Eosinophilic pneumonias in children: A review of the epidemiology, diagnosis, and treatment

Unusual pediatric lung infections: imaging findings

Pediatric lung infections continue to be a leading cause of pediatric morbidity and mortality. Although both pediatric and general radiologists are familiar with typical lung infections and their imaging findings in children, relatively rare lung infections continue to present a diagnostic challenge. In addition, the advances in radiological imaging and emergence of several new lung infections in recent years facilitated the need for up-to-date knowledge on this topic. In this review article, we discuss the imaging findings of pediatric lung infections caused by unusual/uncommon and new pathogens. We review the epidemiological, clinical, and radiological imaging findings of viral (coronavirus disease 2019, Middle East respiratory syndrome, bird flu), bacterial (Streptococcus anginosus, Francisella tularensis, Chlamydia psittaci), and parasitic lung infections (echinococcosis, paragonimiasis, amoebiasis). Additional disorders whose clinical course and imaging findings may mimic lung infections in children (hypersensitivity pneumonitis, pulmonary hemorrhage, eosinophilic pneumonia) are also presented, to aid in differential diagnosis. As the clinical presentation of children with new and unusual lung infections is often non-specific, imaging evaluation plays an important role in initial detection, follow-up for disease progression, and assessment of potential complications.

Monoclonal antibodies in idiopathic chronic eosinophilic pneumonia: a scoping review

BACKGROUND

Idiopathic chronic eosinophilic pneumonia (ICEP) is a rare disease characterized by pulmonary radiological alterations, peripheral eosinophilia, and demonstrated pulmonary eosinophilia. Oral steroids (OSs) are the standard management, but relapses occur in up to 50% of patients during the decrease or suspension of steroids, usually requiring reinitiation of treatment, exposing patients to secondary events derived from the management. Management with monoclonal antibodies has been proposed in these cases to control the disease and limit the secondary effects. The objective is to describe the extent and type of evidence regarding the use of monoclonal antibodies for ICEP.

METHODS

A panoramic review of the literature was performed. Observational and experimental studies of pediatric and adult populations that managed recurrent ICEP with monoclonal antibodies were included. Data search, selection, and extraction were performed by two independent reviewers.

RESULTS

937 studies were found. After applying the inclusion and exclusion criteria, 37 titles remained for the final analysis: a retrospective, observational, real-life study, two case series publications, and 34 case reports published in academic poster sessions and letters to the editor. In general, the use of monoclonal antibodies approved for severe asthma could be useful for the control of ICEP, since most of the results show a good response for clinical and radiological outcomes. Biological drugs seem to be a safer option for controlling relapses in ICEP, allowing lowering/suspension of OSs, and sometimes replacing them in patients intolerant to them, patients with significant comorbidities, and patients who have already developed adverse events.

CONCLUSION

The extent of the evidence supporting management of ICEP with monoclonal antibodies against IL-5 and IgE (omalizumab) is limited, but it could be promising in patients who present frequent relapses, in cortico-dependent individuals, or in patients in whom the use of steroids is contraindicated. The extent of the evidence for management with dupilumab is more limited. Studies with better design and structure are needed to evaluate quality of life and outcomes during a clear follow-up period. To our knowledge, this is the first scoping review of the literature showing the extent of the evidence for the management of ICEP with monoclonal antibodies.

Childhood Interstitial Lung Disease

Childhood interstitial lung disease (chILD) is a heterogeneous group of diseases with various clinical and imaging findings. The incidence and prevalence have increased in recent years, probably due to better comprehension of these rare diseases and increased awareness among physicians. chILDs present with nonspecific pulmonary symptoms, such as tachypnea, hypoxemia, cough, rales, and failure to thrive. Unnecessary invasive procedures can be avoided if specific mutations are detected through genetic examinations or if typical imaging patterns are recognized on computed tomography. Disease knowledge and targeted therapies are improving through international collaboration. Pulmonary involvement in systemic diseases is not uncommon. Pulmonary involvement may be the first finding in connective tissue diseases. This review aims to present a systematic patient-targeted approach to the diagnosis of chILD.

