Acute eosinophilic myocarditis: diagnosis and treatment

Eosinophilic myocarditis: systematic review

OBJECTIVE

In clinical practice, patients with eosinophilic myocarditis (EM) may forgo the gold standard diagnostic procedure, endomyocardial biopsy (EMB), although it is highly recommended in guidelines. This systematic review aims to summarise current approaches in diagnosing and treating EM with a particular emphasis on the utilisation and value of alternative diagnostic methods.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, we searched MEDLINE and EMBASE for all peer-reviewed articles using the keywords "eosinophilic myocarditis" from their inception to 10 September 2022.

RESULTS

We included 239 articles, including 8 observational studies and 274 cases, in this review. The median patient age was 45 years. Initial presentations were non-specific, including dyspnoea (50.0%) and chest pain (39.4%). The aetiologies of EM were variable with the most common being idiopathic (28.8%) and eosinophilic granulomatosis polyangiitis (19.3%); others included drug-induced (13.1%) and hypereosinophilic syndrome (12.8%). 82.4% received an EM diagnosis by EMB while 17.6% were diagnosed based on clinical reasoning and cardiac MRI (CMR). CMR-diagnosed patients exhibited a better risk profile at diagnosis, particularly higher left ventricular ejection fraction and less need for inotropic or mechanical circulatory supports. Glucocorticoids were the primary treatment with variability in dosages and regimens.

CONCLUSION

EMB is the mainstay for diagnostic testing for EM. CMR is potentially helpful for screening in appropriate clinical scenarios. Regarding treatment, there is no consensus regarding the optimal dosage of corticosteroids. Large clinical trials are warranted to further explore the utility of CMR in the diagnosis of EM and steroid regimen in treating EM.

Cardiac Magnetic Resonance Imaging Used to Determine a Rare Etiology of a Layered Left Ventricular Apical Thrombus

Eosinophilic myocarditis (EM) is a rare disease, often associated with hypereosinophilic syndrome (HES). Historically, the diagnostic gold standard was endomyocardial biopsy (EMB). We present a unique case of a 58-year-old female who presents after a syncopal episode and was found to have a layered left ventricular (LV) thrombus. Using laboratory studies and cardiac magnetic resonance imaging (MRI), we were able to delineate the etiology, avoiding any invasive testing.

Hypereosinophilic syndrome presenting as acute ischemic stroke, myocardial infarction, and arterial involvement: A case report

BACKGROUND

Simultaneous cerebral and myocardial infarction with arterial involvement has not been reported in hypereosinophilic syndrome (HES). Here, we report a patient with HES that was also associated with acute ischemic stroke, myocardial infarction, and arterial involvement of the left common carotid artery, vertebral arteries, posterior cerebral artery, and coronary artery.

CASE SUMMARY

A 64-year-old male patient was admitted with headache and right lower extremity weakness. Laboratory tests indicated eosinophilia. Brain magnetic resonance imaging (MRI) showed bilateral and multiple acute infarcts in the border zones. Electrocardiography revealed that T wave was inverted and that the concentration of troponin I was significantly elevated above normal levels. Cardiac echocardiography showed an ejection fraction of 69% with mitral and tricuspid mild regurgitation. Computed tomography angiography detected multiple and localized instances of mild stenosis in the left common carotid artery bifurcation, bilateral vertebral arteries (V5 segment), and the posterior cerebral artery (P2 segment). These were observed together with multiple non-calcified and mixed plaques as well as luminal stenosis in the left circumflex artery, left anterior descending artery, and right coronary artery. The patient was treated with oral methylprednisolone and clopidogrel, after which the absolute eosinophil count fell rapidly to a normal level. After one month, a second brain MRI showed a partial reduction in the size and number of the lesions.

CONCLUSION

HES can masquerade as ischemic stroke, myocardial infarction, and arterial vascular involvement. The patient reported here recovered very quickly when his eosinophil blood count returned to normal. Early diagnosis and rapid reduction of eosinophils may lead to a good prognosis.

Complete resolution of severe secondary mitral regurgitation accompanying eosinophilic myocarditis due to immunosuppressive treatment

Eosinophilic myocarditis (EM) is an under-diagnosed inflammatory heart disease that often leads to severe left ventricular (LV) dysfunction. Meanwhile, severe secondary mitral regurgitation (MR) with valve disruption, possibly requiring mitral valve repair, is rarely concomitant with EM. We present the case of a 64-year-old female diagnosed with heart failure with severe LV dysfunction and localized asynergy. Echocardiography revealed severe secondary MR with mitral valve disruption. Cardiac magnetic resonance imaging (CMR) showed transmural late-gadolinium enhancement localized in the anterior wall and diffuse high-signal areas on T2-weighted images, suggesting non-ischemic and inflammatory heart disease. Although the peripheral eosinophil count was not elevated on admission, it gradually increased during hospitalization. These findings encouraged us to perform endomyocardial biopsy, which confirmed myocardial eosinophilic infiltration with mild fibrosis and necrosis, leading to the diagnosis of EM. Immunosuppressive treatment with oral corticosteroids improved LV dysfunction and completely resolved severe secondary MR. The current case highlighted that comprehensive assessment of laboratory, imaging, and pathological examinations including CMR is crucial to develop the appropriate therapeutic strategy for refractory heart failure. Immunosuppressive treatment should be considered as the first therapeutic option even in EM cases with severe secondary MR, possibly requiring mitral valve repair.

