VN April 2021

Vetnuus | April 2021 12 Thoracic radiographs (Figures 5 and 6) revealed marked cardiomegaly with a globoid cardiac silhouette and severe left atrial enlargement. Pulmonary venous congestion and an interstitial pulmonary pattern in the perihilar and caudal lung fields were consistent with cardiogenic pulmonary oedema. Because of the patient’s dietary history of being fed a grain-free diet for the last 2.5 years and concern for diet-associated DCM, whole blood and plasma taurine levels were evaluated and found to be normal (plasma taurine, 112 nmol/mL; reference range, 60-120 nmol/mL: whole blood taurine, 262 nmol/mL; reference range, 200- 350 nmol/mL). 4 Cardiomyopathy secondary to taurine deficiency has been reported in golden retrievers 5-7 and cocker spaniels, which are taurine- and L-carnitine–responsive breeds. 7,8 Grain-free diets have been linked to DCM in patients with normal taurine levels, suggesting an alternative mechanism in the development of DCM. Potential mechanisms are under investigation. DCM may be suspected based on dietary history, breed (i.e., atypical breed for DCM, lack of familial history, breed predisposition), and the elimination of other underlying causes (i.e., myocarditis, toxicity, tachycardia-mediated cardiomyopathy). DIAGNOSIS: DIET-ASSOCIATED DILATED CARDIOMYOPATHY Treatment & Long-TermManagement Cardiac medications for management of CHF and systolic dysfunction, including furosemide (2.14 mg/kg PO q12h), pimobendan (0.27 mg/kg PO q12h), and enalapril (0.53 mg/kg PO q12h), were initiated. Taurine (26.7 mg/kg PO q12h) was added as a supplement due to concern for diet-associated DCM. Because the exact mechanism of diet-associated DCM is not well understood and taurine has been shown to be beneficial for cardiovascular disease (i.e., antioxidant effects, protection against ischemia-reperfusion injury, modulation of intracellular calcium concentrations), taurine supplementation was continued in this patient. Nora was transitioned to a commercial, non-boutique, non- exotic protein, non-grain-free diet (see Treatment at a Glance). Nora was presented for a recheck examination with thoracic radiography, renal values with electrolytes, and blood pressure 10 days after starting cardiac medications. Results of the subsequent testing revealed adequate control of CHF and radiographic resolution of pulmonary oedema. FIGURE 4: 2D echocardiographic image with color Doppler from the left parasternal apical view. There is severe dilation of the left atrium, left ventricle, and mitral valve annulus resulting in a central jet of mitral regurgitation. Mitral valve leaflets are normal in thickness, with no evidence of degenerative mitral valve disease. FIGURE 5: Ventrodorsal thoracic radiograph obtained one day after starting cardiac medications for CHF secondary to suspected diet-associated DCM. There is severe cardiomegaly with resolving pulmonary oedema. FIGURE 6: Left lateral thoracic radiograph obtained one day after starting cardiac medications for CHF secondary to suspected diet-associated DCM. There is severe cardiomegaly with resolving pulmonary oedema. Article