Approach to the patient with suspected hypereosinophilic syndrome

Clinical Management of Persistent Hypereosinophilia

Blood eosinophilia remains a common finding in the general population, whereas hypereosinophilia (HE) is extremely rare. Different non-hematologic and hematologic disorders may be accompanied by blood eosinophilia. Clinical manifestations of eosinophilia-related disorders range from mild to life-threatening. Given the various symptoms, a comprehensive approach and close multidisciplinary cooperation are strongly recommended. Hypereosinophilic syndromes (HES) encompass a complex group of disorders defined as persistent peripheral blood HE ≥ 1500/mm3 and end-organ damage. An initial step in a diagnostic algorithm of HE includes the evaluation of secondary, potentially easy-to-treat causes. This HES variant is called reactive and often remains beyond the interest of hematologists. The further evaluation for primary causes of HE relies on a combination of different specialized tests, which are mostly available in hematologic centers and include most of all morphologic assessments of peripheral blood and bone marrow, cytogenetics, and molecular studies. Using these sophisticated methods, one can diagnose the specific HES subtypes based on genetic findings and categorize them according to currently applicable classifications. The choice of therapy differs between HES variants, ranging from corticosteroids and anti-interleukin-5 monoclonal antibodies for not-molecularly defined variants to oral molecules directed against molecular targets. This review presents eosinophilia-related disorders from a hematologic perspective.

11-Year-Old Boy With B-ALL-Induced Hypereosinophilic Syndrome Presenting as Acute Encephalopathy

Encephalopathy is a disturbance in neurologic function. It is commonly attributed to infectious and inflammatory etiologies but encompasses a wide differential. Hypereosinophilic syndrome (HES) is a rare cause of encephalopathy that is associated with underlying infection or malignancy. We present a pediatric patient who experienced several days of worsening encephalopathy and neurological deterioration associated with influenza B infection and hypereosinophilia. A thorough workup ultimately revealed a diagnosis of HES secondary to B cell acute lymphoblastic leukemia (B-ALL). This case exemplifies the importance of maintaining a broad approach to the diagnostic evaluation, treatment, and management of encephalopathy.

Catastrophic Thrombosis: A Narrative Review

Catastrophic thrombosis is a severe condition characterized by a hypercoagulable tendency, leading to multiple thromboembolic events in different blood vessels, usually within a short timeframe. Several conditions have been associated with the development of catastrophic thrombosis, including the catastrophic antiphospholipid syndrome, thrombotic anti-platelet factor 4 immune disorders, thrombotic microangiopathies, cancers, the hyper-eosinophilic syndrome, pregnancy, infections, trauma, and drugs. Thrombotic storm represents a medical emergency whose management represents a serious challenge for physicians. Besides the prompt start of anticoagulation, a patient's prognosis depends on early recognition and possible treatment of the underlying condition. In this narrative review, we summarize the main characteristics of catastrophic thrombosis, analyzing the various conditions triggering such life-threatening complication. Finally, an algorithm with the diagnostic workup and the initial management of patients with catastrophic thrombosis is presented.

Refractory Idiopathic Hypereosinophilic Syndrome Presenting with Myocarditis and Responding to Imatinib: A Case Report

Idiopathic hypereosinophilic syndrome (HES) is a rare disorder characterized by persistent hypereosinophilia leading to multi-organ dysfunction. Its clinical manifestations vary widely; however, cardiac and neurological involvement are the leading causes of morbidity and mortality. Corticosteroids are the initial treatment of choice, but in idiopathic HES resistant to corticosteroids, second-line therapy should be considered. Imatinib is usually reserved for patients with a positive platelet-derived growth factor receptor A (PDGFR-A) mutation; however, its use in idiopathic HES with a negative PDGFR mutation is debatable given that such patients usually respond well to high doses of corticosteroids. Here, we present a case of a young male with corticosteroid-refractory idiopathic HES successfully treated with imatinib. The patient presented with features suggestive of acute coronary syndrome and confusion. A coronary angiogram was normal. Echocardiography showed an ejection fraction of 37%, and brain imaging showed evidence of multifocal cerebral thromboembolic infarcts. During the hospital stay, the patient developed diffuse alveolar hemorrhage. Biochemically, it was noted that the patient had hypereosinophilia. Through thorough workup, a diagnosis of idiopathic HES was established. The patient was started on high-dose corticosteroid (500 mg intravenous methylprednisolone daily) followed by a maintenance dose of prednisolone (0.5 mg/kg/day), but had no response. Second-line therapy with imatinib (400 mg per oral daily for 4 days and then down-titrated to 100 mg daily) was initiated, which resulted in drastic biochemical and clinical improvements. This case report supports the efficacy of imatinib as a second-line agent in corticosteroid-resistant idiopathic HES with a negative PDGFR mutation.

