Cardiac Amyloidosis

A Treatable Disease, Often Overlooked

Case presentation: A 55-year-old woman, who had previously been very physically active, noted a gradual decrease in exercise tolerance over a period of 3 to 4 months to the extent that she had to rest briefly after climbing a single flight of stairs. She had consulted a dermatologist 6 months earlier because of recurrent, small bruises of her eyelids, but no cause had been found. An ECG suggested an old myocardial infarction with an unusual axis (Figure 1), and a cardiology consultation described symmetrical left ventricular hypertrophy on the echocardiogram with normal left ventricular ejection fraction, normally functioning valves, and mild right ventricular hypertrophy. There was no family history of cardiovascular or neurological disease. Physical examination revealed mild elevation of the jugular venous pressure, normal heart sounds, no murmurs, and mild peripheral edema with clear lung fields and a mildly congested liver. Blood pressure was 110/65 mm Hg. There was 1+ proteinuria. Serum protein electrophoresis revealed no abnormal bands, but serum immunofixation revealed a monoclonal spike determined to be IgG_λ. A bone marrow biopsy demonstrated 5% to 10% monotypical plasma cells staining for λ light chains. Serum-free light chains showed an elevation in free λ with an abnormal κ/λ ratio. Brain natriuretic peptide was 1019 pg/mL (normal <100), and troponin I was 0.07 ng/mL (normal <0.01). Endomyocardial biopsy (Figure 2) showed extracellular amorphous material that stained with Congo red and sulfated Alcian blue and that, on immunohistochemistry, reacted with antibodies to λ light chains but not to κ, …