clinical presentations vary from nonspecific systemic symptoms ( e.g. , fever , myalgia , palpitation , chest pain , dyspnea ) to fulminant hemodynamic collapse and sudden death .
infections ( viral , bacterial , fungal , protozoal , parasitic ) , toxins , immunological syndromes , and hypersensitivity can cause myocarditis . among these
lewin et al .   reported that seven explanted hearts from 288 heart transplants ( 2.4% ) had histological evidence of hypersensitivity myocarditis .
unlike other forms of myocarditis , the prognosis of hypersensitivity myocarditis is excellent , usually improving after administration of the causative drug is ceased .
, we report a case of hypersensitivity myocarditis , as confirmed by cardiac magnetic resonance imaging ( cmr ) and endomyocardial biopsy ( emb ) , which subsequently improved after cessation of the causative drug and administration of prednisolone .
she had a history of hypertension , transient cerebral ischemic attack , and osteoarthritis in both knees .
her blood pressure was 91/53 mmhg , pulse rate was 63 beats per minute , respiration rate was 20 breaths per minute , and body temperature was 37. upon physical examination , heart sounds were normal without murmur .
multiple itchy erythematous lesions were present on the hands , buttocks , abdomen , and trunk ( fig .
the results of laboratory examinations were as follows : white blood cell count , 9,140/mm ; eosinophil count , 1,380/mm ; hemoglobin , 10.3 g / dl ; platelet count , 123,000/mm ; c - reactive protein level , 1.7 mg / dl ; and erythrocyte sedimentation rate , 72 mm / sec . the levels of brain natriuretic peptide , creatine kinase - mb ( ck - mb ) , and troponin - i were 944 pg / ml , 56.73 ng / ml , and 38.85 ng / ml , respectively .
initial electrocardiography showed st segment elevation  1 mm in leads ii , iii , avf , v5 , and v6 ( fig .
emergency coronary angiography was performed under the assumption of acute st segment elevation myocardial infarction at the inferolateral wall , but coronary atherosclerosis was not evident .
echocardiography showed the " sparkling " appearance of the left ventricular ( lv ) myocardium , concentric lv hypertrophy , and mild hypokinesia on the anterior , anterolateral , and posterior walls from the mid - lv to the apex with 50% lv ejection fraction .
peripheral blood eosinophilia , skin rash , and a history of taking multiple medications suggested hypersensitivity myocarditis .
3 . management of heart failure using aldosterone and furosemide was initiated promptly . on the second day of hospital admission
, however , dyspnea worsened , and newly developed bilateral pulmonary congestion was noted on chest radiography .
therefore , cmr and emb were carried out to confirm the diagnosis of hypersensitivity myocarditis .
contrast - enhanced cmr ( ce - cmr ) showed high signal intensities in circular and nodular patterns mainly in the epicardium and septum of the left ventricle ( fig .
these patterns suggested infiltrative myocarditis , such as amyloidosis , sarcoidosis , or eosinophilic myocarditis .
emb obtained from the septum of the right ventricle revealed lymphocytic and eosinophilic infiltration in the interstitium and perivascular area , findings that were consistent with a diagnosis of hypersensitivity myocarditis ( fig . 5 ) .
levels of ck - mb and troponin - i were normalized on days 6 and 9 , respectively .
the peripheral eosinophil count decreased from 1,380/mm to 620/mm on day 2 and was normalized ( 50/mm ) on day 4 .
the skin rash disappeared almost completely after use of 5 mg prednisolone , and the patient was discharged from the hospital on day 12 .
echocardiography at the 6-month follow - up showed normalized regional wall motion abnormalities and improved lv systolic function from 50% to 70% of the ejection fraction . at the 6-month follow - up , ce - cmr showed that previously high signal intensities in circular patterns in the epicardium of the left ventricle had disappeared and the oval - shaped area of high signal intensity in the lv septum had decreased in size ( fig .
eosinophilic myocarditis can be classified according to cause and includes those types associated with systemic disease ( e.g. , hypereosinophilic syndrome , churg - strauss syndrome , malignancies ) , parasitic infections ( e.g. , toxocara canis ) , and drugs or vaccines ( hypersensitivity myocarditis ) .