Cardiac Abnormalities in Hypereosinophilic Syndromes

Hypereosinophilia (HE) is defined as an eosinophil count exceeding 1500 cells/microL in peripheral blood in two tests, performed with an interval of at least one month and/or anatomopathological confirmation of HE, with eosinophils comprising more than 20% of all nucleated cells in the bone marrow. Hypereosinophilic syndrome (HES) indicates the presence of HE with organ involvement due to eosinophil action, which can be classified as primary (or neoplastic), secondary (or reactive), and idiopathic. Cardiac involvement occurs in up to 5% of cases in the acute phase and 20% of the chronic phase of the disease, ranging from oligosymptomatic cases to fulminant acute myocarditis or chronic restrictive cardiomyopathy (Loeffler endomyocarditis). However, the degree of cardiac dysfunction does not directly correlate with the degree of eosinophilia. The cardiac involvement of HES occurs in three phases: initial necrotic, thrombotic, and finally necrotic. It can manifest as heart failure, arrhythmias, and thromboembolic phenomena. The diagnosis of cardiopathy is based on multimodality imaging, with an emphasis on the importance of echocardiography (echo) as the primary examination. TTE with enhanced ultrasound agents can be used for better visualization, allowing greater accuracy in assessing ventricular apex, and myocardial deformation indices, such as longitudinal strain, may be reduced, especially in the ventricular apex (reverse apical sparing). Cardiac magnetic resonance imaging allows the characterization of subendocardial late gadolinium enhancement, and endomyocardial biopsy is considered the gold standard in diagnosing cardiopathy. Treatment is based on the etiology of HES.

Probable idiopathic hypereosinophilic syndrome: A case report of severe multi-organ eosinophilic involvement in a young male presenting with heart failure

Hypereosinophilic syndrome (HES) is a disorder characterized by elevated levels of eosinophils, which may be associated with multi-organ involvement depending on severity. The recent diagnostic criteria for idiopathic HES require an elevated absolute eosinophil count (AEC) above 1500 cells/mcL with evidence of tissue damage. We present a case of a 37-year-old male firefighter with a purported history of eosinophilic bronchitis who was referred to the hospital with syncopal episodes and a persistent productive cough. The patient showed an AEC of 4500 cells/mcL on admission associated with high inflammatory markers. Cardiac imaging demonstrated acute myocarditis with heart failure and a reduced ejection fraction. Chest imaging was initially suggestive of community-acquired pneumonia. Workup was negative for a malignant etiology; infectious causes similarly were excluded. After a multidisciplinary evaluation, a diagnosis of idiopathic HES was made and steroids were instituted with rapid resolution of symptoms. Our case illustrates the importance of considering hypereosinophilia as a precipitating factor for acute heart failure in an otherwise healthy adult. An expeditious diagnosis can lead to early initiation of steroids to avoid progression toward multi-organ failure.

Incessant Ventricular Tachycardia: An Atypical Presentation of Chronic Eosinophilic Leukemia

Hypereosinophilic syndrome comprises a diverse and intricate array of rare disorders, exhibiting clinical manifestations that extend across various medical subspecialties. Within its myeloid form, chronic eosinophilic leukemia represents a rare myeloid malignancy characterized by severe hematological complications and distinctive organ dysfunction, notably affecting the cardiovascular system. This report presents a rare case of chronic eosinophilic leukemia and Loeffler syndrome with an initial presentation of ventricular tachycardia.

Idiopathic hypereosinophilic syndromes and rare dysimmune conditions associated with hyper-eosinophilia in practice: An innovative multidisciplinary approach

Hypereosinophilic syndromes (HES) represent a group of rare dis-immune conditions characterized by blood hyper-eosinophilia and eosinophilic related burden. Especially the idiopathic subtype (I-HES) is particularly difficult to diagnose because of its heterogeneous clinical presentation, the lack of specific findings on physical exam, lab tools, and imaging informative enough to unequivocally confirm the diagnosis and the overlap with other entities, including eosinophilic organ-diseases or systemic dis-immune conditions other than I-HES (from atopy to eosinophilic granulomatosis with polyangiitis [EGPA], the last often extremely difficult to distinguish from HES). Taken together, all the features mentioned above account for an extremely difficult early recognition HES and on-time referral to a specialized centre. The referral itself is challenging due to a not univocal specialist identification, because of the variability of physicians managing HES in different settings (including allergist/clinical immunologist, haematologist, internal medicine doctors, pulmonologist, rheumatologist). Furthermore, the approach in terms of personalized treatment identification and follow-up plan (timing, organ assessment), is poorly standardized. Further translational and clinical research is needed to address the mentioned unmet needs, but on practical grounds increasing the overall clinicians' awareness on HES and implementing healthcare pathways for HES patients represent a roadmap that every clinician might try to realize in his specific setting. The present review aims at providing an overview about the current challenges and unmet needs in the practical approach to HES and rare hypereosinophilic allergo-immunological diseases, including a proposal for an innovative multidisciplinary organizational model.

