Cardiac amyloidosis (CA) is relatively rare and frequently misdiagnosed. Other disorders presenting with increased left ventricular (LV) mass can mimic its diagnosis. This case illustrates unique findings of primary light chain (AL) amyloidosis in a patient with remarkable signs of CA. Here, we report a 49-year-old male with prior diagnosis of hypertrophic cardiomyopathy (HCM) based on an echocardiogram performed 1 year earlier, which presented with 8 weeks of periorbital rash. The patient had numbness in the past 3 years. More recently, the patient presented with shortness of breath. Physical examination was remarkable for periorbital purpura, macroglossia and orthostatic hypotension. Cardiac auscultation showed S3 and S4. Electrocardiography showed diffuse low-voltage QRS complexes. Echocardiography revealed severe diastolic impairment; granular ‘sparkling’ pattern of the myocardium with thickened walls, interatrial septum and valves; and pericardial effusion. Diastolic dysfunction and thick walls with low ECG voltage are compelling diagnostic findings. Laboratory workup showed increased free light chain-differential (FLC-diff), N-terminal fragment of brain natriuretic peptide (NT-BNP) and cardiac Troponin T (cTnT). Bone marrow biopsy confirmed AL amyloidosis. A diagnosis of AL amyloidosis with cardiac involvement mimicking HCM was made. The patient died during hospitalization due to sudden cardiac death. This case illustrates the importance of the combination of clinical, serological, and electro- and echocardiographic findings to establish the diagnosis of CA.
Several disorders presenting with increased LV mass can mimic CA.
Echocardiography is one of the most important methods to diagnose CA and HCM.
Signs of CA include LV wall thickness; thickening of interatrial septum, valves and right ventricular free wall; and pericardial effusion. Diastolic dysfunction and thick walls on echocardiography with low ECG voltage are the hallmark of disease.
CA is a major prognostic factor in AL amyloidosis.
Signs of HCM on echocardiography include several patterns of LV hypertrophy, such as sigmoidal, reverse curve, neutral and apical morphologies; LV outflow tract or mid-cavity obstruction; systolic anterior motion of mitral leaflets; mitral regurgitation and diastolic dysfunction.
The combination of clinical and serological features, along morphological and functional structures, has an important role for establishing diagnosis and predicting prognosis.