Central nervous system involvement of hypereosinophilic syndrome: A report of 10 cases and a literature review

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.

Unveiling Hypereosinophilia's Stealthy Grip on Cerebral Sinus Venous Thrombosis: A Silent Association

The report explores a case of cerebral sinus venous thrombosis associated with hypereosinophilia, presenting a unique clinical scenario. A 22-year-old male presented with persistent headache for eight days, escalating in intensity, along with projectile vomiting and blurred vision. Despite the absence of typical indicators such as fever or respiratory symptoms, comprehensive evaluations revealed hypereosinophilia in the complete blood count. Imaging studies, including magnetic resonance angiography and venography, confirmed cerebral sinus venous thrombosis. The patient was successfully treated with a multidimensional approach, including anticoagulation therapy, corticosteroids, and supportive measures. This report highlights the concealed nature of hypereosinophilia in the context of cerebral sinus venous thrombosis and underscores the importance of a vigilant diagnostic approach in unravelling this silent association.

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.

Epidemiology, clinical presentation, and outcomes of 620 patients with eosinophilia in the intensive care unit

PURPOSE

Although eosinophil-induced manifestations can be life-threatening, studies focusing on the epidemiology and clinical manifestations of eosinophilia in the intensive care unit (ICU) are lacking.

METHODS

A retrospective, national, multicenter (14 centers) cohort study over 6 years of adult patients who presented with eosinophilia ≥ 1 × 10⁹/L on two blood samples performed from the day before admission to the last day of an ICU stay.

RESULTS

620 patients (0.9% of all ICU hospitalizations) were included: 40% with early eosinophilia (within the first 24 h of ICU admission, ICU-Eo1 group) and 56% with delayed (> 24 h after ICU admission, ICU-Eo2 group) eosinophilia. In ICU-Eo1, eosinophilia was mostly due to respiratory (14.9%) and hematological (25.8%) conditions, frequently symptomatic (58.1%, mainly respiratory and cardiovascular manifestations) requiring systemic corticosteroids in 32.2% of cases. In ICU-Eo2, eosinophil-related organ involvement was rare (25%), and eosinophilia was mostly drug-induced (46.8%). Survival rates at day 60 (D60) after ICU admission were 21.4% and 17.2% (p = 0.219) in ICU-Eo1 and ICU-Eo2 patients, respectively. For ICU-Eo1 patients, in multivariate analysis, risk factors for death at D60 were current immunosuppressant therapy at ICU admission, eosinophilia of onco-hematological origin and the use of vasopressors at ICU admission, whereas older age and the use of vasopressors or mechanical ventilation at the onset of eosinophilia were associated with a poorer prognosis for ICU-Eo2 patients.

CONCLUSION

Eosinophilia ≥ 1 × 10⁹/L is not uncommon in the ICU. According to the timing of eosinophilia, two subsets of patients requiring different etiological workups and management can be distinguished.

An unusual neurological presentation in a patient with primary hypereosinophilic syndrome

Hypereosinophilic syndromes are characterized by an increased number of blood eosinophils (usually more than 1.5 × 10⁹) infiltrating tissues and causing organ damage through over-production of pro-inflammatory cytokines with heterogeneous clinical presentation. Here we present a case of a 47 years old male, with an unremarkable previous medical history, with a sudden onset of subungual hemorrhage and low back pain. Admitted for right arm weakness and vomiting, was raised the suspicion of acute cerebrovascular syndrome, but a brain CT scan with angiogram and perfusion sequences did not show any signs of early ischaemic lesions; conversely, lab tests revealed an increased peripheral eosinophil blood count. Clinical conditions rapidly worsened and a brain MRI showed multiple sub-acute ischaemic lesions compatible with vasculitis while EEG was in favor of widespread cortical distress. Diagnosis of the hypereosinophilic syndrome was made through peripheral blood smear and osteo-medullar biopsy, which showed a rich prevalence of eosinophils. The molecular biology testing showed FIP1L1-PDGRA gene mutation. Despite the prompt therapy beginning with intravenous corticosteroids and tyrosine-kinase inhibitors with normalization of cell blood count in a few days, the patient remained in minimal consciousness. When facing unusual symptoms onset (low back pain with weakness in one limb) and a highly impaired WBC not consistent with other courses (such as infections, vasculitis, allergies, and other diseases involving the immune system) clinicians should take into account the possibility of a hematological disorder and treat it as soon as possible to avoid a poor prognosis.