Managing Patients with Hypereosinophilic Syndrome: A Statement from the Italian Society of Allergy, Asthma, and Clinical Immunology (SIAAIC)

Hypereosinophilic syndrome (HES) encompasses a heterogeneous and complex group of different subtypes within the wider group of hypereosinophilic disorders. Despite increasing research interest, several unmet needs in terms of disease identification, pathobiology, phenotyping, and personalized treatment remain to be addressed. Also, the prospective burden of non-malignant HES and, more in general, HE disorders is currently unknown. On a practical note, shortening the diagnostic delay and the time to an appropriate treatment approach probably represents the most urgent issue, even in light of the great impact of HES on the quality of life of affected patients. The present document represents the first action that the Italian Society of Allergy, Asthma, and Clinical Immunology (SIAAIC) has finalized within a wider project aiming to establish a collaborative national network on HES (InHES-Italian Network on HES) for patients and physicians. The first step of the project could not but focus on defining a common language as well as sharing with all of the medical community an update on the most recent advances in the field. In fact, the existing literature has been carefully reviewed in order to critically integrate the different views on the topic and derive practical recommendations on disease identification and treatment approaches.

Clinical and Therapeutic Intervention of Hypereosinophilia in the Era of Molecular Diagnosis

Hypereosinophilia (HE) presents with an elevated peripheral eosinophilic count of >1.5 × 109/L and is composed of a broad spectrum of secondary non-hematologic disorders and a minority of primary hematologic processes with heterogenous clinical presentations, ranging from mild symptoms to potentially lethal outcome secondary to end-organ damage. Following the introduction of advanced molecular diagnostics (genomic studies, RNA sequencing, and targeted gene mutation profile, etc.) in the last 1-2 decades, there have been deep insights into the etiology and molecular mechanisms involved in the development of HE. The classification of HE has been updated and refined following to the discovery of clinically novel markers and targets in the 2022 WHO classification and ICOG-EO 2021 Working Conference on Eosinophil Disorder and Syndromes. However, the diagnosis and management of HE is challenging given its heterogeneity and variable clinical outcome. It is critical to have a diagnostic algorithm for accurate subclassification of HE and hypereosinophilic syndrome (HES) (e.g., reactive, familial, idiopathic, myeloid/lymphoid neoplasm, organ restricted, or with unknown significance) and to follow established treatment guidelines for patients based on its clinical findings and risk stratification.

Hematological Neoplasms with Eosinophilia

Eosinophils in peripheral blood account for 0.3-5% of leukocytes, which is equivalent to 0.05-0.5 × 109/L. A count above 0.5 × 109/L is considered to indicate eosinophilia, while a count equal to or above 1.5 × 109/L is defined as hypereosinophilia. In bone marrow aspirate, eosinophilia is considered when eosinophils make up more than 6% of the total nuclear cells. In daily clinical practice, the most common causes of reactive eosinophilia are non-hematologic, whether they are non-neoplastic (allergic diseases, drugs, infections, or immunological diseases) or neoplastic (solid tumors). Eosinophilia that is associated with a hematological malignancy may be reactive or secondary to the production of eosinophilopoietic cytokines, and this is mainly seen in lymphoid neoplasms (Hodgkin lymphoma, mature T-cell neoplasms, lymphocytic variant of hypereosinophilic syndrome, and B-acute lymphoblastic leukemia/lymphoma). Eosinophilia that is associated with a hematological malignancy may also be neoplastic or primary, derived from the malignant clone, usually in myeloid neoplasms or with its origin in stem cells (myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions, acute myeloid leukemia with core binding factor translocations, mastocytosis, myeloproliferative neoplasms, myelodysplastic/myeloproliferative neoplasms, and myelodysplastic neoplasms). There are no concrete data in standardized cytological and cytometric procedures that could predict whether eosinophilia is reactive or clonal. The verification is usually indirect, based on the categorization of the accompanying hematologic malignancy. This review focuses on the broad differential diagnosis of hematological malignancies with eosinophilia.