<Learning objective:The gradual increase in peripheral eosinophils during hospitalization, without significant peripheral eosinophilia on admission, is crucial for the diagnosis of eosinophilic myocarditis. Comprehensive assessment of laboratory, imaging, and pathological examinations including cardiac magnetic resonance imaging is mandatory when building an appropriate therapeutic strategy for refractory heart failure. Severe secondary mitral regurgitation with mitral valve disruption can be completely resolved via immunosuppressive treatment in cases of eosinophilic myocarditis.>

Eosinophilic Myocarditis in a Patient With Sickle Cell Disease

A 23-year-old man with sickle cell disease treated with splenectomy and allogenic stem cell transplantation presented with recurrent chest pain, elevated cardiac enzymes, and unremarkable electrocardiography. His work-up revealed eosinophilia, raising concern for eosinophilic myocarditis. Cardiac magnetic resonance imaging showed patchy late gadolinium enhancement of the left ventricular free wall, suggestive of myocarditis. He was treated with high-dose intravenous steroids followed by oral prednisone, with improvement in his symptoms and eosinophilia and a decrease in cardiac enhancement on follow-up imaging. (Level of Difficulty: Intermediate.)

Elusive Diagnosis of Eosinophilic Myocarditis: A Case Series

We present 2 relevant cases of eosinophilic myocarditis (EM) in patients that presented with cardiogenic shock, one of whom received a durable ventricular assist device followed by heart transplantation, with the diagnosis of EM being made based on analysis of the excisional biopsy obtained during implantation of the ventricular assist device. The second patient was initially misdiagnosed with peripartum cardiomyopathy and underwent abortion, to later being diagnosed with EM through endomyocardial biopsy. These two cases highlight the importance of high clinical suspicion for EM based on eosinophilia, comorbidities, and presentation, as well as the value of early diagnosis and therapeutic interventions, including corticosteroids, and advanced heart failure therapies, such as mechanical circulatory support and heart transplantation.

Myocarditis and Eosinophilia: Three Cases of Hypereosinophilic Syndrome and Myocarditis

Eosinophilic infiltration is a rare and underrecognized cause of myocarditis associated with prolonged eosinophilia. Before advanced imaging and routine biopsy, patients were diagnosed with an idiopathic cardiomyopathy with subsequent diagnosis made on autopsy. We present 3 cases of eosinophilic myocarditis diagnosed by cardiac biopsy classified as hypereosinophilic syndrome. Two patients presented with severe left ventricular dysfunction, and 1 patient presented with cardioembolic stroke. All patients were successfully treated with glucocorticoid therapy. Our cases highlight the importance of early diagnosis with endomyocardial biopsy and prompt immunosuppressive treatment.

A young female presenting with heart failure secondary to eosinophilic myocarditis: a case report and review of the literature

Background

Eosinophilic myocarditis is one of the fatal complications of idiopathic hypereosinophilic syndromes. Given the rarity of this form of myocarditis, it is often under-recognized. We describe a young girl who presented with features of heart failure. To our knowledge, this is the first reported case of eosinophilic myocarditis in a young Sri Lankan female.

Case presentation

A previously healthy 21 year old Sri Lankan female admitted with shortness of breath for 1 week duration with associated low grade fever and profuse sweating. She was mildly febrile and dyspnoeic with absent ankle oedema. She was tachycardic and had elevated Jugular venous pressure with negative Kussmaul sign. Blood pressure was 100/70 mmHg. Clinically there was no cardiomegaly and heart sounds were slightly muffled with gallop rhythm. Bilateral basal fine end inspiratory crackles and mild hepatosplenomegaly were noted. The laboratory examinations showed leucocytosis with severe eosinophilia with no abnormal cells. Her ESR, Troponin I and Brain natriuretic peptide were elevated with normal CRP and electrocardiogram showed sinus tachycardia with wide spread ST depression. Heart failure was evident on chest X-ray and 2D-echocardiogram showed global left ventricular hypokinesia with 40% ejection fraction and a thin layer of pericardial effusion. Mild hepatosplenomegaly without lymphadenopathy was detected in the ultrasound scan. Bone marrow biopsy showed hypereosinophilia with no evidence of bone marrow infiltration. FIP1L1–PDGFRA fusion transcript and BCR–ABL transcript were not detected. Secondary causes for hypereosinophilia were excluded and the diagnosis of idiopathic hypereosinophilic syndrome and eosinophilic myocarditis was made. She had good response to steroids clinically and biochemically with complete recovery of left ventricular function. She is now on steroid to be continued at least 6 months to 1 year.