Literature reviews of stroke with hypereosinophilic syndrome

Hypereosinophilic syndrome (HES) is defined by persistently elevated blood eosinophil levels and is associated with evidence of organ damage. Cardiovascular involvement in HES is most commonly associated with Loffler endocarditis (cardiac HES). Cardiac HES is typically characterized by progressive subendocardial fibrosis with overlying mural thrombus formation, leading to restrictive dysfunction of the left ventricle. The thrombus from cardiac HES could result in cardiogenic stroke; however, most of the stroke cases with HES were not associated with huge thromboembolism rather multiple infarcts in the watershed area. The major clinical features of 97 previously reported cases of stroke with HES are as follows: the median age was 52 years, of which 61 (63%) were men; the initial presenting symptoms were neurological (73%), followed by headache (16%), respiratory symptoms (9%), and visual symptoms (9%). Almost half of the cases were diagnosed with cardiac HES. The characteristics of cardiac findings were mural thrombi, endomyocardial fibrosis, and a restrictive pattern of heart failure. Cerebral findings revealed 78 cases (80%) were described as multiple infarctions and 55 cases (57 %) were involved with watershed areas, whereas 11 cases (11％) were described as embolic stroke for one proximal large-vessel occlusion. Regarding treatment, 71 (73%), 28 (29%), and 16 (16%) patients were treated with steroids, anticoagulants, and antiplatelets, respectively. The overall mortality and recovery rates were 11% and 89%, respectively. Physicians should know most cases of stroke with HES are characterized by multiple infarctions in the watershed area, and cardiac HES is not always associated with stroke.

Hypereosinophilia with cerebral venous sinus thrombosis and intracerebral hemorrhage: A case report and review of the literature

BACKGROUND

Hypereosinophilia (HE) is defined as a peripheral blood eosinophil count of > 1.5 × 10⁹/L and may be associated with tissue damage. The clinical presentations of HE vary; however, myocardial fibrosis and thrombosis can threaten the lives of patients with sustained eosinophilia. Cerebral venous sinus thrombosis (CVST) in the setting of eosinophil-related diseases has seldom been reported. Here, we review the literature on HE with CVST to increase knowledge and encourage early diagnosis.

CASE SUMMARY

A previously healthy 41-year-old man was admitted to hospital with diarrhea and abdominal pain. He was treated with antibiotics for suspected acute colitis. Three days later, he experienced headache and vomiting. Brain computed tomography (CT) revealed thrombosis of the left jugular vein to the left transverse sinus vein. Platelet (PLT) count decreased to 60 × 10¹²/L, and absolute eosinophil count (AEC) increased to 2.41 × 10⁹/L. He was treated with low-molecular-weight heparin. PLT count progressively decreased to 14 × 10⁹/L, and we terminated anticoagulation and performed PLT transfusion. Six days after admission, he complained of a worsening headache. Brain CT revealed right temporal lobe and left centrum semiovale intracerebral hemorrhage, and AEC increased to 7.65 × 10⁹/L. We used prednisolone for HE. The level of consciousness decreased, so emergency hematoma removal and decompressive craniectomy for right cerebral hemorrhage were performed. The patient was alert 2 d after surgery. He was treated with anticoagulation again 2 wk after surgery. Corticosteroids were gradually tapered without any symptomatic recurrence or abnormal laboratory findings.

CONCLUSION

HE can induce CVST, and we need to focus on eosinophil counts in patients with CVST.

Potent Anti-Inflammatory Effects of Tetracyclines on Human Eosinophils

Eosinophils are potent pro-inflammatory cells. Not only in allergic diseases but also in other diseases there is a need for treatment strategies to induce resolution of eosinophil-mediated inflammation. During the last years beneficial non-antibiotic activities of tetracyclines (TCNs) have been shown in different diseases in which eosinophils play a role, for example, asthma and bullous pemphigoid. The working mechanism of these effects remains to be clarified. Aim of the present study was to investigate the effects of TCNs on eosinophils. Flow cytometry analysis of apoptosis, mitochondrial membrane potential, activation of caspases, intracellular H₂O₂ and calcium, surface expression of eosinophil activation markers was performed in highly purified peripheral blood eosinophils of non-atopic donors. Tetracycline hydrochloride, minocycline and doxycycline significantly induced eosinophil apoptosis. All TCNs were able to significantly overcome the strong survival enhancing effects of pro-eosinophilic cytokines and staphylococcus aureus enterotoxins. Tetracycline hydrochloride induced eosinophil apoptosis was accompanied by intracellular production of hydrogen peroxide, loss of mitochondrial membrane potential and activation of caspases. Moreover, tetracycline hydrochloride significantly down regulated eosinophil surface expression of CD9 and CD45, and of the activation markers CD11b and CD69, but not of CD54, CD63, or CD95. Our data, propably for the first time, point to a potent anti-inflammatory role of TCNs on eosinophils.

FIP1L1-PDGFRA-Associated Hypereosinophilic Syndrome as a Treatable Cause of Watershed Infarction

BACKGROUND AND PURPOSE

Ischemic stroke has been reported in various conditions associated with eosinophilia. FIP1L1-PDGFRA fusion ([Fip1-like 1-platelet-derived growth factor receptor alpha]; F/P) leads to the proliferation of the eosinophilic lineage and thus to a clonal hypereosinophilic syndrome that is highly responsive to imatinib.