The portrait of a stranger: the hypereosinophilic syndrome with cardiac involvement

INTRODUCTION

Hypereosinophilic syndrome is a rare clinical condition, and cardiac involvement confers a poor prognosis. Hypereosinophilic myocarditis is a medical emergency and targeted treatment should be started promptly even before a definitive diagnosis could be made.

CASE PRESENTATION

A 27-year-old female patient is hospitalized for exertional dyspnea, chest pain, and fatigue for the past 2 weeks. She also describes left leg paresthesias. Clinical examination was in normal limits. ECG showed sinus tachycardia, QS pattern in V1-V4, and diffuse flattened T waves. Laboratory tests revealed increased inflammatory markers, hypereosinophilia, elevated cardiac enzymes, high NT-proBNP. Echocardiography revealed LV dysfunction (EF 31%), while cardiac MRI showed diffuse delayed enhancement with predominant subendocardial disposition. The electromyogram was suggestive of left tibial nerve neuropathy. We interpreted the case as eosinophilic myocarditis with an urgent requirement of therapy and initiated high-dose glucocorticoid therapy and the GDMT 4-pillar heart failure treatment. We excluded common infectious, myeloproliferative syndromes, and frequent associated autoimmune diseases. With prednisone, the eosinophil count rapidly normalized and we gradually tapered the dose by 5 mg per week, however continuing with heart failure therapy. At monthly follow-up visits, there was a significant clinical improvement, with normalization of the eosinophilic count, and a near-normalization of myocardial function. The only symptom that persisted was paresthesias linked to left tibial neuropathy.

CONCLUSION

The surprisingly rapid and favorable course of the disease offers a high index of suspicion for a toxic or a reactive transitory etiology, however still unidentified. In our case, the cause of eosinophilia remained unknown, although we managed to narrow down the possible etiologies. A surprisingly good clinical response was obtained with non-specific treatment targeting mainly hyperosinophilic myocarditis.

A Rare Presentation of Hypereosinophilic Syndrome With Loffler's Endomyocarditis, Encephalopathy, and Multiple Thromboembolic Strokes

Idiopathic hypereosinophilic syndrome is a disorder with a high eosinophilic count for which no identifiable cause is evident. Herein we report a case of a 47-year-old male with a background history of hypereosinophilia, who presented with sudden onset altered level of consciousness and drowsiness for 1-day duration associated with a gradual onset progressive memory loss for 1-month duration. Based on clinical, biochemical, and imaging studies, a diagnosis of Loffler's endomyocarditis was made for which he was treated with albendazole with diethylcarbamazine along with high-dose steroids. He made a successful recovery after 2 months of treatment.

A Case of Amoxicillin-Induced Drug Reaction With Eosinophilia and Systemic Symptoms (Dress) Syndrome Associated With Significant Reactive Hypereosinophilia (HE): A Case Report

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a severe cutaneous drug reaction characterized by a skin rash, eosinophilia, atypical lymphocytosis, and involvement of multiple organs. The mortality rate of DRESS syndrome is moderate, and prompt diagnosis and treatment are essential. When DRESS syndrome is presented with significant hypereosinophilia (HE), it should be differentiated from other conditions that can cause HE through a comprehensive approach to diagnostic evaluation. Amoxicillin has been well-documented as a potential cause of DRESS syndrome. It is important to note that amoxicillin can trigger DRESS syndrome in patients who already have a known allergy to sulfasalazine, as well as when it is administered with a beta-lactamase inhibitor such as clavulanic acid. Here, we describe a case of amoxicillin alone-induced DRESS syndrome associated with significant reactive HE. A 39-year-old female presented with three days of shortness of breath, fatigue, facial swelling, and a generalized maculopapular skin rash. The patient endorsed taking amoxicillin two to three weeks prior to the presentation. Diagnostic tests revealed HE, significant generalized lymphadenopathy on computed tomography (CT) scans of the neck and abdomen, and bilateral interstitial infiltration on a CT scan of the chest suggestive of eosinophilic infiltration. Based on the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) scoring system, the case was categorized as "probable" DRESS syndrome related to amoxicillin. High-dose steroids were initiated as the treatment of choice for suspected DRESS syndrome. Other potential causes of HE were investigated and ruled out. The patient showed significant clinical improvement, with the normalization of absolute eosinophil count (AEC) and complete resolution of lung infiltrates on a repeat CT scan of the chest. The case highlights the importance of conducting a comprehensive diagnostic evaluation to differentiate DRESS syndrome from other causes of HE when significant HE is present. Prompt treatment with high-dose steroids is essential in managing patients with severe symptoms associated with DRESS syndrome. It is crucial to consider amoxicillin as a potential trigger for DRESS syndrome, even when there is no history of sulfasalazine allergy or concurrent administration of a beta-lactamase inhibitor.