Sulfa-induced acute eosinophilic pneumonia

Acute eosinophilic pneumonia (AEP) is an infrequently seen interstitial lung disease secondary to medications. We report a series of 3 case of severe AEP which developed as a result of sulfa medication. 2 patients had received treatment with sulfamethoxazole for acne and 1 was treated with sulfasalazine for colitis. Patients were on sulfa medication for 1-3 weeks prior to presentation. All patients presented with fever, acute onset bilateral pulmonary infiltrates as well as marked peripheral eosinophilia. Mean eosinophil count was 2.21 × 10⁹/L. There was a lack of response to steroids. One patient required extracorporeal membrane oxygenation and prolonged mechanical ventilation via tracheostomy. 2 patients underwent successful lung transplantation (1 bilateral living-related lobar lung transplant and 1 orthotropic cardiopulmonary allotransplantation). In all cases lung biopsy and explants showed acute and organizing diffuse alveolar damage with increased interstitial and airspace eosinophils. To our knowledge, our series is the first to show the clinical features of sulfa induced AEP in an adolescent population.

Reverse butterfly pattern image with eosinophilia: Effective treatment with benralizumab-A case report

A 16-year-old adolescent presented with dry cough, fever, weight loss, night sweats, exercise intolerance, and eosinophilia. Computed tomography showed consolidations with "reverse butterfly" pattern. He responded well to corticosteroids but had frequent relapses. He became steroid dependent and developed steroid related morbidity. Benralizumab was prescribed with complete resolution of eosinophilia and lung infiltrates with no adverse effect.

Cutaneous manifestations of childhood Eosinophilic Granulomatosis with Polyangiitis (cEGPA): A case-based review

BACKGROUND/OBJECTIVES

This study seeks to better define the clinical presentation and histopathology of cutaneous manifestations in childhood eosinophilic granulomatosis with polyangiitis (cEGPA).

METHODS

Case reports were collected from Ovid Medline Database and PubMed using keyword identifiers from 1946 to 2017. Adult patients ≥ 18 years and cases not diagnosed with EGPA by the author were excluded. Sixty-five case reports of cEGPA were initially identified. These were reviewed individually, and fifty cases were determined to meet the American College of Rheumatology criteria for EGPA. No case series examining the cutaneous morphology and histopathology were identified. Cutaneous morphology, lesion location, and cutaneous histopathology results were recorded. Results were analyzed using summary statistics.

RESULTS

Sixty-four percent (32/50) of cEGPA patients presented with cutaneous manifestations. Twenty-nine cases provided specific morphological descriptions and lesion location. Common manifestations included purpura (15/29), subcutaneous nodules (8/29), and a macular/papular/maculopapular rash (8/29). However, twelve different cutaneous morphologies were identified in this review. Lesions occurred most commonly on the extremities (26/29). Twenty-two cases reported corresponding cutaneous histopathology, which revealed extravascular eosinophils (15/22), vasculitis (13/22), and granulomas (5/22). Only one biopsy sample (1/22) had all three classical EGPA characteristics of granulomas, extravascular eosinophils, and vasculitis.

CONCLUSION

With nearly two-thirds of cEGPA patients presenting with cutaneous manifestation, this study highlights the importance of clinical recognition of this disease by dermatologists. While the varied morphology of skin lesions and rarity of this disease makes cEGPA a difficult diagnosis, prompt recognition and treatment will improve outcomes in this patient population.

Interstitial Lung Diseases in Children, Adolescents, and Young Adults: Different from Infants and Older Adults

Childhood interstitial lung disease (chILD) in children, teenagers, and young adults presents a challenge to the clinicians and radiologist, given its rarity, diverse imaging manifestations, and often nonspecific clinical examination findings. This article discusses the utility of available imaging techniques and associated characteristic imaging findings, and reviews the 2015 chILD classification scheme, with clinical examples highlighting the imaging features to help the radiologist aid in an efficient and accurate multidisciplinary diagnosis of chILD.

Eosinophilic Pneumonia and Lymphadenopathy Associated With Vaping and Tetrahydrocannabinol Use

Idiopathic acute eosinophilic pneumonia is a rare and potentially life-threatening condition that is defined by bilateral pulmonary infiltrates and fever in the presence of pulmonary eosinophilia. It often presents acutely in previously healthy individuals and can be difficult to distinguish from infectious pneumonia. Although the exact etiology of idiopathic acute eosinophilic pneumonia remains unknown, an acute hypersensitivity reaction to an inhaled antigen is suggested, which is further supported by recent public health risks of vaping (electronic cigarette) use and the development of lung disease. In this case, a patient with a year-long history of vaping in conjunction with tetrahydrocannabinol cartridge use who was diagnosed with idiopathic acute eosinophilic pneumonia with associated bilateral hilar lymphadenopathy is described.