Conclusion

Eosinophilic myocarditis is a rare but fatal disease if left untreated. Hence clinicians should have high index of suspicion to diagnose eosinophilic myocarditis in clinical context of heart failure due to myocarditis. The diagnoses of eosinophilic myocarditis may often be challenged especially in a poor recourse setting. However available investigation should be used to diagnose this condition without delay. Early treatment with systemic steroids may prevent fatal outcome and therapies for this disease have yet to be validated in large prospective studies.

Eosinophilic myocarditis: characteristics, diagnostics and outcomes of a rare condition

Eosinophilic myocarditis is a rare and potentially fatal condition characterised by eosinophilic inflammatory infiltration of myocardium. We report seven consecutive cases of eosinophilic myocarditis at our centre and discuss the important characteristics, investigation and management of this disease.

Early-Stage Loeffler's Endocarditis with Isolated Right Ventricular Involvement: Management, Long-Term Follow-Up, and Review of Literature

Loeffler's endocarditis is a clinical condition characterized by combination of three key findings: unexplained prolonged and marked eosinophilia (>1500 eosinophils/mm(3) ), absence of a primary cause of hypereosinophilia, and evidence of eosinophil-mediated organ damage. We report a case of a 55-year-old African American male with symptoms of heart failure. Hematology showed white blood cell count of 17 670/mm(3) with 63% eosinophils and an absolute eosinophil count of 11 133/mm(3) . Echocardiogram and computed tomography showed near complete obliteration of right ventricular cavity. Endomyocardial biopsy showed diffuse myocyte necrosis with extensive eosinophilic infiltration without fibrosis consistent with early Loeffler's endocarditis. Molecular and cytogenetic analyses of bone marrow cells were negative for FIP1L1-PDGFRA fusion, PDGFRB mutation, abnormal myeloid maturation, or a lymphoproliferative disorder. Flow cytometry showed no clonality excluding chronic eosinophilic leukemia. There was a complete resolution of symptoms and eosinophilia after 1 month of steroid therapy.

Eosinophilic Myocarditis due to Toxocariasis: Not a Rare Cause

Myocarditis is a clinically important disease because of the high mortality. From the perspective of treatment strategy, eosinophilic myocarditis should be distinguished from other types of myocarditis. Toxocariasis, caused by Toxocara canis or Toxocara cati, is known as a cause of eosinophilic myocarditis but is considered rare. As it is an unpopular disease, eosinophilic myocarditis due to toxocariasis may be underdiagnosed. We experienced two cases of eosinophilic myocarditis due to toxocariasis from different geographical areas in quick succession between 2013 and 2014. Case 1 is 32-year-old man. Case 2 is 66-year-old woman. In both cases, diagnosis was done by endomyocardial biopsy and IgG-ELISA against Toxocara excretory-secretory antigen. Only a corticosteroid was used in Case  1, whereas a corticosteroid and albendazole were used in Case  2 as induction therapy. Both patients recovered. Albendazole was also used in Case  1 to prevent recurrence after induction therapy. Eosinophilic myocarditis by toxocariasis may in actuality not be a rare disease, and corticosteroid is an effective drug as induction therapy even before use of albendazole.

Natural killer cells limit cardiac inflammation and fibrosis by halting eosinophil infiltration

Myocarditis is a leading cause of sudden cardiac failure in young adults. Natural killer (NK) cells, a subset of the innate lymphoid cell compartment, are protective in viral myocarditis. Herein, we demonstrated that these protective qualities extend to suppressing autoimmune inflammation. Experimental autoimmune myocarditis (EAM) was initiated in BALB/c mice by immunization with myocarditogenic peptide. During EAM, activated cardiac NK cells secreted interferon γ, perforin, and granzyme B, and expressed CD69, tumor necrosis factor-related apoptosis-inducing ligand treatment, and CD27 on their cell surfaces. The depletion of NK cells during EAM with anti-asialo GM1 antibody significantly increased myocarditis severity, and was accompanied by elevated fibrosis and a 10-fold increase in the percentage of cardiac-infiltrating eosinophils. The resultant influx of eosinophils to the heart was directly responsible for the increased disease severity in the absence of NK cells, because treatment with polyclonal antibody asialogangloside GM-1 did not augment myocarditis severity in eosinophil-deficient ΔdoubleGATA1 mice. We demonstrate that NK cells limit eosinophilic infiltration both indirectly, through altering eosinophil-related chemokine production by cardiac fibroblasts, and directly, by inducing eosinophil apoptosis in vitro. Altogether, we define a new pathway of eosinophilic regulation through interactions with NK cells.