Idiopathic Hypereosinophilic Syndrome: A Case Report

Idiopathic hypereosinophilic syndrome is a rare condition characterized by persistent severe eosinophilia and organ damage without any apparent cause. A 20-year-old male patient with no significant medical history was admitted to the Emergency Department with retrosternal chest pain, fatigue and asthenia. EKG showed ST elevation I, II, III, aVF, V4-V6 and blood tests showed elevated troponin levels. An echocardiogram was performed revealing severe global left ventricular systolic dysfunction. Further evaluations included cardiac magnetic resonance imaging and endomyocardial biopsy, confirming the diagnosis of eosinophilic myocarditis. The patient was started on systemic corticosteroid therapy, resulting in clinical improvement. The patient was discharged after 12 days of hospitalization, following a recovery of biventricular function and he was told to continue oral corticosteroid therapy at home. Further investigation ruled out other causes of hypereosinophilic syndromes, therefore the diagnosis of idiopathic hypereosinophilic syndrome was assumed. Despite the attempt to reduce corticosteroid therapy, the eosinophil count became elevated again, so the dosage was increased and associated with azathioprine with subsequent favorable analytical evolution. This case highlights the challenges in diagnosing and managing idiopathic hypereosinophilic syndrome and emphasizes the importance of prompt treatment initiation to prevent complications.

The multidisciplinary approach to eosinophilia

Eosinophilic granulocytes are normally present in low numbers in the bloodstream. Patients with an increased number of eosinophilic granulocytes in the differential count (eosinophilia) are common and can pose a clinical challenge because conditions with eosinophilia occur in all medical specialties. The diagnostic approach must be guided by a thorough medical history, supported by specific tests to guide individualized treatment. Neoplastic (primary) eosinophilia is identified by one of several unique acquired genetic causes. In contrast, reactive (secondary) eosinophilia is associated with a cytokine stimulus in a specific disease, while idiopathic eosinophilia is a diagnosis by exclusion. Rational treatment is disease-directed in secondary cases and has paved the way for targeted treatment against the driver in primary eosinophilia, whereas idiopathic cases are treated as needed by principles in eosinophilia originating from clonal drivers. The vast majority of patients are diagnosed with secondary eosinophilia and are managed by the relevant specialty-e.g., rheumatology, allergy, dermatology, gastroenterology, pulmonary medicine, hematology, or infectious disease. The overlap in symptoms and the risk of irreversible organ involvement in eosinophilia, irrespective of the cause, warrants that patients without a diagnostic clarification or who do not respond to adequate treatment should be referred to a multidisciplinary function anchored in a hematology department for evaluation. This review presents the pathophysiology, manifestations, differential diagnosis, diagnostic workup, and management of (adult) patients with eosinophilia. The purpose is to place eosinophilia in a clinical context, and therefore justify and inspire the establishment of a multidisciplinary team of experts from diagnostic and clinical specialties at the regional level to support the second opinion. The target patient population requires highly specialized laboratory analysis and therapy and occasionally has severe eosinophil-induced organ dysfunction. An added value of a centralized, clinical function is to serve as a platform for education and research to further improve the management of patients with eosinophilia. Primary and idiopathic eosinophilia are key topics in the review, which also address current research and discusses outstanding issues in the field.

Oral Corticosteroids for Patients with Eosinophilic Diseases: An Expert Panel View on Use, Overuse, and Strategies to Reduce Use

Severe asthma (SA), chronic rhinosinusitis with nasal polyps (CRSwNP), and eosinophilic granulomatosis with polyangiitis (EGPA) are three conditions driven by IL-5 and eosinophilic inflammation. As these conditions have high use of healthcare services, as well as lifestyle and psychological burdens, safe treatment to achieve optimal control is key. In all three conditions, as for many other eosinophilic diseases (ED), oral corticosteroids (OCS) are often used for both acute and maintenance treatment where disease activity is high. While, in general, OCS are very effective, their use is limited by a well-recognised high potential for adverse effects (AE). Moreover, cumulative exposure to OCS may not be acknowledged in many patients, especially for those predominantly treated in primary care, exposing patients to potentially damaging long-term OCS-related AEs. To discuss the use of OCS for these eosinophilic diseases, as well as to provide guidance on how to help limit their use, a board of European experts within each field was gathered. The experts completed questionnaires regarding treatment and referral pathways for patients with SA, CRSwNP, or EGPA; then, in an online meeting, discussed a number of issues in regard to OCS use. Here, the authors present the key recommendations from the expert advisory panel alongside some background to these conditions regarding treatment with OCS.