Eosinophilic myocarditis: two case reports and review of the literature

Abstract

BackgroundEosinophilic 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 presentationA 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.ConclusionsEosinophilic 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.

A Pitfall in the Diagnosis of Eosinophilic Myocarditis in a Patient who Received Steroid Therapy

“…Eosinophilic myocarditis is a rare form of myocarditis characterized by diffuse or focal myocardial inflammation with eosinophilic infiltration (10). While eosinophilia is often observed in peripheral blood samples, a definite diagnosis requires evidence of eosinophilic infiltration in the myocardium (11).…”

“…While eosinophilia is often observed in peripheral blood samples, a definite diagnosis requires evidence of eosinophilic infiltration in the myocardium (11). However, since eosinophilic infiltration sometimes only affects the focal myocardium, the sensitivity of endomyocardial biopsy is insufficient (approximately 50%) (2,10). Positron emission tomography (PET) and gallium scintigraphy have been reported to be useful as non-invasive modalities for diagnosing eosinophilic myocarditis (5,10).…”

“…However, since eosinophilic infiltration sometimes only affects the focal myocardium, the sensitivity of endomyocardial biopsy is insufficient (approximately 50%) (2,10). Positron emission tomography (PET) and gallium scintigraphy have been reported to be useful as non-invasive modalities for diagnosing eosinophilic myocarditis (5,10). Thus, these non-invasive modalities can help in the diagnosis of eosinophilic myocarditis, especially when the results of an endomyocardial biopsy are inconclusive.…”

Acute peri-myocarditis with an unusual initial manifestation of gallbladder edema and a profound eosinophilic surge during convalescence

“…Acute myocarditis is defined as cardiac inflammation that commonly results from an infectious process or hypersensitivity to drugs 1) . Because acute myocarditis presents various vague symptoms or findings ranging from an asymptomatic state shown only by abnormalities on an electrocardiogram to cardiac sudden death 1 -6) or often shows no significance in the physical examination 1) , early diagnosis of acute myocarditis is challenging 2,5,7) .…”

Myocarditis Mimicking Acute Coronary Syndrome Secondary to Eosinophilia

“…X syndrome is defined as an absolute eosinophil count greater than 1.5 × 109/L lasting for more than six months in the absence of any known cause of hypereosinophilia with evidence of organ involvement. Cardiac disease is the major cause of morbidity and mortality in patients with this syndrome, occurring in about 50% of patients with idiopathic hypereosinophilic syndrome [1,2]. EM can present with a wide range of symptoms and can easily be missed or diagnosed late.…”