The Blue team reviewed a case in noon report this week of a patient with recently diagnosed idiopathic cardiomyopathy who presented with progressive dyspnea on exertion.
Cardiomyopathies can broadly be characterized to causes of ischemic vs. non-ischemic. Dilated cardiomyopathy (DCM) refers to a group of heterogenous cardiac disorders characterized by ventricular dilation and depressed cardiac function in the absence of hypertension, valvular, congenital, or ischemic heart disease. Etiologies can be further split into primary causes, meaning those related to issues with myocardium, versus secondary, i.e. those due to systemic cause. Drugs and toxins are a common cause with alcohol being the cause in about 25% cases of DCM. Cocaine, methamphetamines, and certain chemotherapies remain other less common causes. Myocarditis is another common cause, with viral being most common instigator. Other implicated etiologies of myocarditis include autoimmune disorders as well as bacterial, fungal, parasitic infections. The presence of a pericardial effusion supports myocarditis. Certain features on cardiac MRI including late gadolinium enhancement in conjunction with edema are suggestive of myocarditis. Other etiologies of DCM include genetic disorders, errors in metabolism, amyloidosis, stress-induced cardiomyopathy/tokotsubo, and endocrine disorders (both hyper- and hypothyroidism, diabetes, Cushing’s, Addison’s). Patients with DCM typically present with heart failure symptoms including DOE, peripheral edema in 80% of cases. Initial workup includes EKG, chest x-ray, echocardiogram, and labs including BNP. For further discussion on pathophysiology and treatment of DCM check out these review articles here and here.
- Bozkurt, B et al. “Current Diagnostic and Treatment Strategies for Specific Dilated Cardiomyopathies.” Circulation. 2016; 134: e1-69.
- Weintraub, R et al. “Dilated Cardiomyopathy.” Lancet. 2017; 390: 400-14.
- Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN2002-4436.
Authored by: GREGORY WIGGER, MD