eosinophilic myocarditis associated with hypereosinophilic syndrome is usually underpinned by a history of peripheral eosinophilia ( > 1.5  10/l ) lasting > 6 months and is related to systemic involvement ( e.g. , central nervous system , gastrointestinal tract , heart , skin , or lung ) . in the present case ,
hypereosinophilic syndrome and parasitic infection were excluded because the patient did not have a history of prolonged eosinophilia , other organ involvement , or ingestion of raw meat .
instead , she had a history of taking multiple medications , urticaria , and peripheral eosinophilia
drug - related myocarditis can be classified into five types : 1 ) hypersensitivity myocarditis ; 2 ) toxic myocarditis ; 3 ) endocardial fibrosis ( e.g. , ergotamine tartrate , methysergide , phentermine , fenfluramine ) ; 4 ) drug - induced cardiomyopathy ( e.g. , anthracycline , chloroquine ) ; and 5 ) giant cell myocarditis .
numerous medications , including clozapine , sulfonamide , penicillin antibiotics , methyldopa , and some antiseizure drugs , have been reported to be associated with hypersensitivity myocarditis .
delayed hypersensitivity is the main pathogenesis and occurs from several days to months after administration of the causative agent .
hypersensitivity myocarditis is not easy to recognize because the clinical features suggestive of drug hypersensitivity reactions ( e.g. , urticaria , angioedema , malaise , fever , eosinophilia ) do not occur uniformly .
however , if tissue necrosis or deterioration of clinical status is observed , corticosteroid and cytotoxic agents can be used .
emb is the gold standard tool in the diagnosis of myocarditis . according to the dallas criteria ,
eosinophils may be a minor component of postviral and giant cell myocarditis but are predominant in hypersensitivity and parasitic myocarditis as well as hypereosinophilic syndrome .
lymphocytic and eosinophilic infiltrates with slight myocyte necrosis were observed in our case , which coincided with hypersensitivity myocarditis .
myocarditis is often a focal process , so sampling error may occur and increase the false - negative rate .
a previous study of endomyocardial samples obtained from the hearts of patients who died of myocarditis performed at the mayo clinic reported a false - negative rate of 37% for the right ventricle .
other limitations of emb include the aggressiveness of the procedure as well as the delay until confirmation of the result .
the lake louise criteria were found to have a sensitivity of 67% , specificity of 91% , accuracy of 78% , positive predictive value of 91% , and negative predictive value of 69% , when the criteria were compared with clinical or histopathological data .
mahrholdt and sechtem   reported recently that cmr - guided biopsy improved the sensitivity of emb .
thus , the combined application of cmr and emb may yield diagnostic synergy and overcome some of the limitations of cmr or emb when applied individually . in our case , we performed cmr - guided emb on the right ventricular septum , in which we detected regional high signal intensity on late gadolinium enhancement . in conclusion ,
careful history taking ( especially with regard to drugs ) , thorough physical examination , and clinical suspicion can help in recognizing hypersensitivity myocarditis both accurately and promptly .
cmr - guided emb is a valuable tool for the early and appropriate diagnosis for hypersensitivity myocarditis .
our patient recovered completely after cessation of administration of the causative drug and short - term administration of prednisolone for rapidly worsening hypersensitivity myocarditis .
 myocarditis often occurs due to viral infections and postviral immune - mediated responses . 
 hypersensitivity myocarditis is a rare form of myocarditis . 
 numerous drugs can induce myocarditis , which is typically reversible after withdrawal of the causative agent . here , we report a case of hypersensitivity myocarditis that was probably triggered by amoxicillin and that resolved completely with heart failure management as well as discontinuation of the drug . a 68-year - old woman presented with acute chest pain mimicking acute coronary syndromes , but the coronary angiography was normal . a recent history of taking medications , skin rash , and peripheral eosinophilia suggested a diagnosis of hypersensitivity myocarditis , which was confirmed by cardiac magnetic resonance imaging and endomyocardial biopsy . 
INTRODUCTION
CASE REPORT
DISCUSSION