Practical Approach to Children Presenting with Eosinophila and Hypereosinophilia

Eosinophilia is not a rare finding in clinical practice, and often poses problems in terms of etiologic research and differential diagnosis. Peripheral eosinophilia is defined by a blood eosinophil count > 500 cells/μL. It is classified into mild (500-1500 cells/μl), moderate (1500-5000 cells/μl) and severe for an eosinophil count > 5000 cells /μl. The term "hypereosinophilia" defines a condition characterized by a blood eosinophil count >1500 cells/μl in at least two consecutive tests made with a minimum of a 4-week interval. The causes of eosinophilia are various, and can be summarized by the acronym "APLV" which refers to Allergic disorders, Parasitic infections, Leukemia/ Lymphomas (and solid tumors) and Vasculitis-Immunodeficiency diseases, with allergic disorders and parasitic infections representing the most commonly identified causes. Allergic disorders are usually associated with mild eosinophilia, whereas values >20.000 cell/μl are highly suggestive for myeloproliferative disorders. Eosinophils may also be directly responsible for organ damage, mainly at cardiac, pulmonary and cutaneous level, deriving from the release of the granule products, of lipidic mediators and cytokines. Therefore, in the physician's approach to a patient with persistent hypereosinophilia, it is also important to investigate the presence of organ involvement. In this review, we propose a diagnostic algorithm for children presenting with either blood eosinophilia or hypereosinophilia. This algorithm focuses on the patient's history and clinical manifestations as the first step and the level and persistence of blood eosinophilia as the second, and this can help the physician to identify patients presenting with an elevated blood eosinophil count that need further laboratory or instrumental investigations.

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.

Diagnostic pitfalls of acute eosinophilic pneumonia in an adolescent boy following cigarette smoking: A case report

RATIONALE

Acute eosinophilic pneumonia (AEP) is characterized by acute febrile respiratory symptoms, bilateral lung infiltrates, and pulmonary eosinophilia. AEP is closely related to cigarette smoking but is rarely suspected in pediatric cases despite the fact that there is a relatively high incidence of cigarette smoking among adolescents in Taiwan.

PATIENT CONCERNS

We report a case of a previously healthy 15-year-old boy who presented with fever and acute progressive dyspnea. Due to lack of awareness of cigarette smoking history in adolescents and the nonspecific signs and symptoms of AEP at early stages, the patient was initially treated as community-acquired pneumonia (CAP) but was unresponsive to antibiotics treatment.

DIAGNOSES

A combination of a recent onset smoking history and pulmonary eosinophilia on bronchoalveolar lavage confirmed the diagnosis of cigarette-induced AEP.

INTERVENTIONS

Corticosteroid treatment was prescribed.

OUTCOMES

The condition improved within 24 hours, with resolution of alveolar infiltrates on chest radiographs.

LESSONS

With the increasing incidence of smoking amongst adolescents in Taiwan, careful history questioning regarding cigarette smoking is necessary. Due to similarities in initial clinical and radiographic features of AEP and CAP, adolescents with suspected CAP who are unresponsive to antibiotic treatment but have a subsequent rise in peripheral eosinophils should raise the clinician's suspicion of AEP related to cigarette smoking.

Interleukin-35 in immune-related diseases: protection or destruction

Interleukin-35 (IL-35) is a recently identified heterodimeric cytokine in the IL-12 family. It consists of an IL-12 subunit α chain (P35) and IL-27 subunit Epstein-Barr virus-induced gene 3 (EBI3) β chain. Unlike the other IL-12 family members, it signals through four unconventional receptors: IL-12Rβ2-IL-27Rα, IL-12Rβ2-IL-12Rβ2, IL-12Rβ2-GP130, and GP130-GP130. Interleukin-35 signaling is mainly carried out through the signal transducer and activator of transcription family of proteins. It is secreted not only by regulatory T (Treg) cells, but also by CD8+ Treg cells, activated dendritic cells and regulatory B cells. It exhibits immunosuppressive functions distinct from those of other members of the IL-12 family; these are mediated primarily by the inhibition of T helper type 17 cell differentiation and promotion of Treg cell proliferation. Interleukin-35 plays a critical role in several immune-associated diseases, such as autoimmune diseases and viral and bacterial infections, as well as in tumors. In this review, we summarize the structure and function of IL-35, describe its role in immune-related disorders, and discuss the mechanisms by which it regulates the development and progression of diseases, including inflammatory bowel disease, collagen-induced arthritis, allergic airway disease, hepatitis, and tumors. The recent research on IL-35, combined with improved techniques of studying receptors and signal transduction pathways, allows for consideration of IL-35 as a novel immunotherapy target.

