Loffler's endocarditis

NEJM Clinical Pearls

Morning Report Questions
Q: What is Loffler's endocarditis?
A: Loffler's endocarditis is a restrictive cardiomyopathy due to endomyocardial disease with mural thrombi (so-called thrombotic endocarditis) and is secondary to eosinophilia from many causes. Peripheral eosinophilia is almost always present in Loffler's endocarditis, usually present in acute necrotizing eosinophilic myocarditis, sometimes present in hypersensitivity myocarditis, and rarely present in endomyocardial fibrosis (a restrictive cardiomyopathy affecting persons in tropical climates).

Q: What is a known side effect of the medication modafinil used for treatment of fatigue in patients with multiple sclerosis?
A: Modafinil can cause multiorgan hypersensitivity reactions. The Food and Drug Administration now requires a package insert for modafinil that includes this warning. Drugs that have been associated specifically with hypersensitivity myocarditis include antibiotics (sulfonamides, beta-lactams, tetracyclines, aminoglycosides, and others), cardiac medications (methyldopa, dobutamine, thiazides, and furosemide), antiepileptics (phenytoin, carbamazepine), psychotropics, antimycobacterials (streptomycin), and nonsteroidal antiinflammatory drugs.

Acute Eosinophilic Myocarditis
Acute eosinophilic myocarditis (also known as hypersensitivity myocarditis) is caused by a drug hypersensitivity reaction and is characterized by fever, rash, peripheral eosinophilia, and elevated biomarkers of necrosis. ECG occasionally shows ST-segment elevation. Echocardiography reveals mild systolic dysfunction, increased wall thickness due to edema, and occasionally a pericardial effusion. Heart failure is typically mild, and patients die of arrhythmias, rather than pump dysfunction.

Autoimmune Myocarditis and Viral Myocarditis
Autoimmune myocarditis can occur in patients with autoimmune disorders such as systemic lupus erythematosus and polymyositis. Both can cause pericarditis and myocarditis, but the myocarditis tends to be mild. Viral myocarditis is often preceded by a viral syndrome, although this finding is neither sensitive nor specific. Presentations range from slow development of heart failure to rapid development of cardiogenic shock. The ECG often shows nonspecific ST-segment and T-wave abnormalities; echocardiographic findings range from a nondilated left ventricle seen in the acute phase to a spherical, dilated left ventricle in the chronic phase.