowledge and targeted therapies. Thus, it is expected that children with ILD will be able to reach the adulthood transition in a better condition.

Pediatric Pulmonology Year in Review 2018: Rare lung disease, neuromuscular disease, and diagnostic testing

Pediatric Pulmonology publishes original research, case reports, and review articles on topics related to a wide range of children's respiratory disorders. In this article, we highlight the past year's publications in the topic areas of rare lung diseases, respiratory complications of neuromuscular disorders, and diagnostic testing, as well as selected literature in these areas from other journals.

Isolated pulmonary interstitial glycogenosis associated with alveolar growth abnormalities: A long-term follow-up study

INTRODUCTION

Pulmonary interstitial glycogenosis (PIG) is a rare infant interstitial lung disease characterized by an increase in the number of interstitial mesenchymal cells, presenting as enhanced cytoplasmic glycogen, and is considered to represent the expression of an underlying lung development disorder.

METHODS

This study describes the clinical, radiological, and functional characteristics and long-term outcomes (median 12 years) of nine infants diagnosed with isolated PIG associated with alveolar simplification in the absence of other diseases.

RESULTS

All patients presented with tachypnea. Additionally, seven patients had breathing difficulties and hypoxemia. Abnormalities in chest-computerized tomography (CT) with a pattern of ground-glass opacity, septal thickening, and air trapping were observed in all individuals, with images suggesting abnormal alveolar growth (parenchymal bands and architectural distortion). All lung biopsies showed alveolar simplification associated with an increased number of interstitial cells, which appeared as accumulated cytoplasmic glycogen. In the follow-up, all patients were asymptomatic. The respiratory function test was normal in only two patients. Five children showed an obstructive pattern, and two children showed a restrictive pattern. Chest-CT, performed after an average of 6.5 years since the initial investigation, revealed a partial improvement of the ground-glass opacity pattern; however, relevant alterations persisted.

CONCLUSION

Although the patients with PIG in the absence of other associated pathologies had a good clinical outcome, significant radiographic alterations and sequelae in lung function were still observed after a median follow-up of 12 years, suggesting that PIG is a marker of some other persistent abnormalities in lung growth, which have effects beyond the symptomatic period.

Diagnostic and clinical course of pulmonary interstitial glycogenosis: The tip of the iceberg

"Pulmonary Interstitial Glycogenosis: Diagnostic Evaluation and Clinical Course," written by Liptzin et al is a timely and insightful phenotypic summary of a rare pediatric interstitial lung disease. Twenty-four infants with biopsy-proven pulmonary interstitial glycogenosis (PIG) were reviewed at their center. Genetic analysis, bronchoscopy results, imaging, biopsy, and cardiology findings were described, and treatment decision and clinical outcomes were discussed.