A Critical Evaluation of Safety Signal Analysis Using Algorithmic Standardised MedDRA Queries

INTRODUCTION

Algorithmic Standardised MedDRA^® Queries (aSMQs) are increasingly used to enhance the efficiency of safety signal detection. The manner that aSMQs affect capture of potential safety cases is unclear.

OBJECTIVES

Our objective was to characterise the performance of aSMQs with respect to their potential for double counting, the likelihood of events in aSMQ positive cases being clinically related, how frequently terms are used for algorithmically positive cases, and the face validity of positive cases based on the drug inducing events. We were also interested in what effect requiring symptoms to overlap temporally would have on performance.

METHODS

We reviewed adverse event (AE) datasets of New Drug Applications and Biological License Applications and compiled a database including preferred terms and corresponding SMQs, SMQ term categories, AE start day, AE duration, drug name, and Anatomical Therapeutic Chemical class. Two reviewers independently determined if the algorithm was met and, if so, whether the broad terms overlapped temporally.

RESULTS

A total of 107 marketing applications were reviewed, including 103,928 patients and 277,430 AEs. Use of algorithms condensed the number of AEs to between 5 and 8% and the incidence to about 1.5% relative to when the SMQs are used without the algorithm. Certain aSMQs exhibited a potential for overcounting. Requiring symptoms to temporally overlap helped to eliminate irrelevant cases.

CONCLUSIONS

Our findings demonstrate that algorithmic and temporal assessment increased specificity of case retrieval, though the reduction in the number of terms or incidence seemed excessive for certain aSMQs. Evaluating the day of AE onset and duration improve specificity through identification of outlying events. Identification of drug classes known to cause the aSMQ's clinical condition provides face validity for this tool, yet detection of cases associated with novel classes may provide new understanding of these disorders. Improvements in some of the SMQ term lists may improve the performance of SMQs in general.

TGFβ as a therapeutic target in cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease characterized by progressive lung disease. Most CF therapies focus on treating secondary pulmonary complications rather than addressing the underlying processes inducing airway remodeling and ineffective response to infection. Transforming growth factor beta (TGFβ) is a cytokine involved in fibrosis, inflammation, and injury response as well as a genetic modifier and biomarker of CF lung disease. Targeting the TGFβ pathway has been pursued in other diseases, but the mechanism of TGFβ effects in CF is less well understood. Areas covered: In this review, we discuss CF lung disease pathogenesis with a focus on potential links to TGFβ. TGFβ signaling in lung health and disease is reviewed. Recent studies investigating TGFβ's impact in CF airway epithelial cells are highlighted. Finally, an overview of potential therapies to target TGFβ signaling relevant to CF are addressed. Expert opinion: The broad impact of TGFβ signaling on numerous cellular processes in homeostasis and disease is both a strength and a challenge to developing TGFβ dependent therapeutics in CF. We discuss the challenges inherent in developing TGFβ-targeted therapy, identifying appropriate patient populations, and questions regarding the timing of treatment. Future directions for research into TGFβ focused therapeutics are discussed.

Drug-induced eosinophilic pneumonia: A review of 196 case reports

BACKGROUND AND OBJECTIVE

Eosinophilic pneumonia (EP) is an important subset of patients who present with pulmonary infiltrates and eosinophilia (PIE). EP is classified by chronicity and etiology and drug-induced EP is the main cause of secondary EP. The primary goal of this review was to examine all the case reports published since the syndrome was defined in 1990. It remains unclear whether acute or chronic EP (AEP or CEP) represent different diseases, and the secondary goal of this review is to determine if there are factors that may help distinguish these 2 entities.

