X-Linked Dilated Cardiomyopathy Presenting as Acute Rhabdomyolysis and Presumed Epstein-Barr Virus-Induced Viral Myocarditis: A Case Report.

BACKGROUND Rhabdomyolysis and primary dilated cardiomyopathies without skeletal muscle weakness are rare features of X-linked dystrophinopathies. We report a rare case of an X-linked dilated cardiomyopathy (XLDCM) presenting with acute rhabdomyolysis and myocarditis. We illustrate the confounding diagnostic influence of a reactivated, persistent EBV myocarditis as the presumed cause for this patient's XLDCM. CASE REPORT A 23-year-old Australian man presented with acute rhabdomyolysis and elevated creatine kinase (CK) levels. He was managed conservatively with intravenous hydration and developed acute pulmonary edema. Cardiac MRI and transthoracic echocardiogram revealed a dilated cardiomyopathy and viral myocarditis. Extensive sero-logical investigations identified reactivation of EBV, which was presumed to account for his viral myocarditis. The patient recovered and was discharged with down-trending CK levels. Follow-up transthoracic echocardiograms and cardiac MRI showed a persisting dilated cardiomyopathy. His CK continued to remain elevated and his EBV IgM serology remained positive. An inflammatory polymyositis with either a primary autoimmune pathophysiology or secondary to a chronic EBV infection was considered. Oral corticosteroids were trialed and reduced his CK significantly until therapy was ceased. Massively parallel sequencing eventually identified a two-exon deletion targeting Xp21 consistent with the diagnosis of a rare XLDCM. CONCLUSIONS Rhabdomyolysis and co-existing primary dilated cardiomyopathies are rare diagnostic manifestations in a minority of X-linked dystrophinopathies. Chronic viral infections and their reactivation may complicate the diagnostic process and incorrectly attribute an inherited cardiomyopathy to an acquired infective etiology. EBV reactivation rarely induces myocarditis. Therefore, primary and unresolving dilated cardiomyopathy with persistently elevated CK must prompt consideration of an underlying dystrophinopathy.