METHODS

We previously reported on a nationwide retrospective study of 151 patients with F/P-associated clonal hypereosinophilic syndrome. Patients from this cohort with a clinical history of ischemic stroke (as well as 2 additional cases) were further analyzed to better define their clinical picture and outcomes.

RESULTS

Sixteen male patients (median age, 51 [43-59] years) with low-to-intermediate cardiovascular risk were included. Median National Institutes of Health Stroke Scale was 4 (range, 1-6). Most cerebral imaging disclosed multiple bilateral infarctions of watershed distribution (69%). Despite frequent cardiac involvement (50%), cardiac thrombus was evidenced in a single patient and, according to the TOAST classification (Trial of ORG 10172 in Acute Stroke Treatment), 62.5% of strokes were presumably of undetermined etiology. Among the 15 patients treated with imatinib, and after a median follow-up of 4.5 years, stroke recurred in only 3 patients (consisting of either cardio embolic or hemorrhagic events, unrelated to the first episode).

CONCLUSIONS

F/P+ clonal hypereosinophilic syndrome is a diagnosis to consider in patients with unexplained ischemic stroke and hypereosinophilia (especially in the setting of multiple cortical borderzone distribution) and warrants prompt initiation of imatinib.

Neurologic complications of myocarditis

Myocarditis, a nonischemic acquired cardiomyopathy, is an uncommon condition with multiple presentation patterns which may be initially difficult to recognize and may simulate other conditions such as acute myocardial infarction, pericarditis, septicemia, etc. There are four distinct clinical presentation patterns that include: (1) low-grade nonspecific symptoms such as fatigue; (2) symptoms that resemble an acute myocardial infarction, especially in younger individuals; (3) a heart failure presentation which may be acute, subacute, or chronic and may be associated with cardiac conduction system defects and arrhythmias; and (4) an arrhythmia presentation that may produce sudden cardiac death, especially in young athletes with minimal or no prodromal symptoms. This chapter will provide a brief overview of various myocarditis etiologies and diagnostic modalities. The ultimate focus will be directed toward neurologic manifestations of myocarditis and its subtypes, complications of specific therapies including extracorporeal membrane oxygenation (ECMO) for refractory heart failure, and review the current literature regarding the appropriate use of therapeutic anticoagulation in myocarditis and heart failure for stroke prevention. Covid-19 infection has been discovered to cause myocarditis. The emerging science will be discussed. Nuances of brain death (BD) determination in patients receiving venoarterial ECMO for heart failure refractory to standard medical therapies will be discussed.

Central Nervous System and Cardiac Involvement in the Hypereosinophilic Syndrome: A Case Report

Hypereosinophilic syndrome is a rare entity and heterogeneous group of disorders characterized by hypereosinophilia and organ involvement. In this study, we presented a 49-year-old woman with cardiac tamponade in the context of Hypereosinophilic syndrome. Identifying hypereosinophilia as the underlying cause can have tremendous clinical implications for rapid initiation of appropriate treatment to minimize further end organ damage.

Non-hematologic diagnosis of systemic mastocytosis: Collaboration of radiology and pathology

Systemic mastocytosis (SM) is a hematologic disease with a wide range of clinical courses ranging from an indolent condition with normal life expectancy to exceedingly aggressive disorder with a poor prognosis. The symptoms and signs of SM result from the release of mast cell mediators with heterogeneous functions, and/or organ damage from neoplastic mast cell infiltration, or both. Diagnostic criteria for SM are well-defined by the World Health Organization (WHO). However, the diagnosis of SM can be difficult when especially it is not in the differential diagnosis. Routinely used radiologic techniques (e.g., X-ray, ultrasound, CT scans can show findings such as lytic-, sclerotic- or mixed-bone lesions, splenomegaly, hepatomegaly, retroperitoneal or periportal mesenteric lymphadenopathy, and omental thickening). It is essential to emphasize that the constellation of these radiologic findings should strongly concern of SM, especially in patients who also have a skin rash, allergic reactions, gastrointestinal tract symptoms (lasting, intermittent nausea, diarrhea), paroxysmal tachycardias, unexplained weight loss, persistent bone pain, cytopenias, liver dysfunction, eosinophilia. These findings, even coincidentally noted, will likely lead to a tissue biopsy, which reveals diagnosis (as we discussed and illustrated some tissue biopsies here). Moreover, the role of MRI and new techniques such as [18-fluorodeoxyglucose positron emission computed tomography, fibroscan] in the diagnosis of SM have been discussed. Furthermore, we reviewed the use of radiologic methods to evaluate treatment response and prognostication of SM..

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.