METHODS

PubMed (MEDLINE and Medical Subject Headings) was searched for case reports of drug-induced EP or PIE syndrome published between 1990 and 2017. Case reports were only included if the diagnostic criteria for AEP or CEP were fulfilled. For each case, data were extracted pertaining to age, sex, type of medication associated with the disease, time from the onset of symptoms to diagnosis, eosinophil counts in the blood, eosinophil fractions in bronchoalveolar lavage (BAL) fluid, initial chest radiograph and computed tomography results, use of mechanical ventilation, and use of steroid treatment and recurrence.

RESULTS

We found 196 case reports describing drug-induced EP. The leading cause was daptomycin. From our review, we found that AEP is more common in younger patients with no gender preference. Eosinophilia in the blood at the time of diagnosis characterized only the CEP patients (80% in CEP vs. 20% in AEP). Abnormal findings on radiographic imagine was similar in both syndromes. A significant portion of AEP patients (20%) presented with acute respiratory failure requiring mechanical ventilation. Most patients with EP were treated with steroids with a higher rate of relapse observed in patients with CEP.

CONCLUSION

AEP is a much more fulminant and severe disease than the gradual onset and slowly progressive nature of CEP. The pathogenesis of AEP and CEP remains unclear. However, there is significant clinical overlap among AEP and CEP that are associated with drug toxicity, suggesting the possibility that AEP and CEP are distinct clinical presentations that share a common pathogenic pathway.

Eosinophil Development, Disease Involvement, and Therapeutic Suppression

Human eosinophils have characteristic morphologic features, including a bilobed nucleus and cytoplasmic granules filled with cytotoxic and immunoregulatory proteins that are packaged in a specific manner. Eosinophil production in the bone marrow is exquisitely regulated by timely expression of a repertoire of transcription factors that work together via collaborative and hierarchical interactions to direct eosinophil development. In addition, proper granule formation, which occurs in a spatially organized manner, is an intrinsic checkpoint that must be passed for proper eosinophil production to occur. In eosinophil-associated disorders, eosinophils and their progenitors can be recruited in large numbers into tissues where they can induce proinflammatory organ damage in response to local signals. Eosinophils are terminally differentiated and do not proliferate once they leave the bone marrow. The cytokine IL-5 specifically enhances eosinophil production and, along with other mediators, promotes eosinophil activation. Indeed, eosinophil depletion with anti-IL-5 or anti-IL-5Rα is now proven to be clinically beneficial for several eosinophilic disorders, most notably severe asthma, and several therapeutics targeting eosinophil viability and production are now in development. Significant progress has been made in our understanding of eosinophil development and the consequences of tissue eosinophilia. Future research efforts focused on basic eosinophil immunobiology and translational efforts to assist in the diagnosis, treatment selection, and resolution of eosinophil-associated disorders will likely be informative and clinically helpful.

IL-35 Suppresses Lipopolysaccharide-Induced Airway Eosinophilia in EBI3-Deficient Mice

EBI3 functions as the subunit of immune-regulatory cytokines, such as IL-27 and IL-35, by pairing with p28 and p35, respectively. We treated wild-type and EBI3-deficient mice with intratracheal administration of LPS and obtained bronchoalveolar lavage fluid (BALF) 24 h later. Although neutrophils were the predominant cells in BALF from both groups of mice, eosinophils were highly enriched and there was increased production of eosinophil-attracting chemokines CCL11 and CCL24 in BALF of EBI3-deficient mice. The bronchial epithelial cells and alveolar macrophages were the major producers of CCL11 and CCL24. Because no such increases in eosinophils were seen in BALF of p28/IL-27-deficient mice or WSX-1/IL-27Rα subunit-deficient mice upon intratracheal stimulation with LPS, we considered that the lack of IL-35 was responsible for the enhanced airway eosinophilia in EBI3-deficient mice. In vitro, IL-35 potently suppressed production of CCL11 and CCL24 by human lung epithelial cell lines treated with TNF-α and IL-1β. IL-35 also suppressed phosphorylation of STAT1 and STAT3 and induced suppressor of cytokine signaling 3. In vivo, rIL-35 dramatically reduced LPS-induced airway eosinophilia in EBI3-deficient mice, with concomitant reduction of CCL11 and CCL24, whereas neutralization of IL-35 significantly increased airway eosinophils in LPS-treated wild-type mice. Collectively, our results suggest that IL-35 negatively regulates airway eosinophilia, at least in part by reducing the production of CCL11 and CCL24.