Letter by Pieroni et al Regarding Article, “Contrast-Enhanced Magnetic Resonance Imaging of a Patient With Chloroquine-Induced Cardiomyopathy Confirmed by Endomyocardial Biopsy”
To the Editor:
We read with interest the article by Reffelmann et al1 describing a case of chloroquine-induced cardiomyopathy. Regarding the images provided by the authors, we would like to emphasize that magnetic resonance and mostly ultrastructural findings cannot univocally be referred to as chloroquine toxicity, because they might also represent typical pathological features of cardiac Fabry disease.2 In fact, both disorders are characterized by ineffective lysosomal metabolism caused by inherited genetic defects in Fabry disease or induced by chloroquine through an increase in pH, leading to accumulation of lysosomal glycosphingolipids and thickening of cardiac walls.
Comparison of ultrastructural findings in Fabry disease and chloroquine-induced cardiomyopathy has shown that concentric lamellar pseudomyeloid bodies are a common finding in both cardiomyopathies, suggesting that the only distinctive feature of chloroquine damage is represented by curvilinear bodies3 that are not evident in the images provided.
Despite the clinical history of long-lasting chloroquine assumption, in the absence of typical pathognomonic histological features, Fabry disease should have been excluded by enzymatic and genetic tests and also through familial history, mostly in the presence of renal failure, a typical feature of Fabry disease. Differential diagnosis between the 2 entities is clinically relevant because chloroquine withdrawal and enzyme-replacement therapy may be effective in reverting chloroquine-induced and Fabry disease cardiomyopathy, respectively.
We agree with the authors that cardiac magnetic resonance may be useful in the noninvasive evaluation of patients with long-lasting chloroquine intake, and we suggest that Fabry disease cardiomyopathy should always be considered in the differential diagnosis of idiopathic cardiac-wall thickening.