Eosinophilic myocarditis: two case reports and review of the literature

Background

Eosinophilic myocarditis is a rare and often under-diagnosed subtype of myocarditis with only around 30 cases published in the medical literature. In this article we present two patients with eosinophilic myocarditis with the aim to demonstrate the often elusive nature of the disease and present the current scientific literature on this topic.

Case presentation

A 76 years old Caucasian gentleman and a 36 years old Aboriginal gentleman both presenting with heart failure symptoms were eventually diagnosed with eosinophilic myocarditis after extensive evaluation. Their presentation, assessment, and medical management is explored in this article.

Conclusions

Eosinophilic myocarditis remains a rare and likely under-diagnosed subtype of myocarditis. The key features of this disease include myocardial injury in the setting of non-contributory coronary artery disease. Endomyocardial biopsy remains the definitive gold standard for diagnosis of noninfectious eosinophilic myocarditis. Non-invasive cardiac imaging in the setting of peripheral eosinophilia can be strongly suggestive of eosinophilic myocarditis with potential for earlier diagnosis. Failure to diagnose eosinophilic myocarditis and the delay of therapy may lead to irreversible myocardial injury. Therapies for this disease have yet to be validated in large prospective studies.

Fatal eosinophilic myocarditis develops in the absence of IFN-γ and IL-17A

CD4(+) T cells play a central role in inflammatory heart disease, implicating a cytokine product associated with Th cell effector function as a necessary mediator of this pathophysiology. IFN-γ-deficient mice developed severe experimental autoimmune myocarditis (EAM), in which mice are immunized with cardiac myosin peptide, whereas IL-17A-deficient mice were protected from progression to dilated cardiomyopathy. We generated IFN-γ(-/-)IL-17A(-/-) mice to assess whether IL-17 signaling was responsible for the severe EAM of IFN-γ(-/-) mice. Surprisingly, IFN-γ(-/-)IL-17A(-/-) mice developed a rapidly fatal EAM. Eosinophils constituted a third of infiltrating leukocytes, qualifying this disease as eosinophilic myocarditis. We found increased cardiac production of CCL11/eotaxin, as well as Th2 deviation, among heart-infiltrating CD4(+) cells. Ablation of eosinophil development improved survival of IFN-γ(-/-)IL-17A(-/-) mice, demonstrating the necessity of eosinophils in fatal heart failure. The severe and rapidly fatal autoimmune inflammation that developed in the combined absence of IFN-γ and IL-17A constitutes a novel model of eosinophilic heart disease in humans. This is also, to our knowledge, the first demonstration that eosinophils have the capacity to act as necessary mediators of morbidity in an autoimmune process.

IL-33 independently induces eosinophilic pericarditis and cardiac dilation: ST2 improves cardiac function

BACKGROUND

IL-33 through its receptor ST2 protects the heart from myocardial infarct and hypertrophy in animal models but, paradoxically, increases autoimmune disease. In this study, we examined the effect of IL-33 or ST2 administration on autoimmune heart disease.

METHODS AND RESULTS

We used pressure-volume relationships and isoproterenol challenge to assess the effect of recombinant (r) IL-33 or rST2 (eg, soluble ST2) administration on the development of autoimmune coxsackievirus B3 myocarditis and dilated cardiomyopathy in male BALB/c mice. The rIL-33 treatment significantly increased acute perimyocarditis (P=0.006) and eosinophilia (P=1.3×10(-5)), impaired cardiac function (maximum ventricular power, P=0.0002), and increased ventricular dilation (end-diastolic volume, P=0.01). The rST2 treatment prevented eosinophilia and improved heart function compared with rIL-33 treatment (ejection fraction, P=0.009). Neither treatment altered viral replication. The rIL-33 treatment increased IL-4, IL-33, IL-1β, and IL-6 levels in the heart during acute myocarditis. To determine whether IL-33 altered cardiac function on its own, we administered rIL-33 to undiseased mice and found that rIL-33 induced eosinophilic pericarditis and adversely affected heart function. We used cytokine knockout mice to determine that this effect was due to IL-33-mediated signaling but not to IL-1β or IL-6.

CONCLUSIONS

We show for the first time to our knowledge that IL-33 induces eosinophilic pericarditis, whereas soluble ST2 prevents eosinophilia and improves systolic function, and that IL-33 independently adversely affects heart function through the IL-33 receptor.