Diagnosis
In eosinophilic myocarditis, echocardiography typically gives non-specific and only occasional findings of endocardium thickening, left ventricular hypertrophy, left ventricle dilation, and involvement of the mitral and/or tricuspid valves. However, in acute necrotizing eosinophilic myocarditis, echocardiography usually gives diagnostically helpful evidence of a non-enlarged heart with a thickened and poorly contracting left ventricle. Gadolinium-based cardiac magnetic resonance imaging is the most useful non-invasive procedure for diagnosing eosinophilic myocarditis. It supports this diagnosis if it shows at least two of the following abnormalities: a) an increased signal in T2-weighted images; b) an increased global myocardial early enhancement ratio between myocardial and skeletal muscle in enhanced T1 images and c) one or more focal enhancements distributed in a non-vascular pattern in late enhanced T1-weighted images. Additionally, and unlike in other forms of myocarditis, eosinophilic myocarditis may also show enhanced gadolinium uptake in the sub-endocardium. However, the only definitive test for eosinophilic myocarditis is cardiac muscle biopsy showing the presence of eosinophilic infiltration. Since the disorder may be patchy, multiple tissue samples taken during the procedure improve the chances of uncovering the pathology but in any case, negative results do not exclude the diagnosis. Eosinophilic coronary periarteritis
Eosinophilic coronary periarteritis is an extremely rare heart disorder caused by extensive eosinophilic infiltration of the adventitia and periadventitia, i.e. the soft tissues, surrounding the coronary arteries. The intima, tunica media, and tunica intima layers of these arteries remain intact and are generally unaffected.
Perhaps less commonly, eosinophilic myocarditis, eosinophilic thrombotic myocarditis, and eosinophilic fibrotic myocarditis are viewed as three separate but sequentially linked disorders in a spectrum of disorders termed eosinophilic cardiac diseases. The focus here is on eosinophilic myocarditis as a distinct disorder separate from its thrombotic and fibrotic sequelae. Eosinophilic myocarditis is a rare disorder. It is usually associated with, and considered secondary to, an underlying cause for the pathological behavior of the eosinophils such a toxic reaction to a drug (one of its more common causes in developed nations), the consequence of certain types of parasite and protozoan infections (a more common cause of the disorder in areas with these infestations), or the result of excessively high levels of activated blood eosinophils due to a wide range of other causes. The specific treatment (i.e. treatment other than measures to support the cardiovascular system) of eosinphilic myocarditis differs from the specific treatment of other forms of myocarditis in that it is focused on relieving the underlying reason for the excessively high numbers and hyperactivity of eosinophils as well as on inhibiting the pathological actions of these cells. Signs and symptoms
Symptoms in eosinophilic myocarditis are highly variable. They tend to reflect the many underlying disorders causing eosinophil dysfunction as well as the widely differing progression rates of cardiac damage. Before cardiac symptoms are detected, some 66% of cases have symptoms of a common cold and 33% have symptoms of asthma, rhinitis, urticarial, or other allergic disorder.